                        Changes in version 6.4.1                        

    o   Some tests were adjusted to accommodate changes in R-devel.
	Specifically, a long-standing bug in `rbinom` was fixed, which
	changes the results of some pomp calculations.

                        Changes in version 6.3.1                        

    o   coef can now extract parameters by name from a ‘listie’.

                        Changes in version 6.2.1                        

    o   The built-in examples that use simulated data add a seed
	argument to allow changing the simulated data.

                        Changes in version 6.1.1                        

    o   The basic Kalman filter (kalmanFilter) has been refactored,
	with a roughly 3-fold speed up.

    o   Some internal changes have been made in anticipation of changes
	to the C API for R.

                        Changes in version 6.0.5                        

    o   It is now possible to specify more than one lag in the ivp
	function, which is evaluated only when the mif2 perturbations
	are specified.  See ?mif2.

                        Changes in version 6.0.4                        

    o   The new function append_data appends a data frame to an
	existing CSV file (creating the file if it does not exist).
	This facilitates keeping a database of parameter-space
	explorations.

                        Changes in version 6.0.3                        

    o   The new function eeulermultinom gives the expectation of an
	Euler-multinomial random variable.

                        Changes in version 6.0.2                        

    o   The save.states option to pfilter has changed.  See ?pfilter
	and ?saved_states for details.

                        Changes in version 6.0.1                        

    o   In calls to pomp elementary and inference algorithms, it is now
	necessary to pass all arguments by name.  This has always been
	good practice, but from this release, calls that rely on the
	position of arguments will typically generate errors.

                        Changes in version 6.0.0                        

    o   From version 5.8.4, the manner in which extra model elements
	(userdata) are supplied has changed.  As of that version, use
	of the old method generated a warning.  As of this version, an
	error will be generated.  To supply additional elements (i.e.,
	beyond parameters, latent-state variables, observations, and
	covariates) to the basic model components, provide them as a
	list via the userdata argument.

                       Changes in version 5.11.1                        

    o   A new addition to the C API allows one to easily compute the
	expectation of the Euler-multinomial.  The function is
	eeulermultinom.

    o   The help-page discussion of accumulator variables has been
	expanded and clarified.

                       Changes in version 5.10.1                        

    o   An improper typecast in the C snippet system, which was
	resolvable by many compilers but threw an error under recent
	versions of clang on MacOS, has been repaired.

                        Changes in version 5.9.1                        

    o   The rprocess plugin onestep now always takes exactly one step
	to get from one observation time to the next, even when the
	interval between them is zero.  That is, if P is a ‘pomp’
	object with an rprocess built using rprocess=onestep(f),
	t0=timezero(P), and t=time(P), then f will be called exactly
	once for the interval (t0,t[1]) and once for each of the
	intervals (t[i-1],t[i]), i=2,...,length(t).

                        Changes in version 5.8.4                        

    o   To add additional elements for use by the basic model
	components (i.e., “userdata”), the userdata argument should now
	be used.  The old behavior will still work, but will generate a
	warning.  In a future release, this will become an error.

                        Changes in version 5.8.3                        

    o   Internally, pomp codes no longer include Rinternal.h.

                        Changes in version 5.8.2                        

    o   A bug in covariate-table extrapolation for the case
	order="constant" has been fixed.

    o   A new experimental function repair_lookup_table is provided to
	help eliminate unnecessary warnings about extrapolation.

                        Changes in version 5.8.1                        

    o   Functions with names that include dots (.), which have been
	defunct since version 4.7, have been expunged.

                        Changes in version 5.7.1                        

    o   The err() and warn() C-level macros have been redefined to
	forestall problems that would arise when these macros are
	included in C++ code under forthcoming versions of R.

    o   More changes in C codes to forestall issues detected by rchk.

    o   Minor corrections to documentation.

                        Changes in version 5.6.1                        

    o   Minor corrections to documentation.

    o   Changes in some C codes to avoid issues detected by rchk.

    o   Fixed bug in wquant introduced by changes in pbeta with R
	version 4.3.3.

                        Changes in version 5.5.2                        

    o   Minor corrections to documentation.

                        Changes in version 5.5.1                        

    o   C-level functions set_pomp_userdata and unset_pomp_userdata are
	no longer exported.

    o   bspline_eval is no longer exported.

                        Changes in version 5.4.4                        

    o   C-level functions set_pomp_userdata and unset_pomp_userdata
	have been temporarily restored.  The latter generates a
	warning.

                        Changes in version 5.4.3                        

    o   There is now access to ordinary B-spline basis functions (and
	their derivatives) at the C snippet level.  It will still
	almost always be preferable to construct a spline basis once
	and pass it to pomp functions as part of a covariate_table, but
	this functionality may occasionally be useful.

    o   bspline_eval is now deprecated as part of the pomp C API.

    o   The formatting of some printed messages has been modified to
	forestall warnings in the latest R-devel.

                        Changes in version 5.4.2                        

    o   Stateful objective functions (class ‘objfun’) now behave as if
	they are ‘pomp’ objects.

                        Changes in version 5.4.1                        

    o   C-level functions set_pomp_userdata and unset_pomp_userdata are
	no longer exported.

                        Changes in version 5.3.1                        

    o   stew now returns timing information by default.

    o   The spurious warnings associated with NULL userdata have been
	eliminated.

                        Changes in version 5.2.5                        

    o   The new option on_load allows one to specify a C snippet that
	will be executed at the time the C snippet library is loaded.

    o   Internally, the userdata are made available via calls to
	pompLoad rather than within each call to a pomp workhorse.

                        Changes in version 5.2.4                        

    o   The data frames returned by cond_logLik and eff_sample_size
	when format="data.frame" have been improved.  In particular,
	they contain (as variable time) the times (rather than the
	index of the time vector as before).

    o   Changes to the report generated by spy.

    o   Some documentation improvements.

                        Changes in version 5.2.3                        

    o   The manual pages have been reorganized, with improved
	cross-linking.

    o   A bug in filter_traj etc. arising when not all state variables
	have names was fixed.

                        Changes in version 5.2.2                        

    o   This version adds the new basic component dinit for evaluating
	the probability density function of the initial-state
	distribution.  There is a corresponding workhorse function,
	dinit().

    o   The constructor pomp now takes the optional argument
	nstatevars, which can be used to increase the dimension of the
	latent state-vectors created by rinit.  By default, nstatevars
	= length(statenames), and nstatevars can only be used to
	_increase_, not to decrease, the dimension of the latent state
	process.  Moreover, nstatevars has no effect if the rinit basic
	component is furnished as an R function.

    o   Name checking on internally-created vectors and arrays is less
	strict than previously.  In particular, it is possible to have
	variables without names (i.e., "").

                        Changes in version 5.2.1                        

    o   reulermultinom now returns NA rather than NaN, in keeping with
	the behavior of rbinom.  Thanks to John Drake for calling
	attention to this issue.

                        Changes in version 5.1.1                        

    o   A bug in stew resulting in namespace conflicts has been
	repaired.

    o   We no longer import directly from tidyverse functions.  This
	reduces the list of packages upon which pomp depends from 20 to
	5.  This does introduce a dependency on the data.table package.

                        Changes in version 5.0.1                        

    o   When the archive directory does not exist, bake and stew now
	create it.

                        Changes in version 5.0.0                        

    o   We no longer import from plyr.

    o   The dimnames attributes of various arrays that appear in pomp,
	including arrays of observables, state variables, parameters,
	covariates, and so on, have been made uniform.  In particular,
	when a dimension of an array corresponds to variables with
	different names, this dimension is itself named “name”.
	Previously, its name was sometimes “variable” and sometimes
	“parameter”.  This change is meant to streamline interaction
	with the tidyverse.

    o   Some minor bugfixes.

                        Changes in version 4.7.0                        

    o   Functions with names.that.contain.dots that have been
	deprecated since version 4.5.1 are now defunct.  Attempts to
	use such functions will generate an error with a message
	indicating the replacement function.

    o   plot now removes NA.

                        Changes in version 4.6.4                        

    o   Better handling of ‘listie’s (lists of ‘pomp’ objects).

    o   New concat function to turn lists of ‘pomp’ objects into
	‘listies’.

                        Changes in version 4.6.3                        

    o   Bug fix in filter_traj applied to ‘pfilterList’ and ‘pmcmcList’
	objects.

                        Changes in version 4.6.2                        

    o   The states and obs methods take a new optional argument,
	format.  Setting format="data.frame" causes the method to
	return the states or data in a convenient data-frame format.

                        Changes in version 4.6.1                        

    o   When melt is applied to a list, the identifier variable is now
	“.Lx”, where x denotes the level.  This applies when
	as.data.frame is used to coerce a list of ‘pomp’ objects, and
	when saved_states is used to extract the particles from a list
	of ‘pfilterd_pomp’ objects.

                        Changes in version 4.5.3                        

    o   logmeanexp can now compute the effective sample size, which can
	be useful in determining the reliability of its estimate.  To
	do so, set ess=TRUE in a call to logmeanexp.

    o   logmeanexp now returns a fully-named vector when either se=TRUE
	or ess=TRUE.

                        Changes in version 4.5.2                        

    o   A new format argument has been added to the extractor functions
	cond_logLik, eff_sample_size, filter_mean, filter_traj,
	forecast, pred_mean, pred_var, and saved_states.  This allows
	the user to extract the relevant elements in data-frame format
	if desired.

    o   pomp no longer depends on the superseded package reshape2.  The
	melt function for converting arrays and nested lists into data
	frames is accordingly no longer re-exported from reshape2.  It
	has been replaced by a stricter version of melt.

    o   The magrittr pipe %>% is no longer re-exported by pomp: use the
	native R pipe |> instead.

    o   The package now requires R version 4.1 at least.

                        Changes in version 4.5.1                        

    o   All pomp functions with names.that.contain.dots have been
	deprecated in favor of functions in ‘snake_case’.  This is to
	avoid anticipated problems with CRAN checks, which (falsely)
	assume that certain functions with dotted.names are S3 methods.
	From this point, no exported pomp function has such a name.

    o   The dimnames attributes for some of the arrays computed in
	pfilter and pmcmc computations have changed.  In particular,
	whereas in previous versions, the time dimension was given
	names that were character strings composed of decimal
	representations of the time (difficult to work with and prone
	to roundoff error), the time dimension now is not given names.

    o   A bug that resulted in gompertz giving different simulations on
	Windows machines has been fixed.

                        Changes in version 4.4.3                        

    o   A bug in trajectory computation for maps (discrete-time
	dynamical systems) has been fixed.  Thanks to Felicia Magpantay
	for noticing it and tracking it down.

    o   Minor documentation improvements.

                        Changes in version 4.4.2                        

    o   The weighted quantile function wquant now uses the
	Harrell-Davis estimator instead of the type-7 estimator used
	previously.  This eliminates bugs associated with non-integer
	weights.

                        Changes in version 4.4.1                        

    o   It is now possible to retrieve the weighted particles computed
	in the course of a pfilter computation.  To accomplish this,
	set save.states="weighted" in the call to pfilter and retrieve
	the particles and their weights using saved.states.
	Previously, one could obtain only the unweighted particles.

                        Changes in version 4.4.0                        

    o   Some documentation improvements.

                        Changes in version 4.3.4                        

    o   The new function wquant computes weighted quantiles.

                        Changes in version 4.3.3                        

    o   The precise order in which the pmcmc function computes prior
	and likelihood of furnished and proposed parameters has changed
	slightly.  This prevents proposals that are incompatible with
	the prior from being passed to pfilter and forestalls an
	associated class of errors.  A consequence of this change,
	pmcmc computations using the new version will differ very
	slightly from previous computations, even with the RNG seed
	fixed at its previous values.

                        Changes in version 4.3.2                        

    o   There is now a C interface to the bspline_eval function.  See
	the pomp C API documentation for details.

                        Changes in version 4.3.1                        

    o   The bspline.basis function now takes the optional argument rg
	which allows one to specify the range over which the basis will
	be constructed.  By default, this is range(x), which agrees
	with the behavior in earlier versions.

    o   Documentation improvements.

                        Changes in version 4.2.2                        

    o   The archiving functions bake and stew now use a slightly less
	exacting comparison of the expression, expr, they are
	furnished.  *NB:* Running bake or stew with archives created by
	earlier versions may result in recomputation.

    o   The time method has been extended to pompList and related
	objects.

    o   All workhorse functions except partrans have new default
	arguments.

    o   Some documentation improvements.

                        Changes in version 4.2.1                        

    o   The archiving functions bake and stew now take the argument
	dir, which is the directory holding the archive files.  By
	default, this is the current working directory or the value of
	the global option pomp.archive.dir.

    o   A new global option, pomp_archive_dir, can be used to specify
	the locations of archive files used by bake and stew.

    o   Documentation repair of issue flagged by Kurt Hornik (9 June
	2022).

                        Changes in version 4.2.0                        

    o   Minor changes, invisible to the user.

    o   Minor changes to the C codes to keep up with R-devel.

                        Changes in version 4.1.0                        

    o   Minor changes to the C codes to keep up with R-devel.

    o   Minor changes in the implementation of bake and stew.

                       Changes in version 4.0.11                        

    o   Change in the names of the variables returned by as.data.frame
	applied to a ‘pfilterd.pomp’ object.

    o   Fixed bug found by Jesse Wheeler and Ed Ionides, to do with
	`simulate()` with `include.data=TRUE`.

                       Changes in version 4.0.10                        

    o   It is now possible to plot lists of ‘pomp’ and ‘pomp’-derived
	objects using a single call to plot.

                        Changes in version 4.0.9                        

    o   The rbetabinom and dbetabinom functions, long present as part
	of the C API, are now available as R functions.

                        Changes in version 4.0.8                        

    o   The SIR examples sir() and sir2() now use a negative binomial
	measurement model.

                        Changes in version 4.0.7                        

    o   parmat can now take a data frame of parameters and convert it
	into a matrix suitable for furnishing to the params argument of
	any pomp function.

                        Changes in version 4.0.6                        

    o   It is now possible to change the parameters in an ‘objfun’
	(objective function) object using coef(object)<-value.

                        Changes in version 4.0.5                        

    o   parmat now takes an optional argument, names, which allows the
	user to name the parameter sets.

    o   Independent realizations of the stochastic processes modeled in
	pomp are now distinguished by different values of .id.  This
	behavior is now uniform throughout.

    o   bake and stew now send messages instead of warnings when they
	recompute an archive due to a change in code or dependencies.

                        Changes in version 4.0.4                        

    o   The ensemble adjusted Kalman filter (eakf) has been refactored.
	It now makes use of the emeasure and vmeasure basic components
	to compute an approximation of the linear relationship between
	the latent state and the observed variables.

    o   The forecast method now works for pfiterd_pomp objects (i.e.,
	results of pfilter, pmcmc, or mif2 computations).

                        Changes in version 4.0.3                        

    o   Two new basic model components have been introduced.  These
	are:
	
	emeasure,
	    which computes the expectation of the observable variables
	    conditional on the latent state;
	
	vmeasure,
	    which computes the covariance matrix of the observables
	    given the latent state.
	
	These are used by the newly refactored ensemble Kalman filter,
	enkf.

    o   The basic (linear, Gaussian) Kalman filter is now available as
	kalmanFilter.

                        Changes in version 4.0.2                        

    o   Computation of Monte Carlo-adjusted profile likelihood is now
	facilitated by the new mcap function.

                        Changes in version 4.0.1                        

    o   The default return-value format for trajectory now matches that
	of simulate.

                        Changes in version 4.0.0                        

    o   The behavior of trajectory now fully conforms to the behavior
	of other pomp elementary functions.  In particular, one can now
	add, remove, or modify basic model components in a call to
	trajectory just as one can with simulate, pfilter, probe, etc.
	Before version 4, additional arguments to trajectory (i.e.,
	those passed via ...) were passed on to the ODE integrator in
	the case of continuous-time deterministic skeletons (i.e.,
	vectorfields) and ignored in the case of discrete-time
	skeletons (i.e., maps).  As of version 4, in order to adjust
	ODE integrator settings it is necessary to use the ode_control
	argument of trajectory.  This behavior matches that of
	traj_objfun.

    o   It is now possible to create a ‘pomp’ object from scratch using
	trajectory, together with a specification of the rinit and
	skeleton components.  Prior to version 4, in order to do so, it
	was necessary to first create a dummy data set, then call pomp,
	and then pass the resulting ‘pomp’ object to trajectory.  This
	can now be achieved in one call.

    o   The user now has the option, in a call to trajectory, to have
	the results returned as one or ‘pomp’ objects.  In this regard,
	its behavior matches that of simulate.

                        Changes in version 3.5.6                        

    o   The states and obs methods now work for lists of ‘pomp’ objects
	(‘listies’).

                        Changes in version 3.5.5                        

    o   The workhorse function flow now has default arguments.

    o   The stateful objective function created by traj_objfun has been
	refactored so that it is independent of trajectory.  This
	change is invisible to the user, but lays the groundwork for
	future changes in trajectory.

                        Changes in version 3.5.4                        

    o   Stateful objective functions created by traj_objfun,
	nlf_objfun, probe_objfun, and spect_objfun now have default
	arguments.  In particular, the default is argument is a
	zero-length numeric vector.  Calling such a function with no
	arguments is valid if and only if the objective function was
	created with no variables to estimate (empty est).

                        Changes in version 3.5.3                        

    o   Fixed bug in rprior arising with integer-valued return vectors.

                        Changes in version 3.5.2                        

    o   Major improvements to the package manual, including richer
	cross-linking and better organization.

                        Changes in version 3.5.1                        

    o   When simulate is called with format="data.frame" and
	include.data=TRUE, the interpolated covariates are now included
	in the data frame that is returned.

                        Changes in version 3.4.6                        

    o   bake takes a new option, timing, that controls whether
	information on the timing is returned or merely stored.  By
	default, this is set to TRUE, though this default behavior may
	change in future.

                        Changes in version 3.4.5                        

    o   When they encounter an archive produced by an older version,
	bake and stew now update the archive in the new format.
	Recomputation should never be triggered in this case: If
	recomputation is desired, delete the archive file.

                        Changes in version 3.4.4                        

    o   bake and stew now archive a digest of the code in expr and on
	subsequent calls check to see if the archived version matches
	the current version.  Thus, changes to the code automatically
	trigger recomputation.

    o   bake and stew take the new argument dependson.  Using this
	argument, the user can specify objects upon which the
	computation depends.  These should be passed as unquoted
	variables; if there are multiple dependencies, they can be
	passed using c or list.  Digests of these objects will be
	archived and checked against current values on subsequent
	calls.  Thus, changing any dependency will automatically
	trigger recomputation.

    o   bake now archives the information pertinent to the bake call;
	this information is no longer returned along with the result of
	the computation (unless info=TRUE).  Similarly, stew stores a
	list, “.ingredients”, in the file it creates.  In the stew
	case, unlike all the other objects that are created by expr,
	this list is _not_ by default loaded into the calling
	environment (e.g., the user's workspace).  It will be loaded if
	the info flag is set to TRUE.

    o   freeze no longer stores the details of the RNG seed and kind as
	an attribute of the returned object.

                        Changes in version 3.4.2                        

    o   Fix bug in bsmc2 arising when some particles have zero
	likelihood.  This is Issue #152.  Thanks to Hola-Kwame Adrakey
	for reporting it.

                        Changes in version 3.4.1                        

    o   It is now possible to call partrans directly on an objective
	function, such as those created by traj_objfun, nlf_objfun,
	probe_objfun, or spect_objfun.

                        Changes in version 3.3.1                        

    o   The package manual and help pages has been streamlined.

    o   The mif2 diagnostic plots have been made more flexible.

    o   Some deprecated functions have been removed.  These include
	cond.loglik, sliceDesign, runifDesign, sobolDesign, and
	profileDesign, which have been replaced by code.logLik,
	slice_design, runif_design, sobol_design, and profile_design,
	respectively.

                        Changes in version 3.3.0                        

    o   A bug in rgammawn has been fixed.

                        Changes in version 3.2.0                        

    o   The pomp C API has been expanded a bit, to facilitate other
	packages' linking to the pomp library.

                        Changes in version 3.1.1                        

    o   The help pages have been improved, with an description of the
	overall package structure and pages on basic model components,
	elementary algorithms, and estimation algorithms.

    o   A note to Windows users on avoiding certain C snippet
	compilation errors has been added to the help pages.

    o   The behavior of profile_design has changed.  Previously, the
	same random (or sub-random) sequence was used for all
	non-profile parameters.  Now, for each profile slice, a
	distinct set of points is generated.

    o   profileDesign, sliceDesign, runifDesign, and sobolDesign have
	been deprecated and will be removed in a future release.  They
	are replaced by profile_design, slice_design, runif_design, and
	sobol_design, respectively.

                        Changes in version 3.0.3                        

    o   A new saved.states method allows one to extract the saved
	states from a particle filter computation.

                        Changes in version 3.0.2                        

    o   All instances of cond.loglik have been changed to cond.logLik,
	to remove a common source of typographical error.

                        Changes in version 3.0.1                        

    o   A new sequential importance sampling algorithm has been
	implemented as wpfilter.  This is a generalization of the
	algorithm in pfilter in that it tracks the weights of the
	particles and allows the user to customize the resampling
	scheme.

                        Changes in version 3.0.0                        

    o   In mif2, the specification of particle numbers, Np, has
	changed.  When Np is supplied as a function, Np(0) is the
	requested number of particles at the beginning of the time
	series.  The previous behavior was that Np(1) specified the
	requested number of particles.  This behavior now matches that
	of the other particle filtering algorithms, pfilter, bsmc2, and
	pmcmc.

    o   bsmc2 can now accept a variable number of particles, as do the
	other particle-filter based algorithms pfilter, pmcmc, and
	mif2.

    o   The internal systematic_resample function now allows the user
	to specify the number of samples desired.  Previously, these
	were always equal to the number of weights supplied.

    o   As promised from version 2.4.1, the tol and max.fail arguments
	have been removed completely from all particle-filtering
	algorithms, including pfilter, pmcmc, bsmc2, and mif2.  See the
	pomp news blog (<https://kingaa.github.io/pomp/blog.html>) for
	more information.

    o   The long-deprecated functions onestep.dens, onestep.sim,
	discrete.time.sim, euler.sim, gillespie.sim, gillespie.hl.sim,
	conv.rec, and values have been removed.  These have been
	replaced as follows
	
	  onestep.dens       direct specification of dprocess component 
	  onestep.sim        onestep                                    
	  discrete.time.sim  discrete_time                              
	  euler.sim          euler                                      
	  gillespie.sim      gillespie                                  
	  gillespie.hl.sim   gillespie_hl                               
	  conv.rec           traces                                     
	  values             as.data.frame or as(x,"data.frame")        
	 

                        Changes in version 2.8.0                        

    o   Trap error from non-finite likelihoods in pmcmc.

    o   New test of pmcmc codes in tests/issue109.R.

    o   Trap error from missing accumulator variables in trajectory.

                        Changes in version 2.7.2                        

    o   The Euler step size in sir is now adjustable.

                        Changes in version 2.7.1                        

    o   As promised, the default value of tol in the particle-filtering
	algorithms pfilter, pmcmc, mif2, and bsmc2 has been changed to
	zero.  A warning continues to be issued if tol is set to
	anything other than 0.  In a future release, the option to
	choose a nonzero tolerance will be removed entirely.

    o   In traces and diagnostic plotting methods, the nfail variable
	(tracking numbers of filtering failures) has been dropped.

                        Changes in version 2.6.0                        

    o   Another documentation bug was fixed.

                        Changes in version 2.5.0                        

    o   A documentation bug, identified by K. Hornik, was fixed.

                        Changes in version 2.4.1                        

    o   In anticipation of forthcoming algorithmic changes, the tol and
	max.fail arguments of pfilter, bsmc2, pmcmc, and mif2 are now
	deprecated.  A warning is issued if tol is set to anything
	other than 0.  In a future release, these options will be
	removed entirely: the behavior will be similar to that obtained
	in the present release by setting tol=0.

    o   A new example illustrating the accumvars argument has been
	provided.

    o   Internal computations now use increased precision for means,
	variances, and certain calculations with likelihoods.

    o   A new help page, pomp_examples, lists the various example
	datasets and pomp objects provided with the package.

                        Changes in version 2.3.0                        

    o   The source codes underlying specification of basic model
	components via R functions has been reworked to remove reliance
	on deep PROTECT stacks.  Thanks to Thomas Kalibera for showing
	the way!

    o   A bug in the documentation for filter.traj, pointed out by
	Pierre Jacob, has been fixed.

                        Changes in version 2.2.2                        

    o   The C API for pomp is no longer explained only in comments in
	the “pomp.h” header file.  It is now described and explained in
	the new C API vignette.

                        Changes in version 2.2.1                        

    o   The new pomp_cdir global option allows one to set the directory
	holding C snippet files globally.

    o   A bug caused by re-use of the cfile argument has been fixed.
	Re-use now triggers an error, with an informative message.

                        Changes in version 2.2.0                        

    o   Some documentation improvements.

                        Changes in version 2.1.2                        

    o   A bug in runifDesign (and therefore profileDesign when
	type="runif") has been fixed.

                        Changes in version 2.1.1                        

    o   There are now plot methods for objects of classes
	‘probe_match_objfun’ and ‘spect_match_objfun’.

                        Changes in version 2.1.0                        

    o   Released to CRAN.

                       Changes in version 2.0.14                        

    o   The melt function can now be applied to arbitrary ‘pomp’
	objects.

                       Changes in version 2.0.13                        

    o   A new function, runifDesign allows construction of design
	matrices using samples from multivariate uniform distributions.

    o   The profileDesign function takes a new argument, type, with two
	options: "sobol", the default, constructs the design using
	sobolDesign, as before.  "runif" uses the new runifDesign
	function.

                       Changes in version 2.0.12                        

    o   A new example, comprising models and data for the 2014-2016
	west African Ebola virus disease outbreak, is included.  See
	?ebola for details.

                       Changes in version 2.0.11                        

    o   It is now possible to adjust the observation times and
	zero-time in the sir and sir2 examples.  One can also change
	the default RNG seed used in generating the simulated data.

    o   The codes underlying the rprocess workhorse have been
	streamlined to obviate an unnecessary copy operation.  As a
	result, the interface to the rprocess workhorse has been
	changed.

    o   The interface to the new flow workhorse has been changed to
	match.

                       Changes in version 2.0.10                        

    o   The new flow workhorse allows integration/iteration of the
	deterministic skeleton at arbitrary times from an arbitrary
	initial condition.

                        Changes in version 2.0.9                        

    o   When coef is applied to a ‘listie’, the result can be more
	usefully melted.

    o   The probe-names returned by probe.acf and probe.ccf have
	changed.

    o   A bug, whereby the ‘coef’ method from other packages was
	masked, has been fixed.

    o   Errors in the documentation have been corrected.

                        Changes in version 2.0.8                        

    o   There is a new as.data.frame method for ‘listie’s.

    o   Some problems with the exposure of internal objects for package
	developers have been corrected.

                        Changes in version 2.0.7                        

    o   The magrittr pipe operator, %>%, is now re-exported.

                        Changes in version 2.0.6                        

    o   More examples have been included.

    o   Minor changes to error messages.

                        Changes in version 2.0.5                        

    o   The names of the ‘objfun’ methods have been changed to
	probe_objfun, spect_objfun, traj_objfun, and nlf_objfun.

                        Changes in version 2.0.4                        

    o   The package directory structure has been modified to include a
	new examples directory, which holds the examples used in the
	documentation.

    o   The names of the ‘objfun’ methods have been shortened.

                        Changes in version 2.0.3                        

    o   It is now permissible that the sequence of observation times
	(and sequences of covariate times) be merely non-decreasing
	sequences.  Previously, pomp insisted on strictly increasing
	time sequences.

    o   The default cooling schedule (cooling.type) in mif2 is now
	“geometric”, in contrast to “hyperbolic”, as before.

                        Changes in version 2.0.2                        

    o   pomp now requires at least R version 3.5.

                        Changes in version 2.0.1                        

    o   The zeronames argument has been renamed accumvars.

                        Changes in version 2.0.0                        

    o   In the course of ordinary work, one should never need to
	interact with the low-level pomp constructor function now.

    o   The pompExample function has been dropped.  The various
	examples are now included as regular functions that construct
	‘pomp’ objects.

    o   The bbs example has been dropped.

    o   One can now modify basic model components at (almost) any stage
	in a pipeline of pomp computations.  All the top-level
	inference functions, plus probe, pfilter, and simulate now
	allow modification of basic model components.

    o   The rprocess plugins onestep.sim, discrete.time.sim, euler.sim,
	gillespie.sim, and gillespie.hl.sim have been renamed onestep,
	discrete_time, euler, gillespie, and gillespie_hl,
	respectively.  The old usage is available but deprecated.

    o   One can now call simulate on a model without reference to any
	data.

    o   The covariate table facility (covariate_table) now supports
	piecewise constant interpolation.

    o   The syntax with which one includes covariates via
	covariate_table has become more flexible.  Specifically, the
	arguments to covariate_table are now evaluated sequentially, so
	that later ones can depend on earlier ones.  Once evaluated,
	the covariates are bound column-wise into a single data frame.

    o   The manner in which one writes R functions to specify basic
	model components has been totally changed.  Before, one wrote
	functions that took specific arguments such as 'x', 'params',
	and 'covars'.  Now, one writes such functions with any or all
	state variables, observables, covariates, and/or time as
	arguments.

    o   simulate now returns more informative results when simulations
	from multiple parameter sets are simultaneously computed.
	Specifically, if params has column names, these are used to
	identify the resulting simulations.  Thus when format = "pomps"
	(the default), the names of the resulting list will be
	constructed from the column names of params.  Likewise, when
	format = "arrays", the resulting arrays will have informative
	column names; When format = "data.frame", the identifier
	variable will make use of the column names.

    o   The basic particle filter, pfilter, has a simpler mode of
	operation: params should be a single parameter set only.  That
	is, it is no longer possible to pass a matrix of parameters to
	pfilter.

    o   The Liu-West algorithm, bsmc2, has a simpler mode of operation:
	params should be a single parameter set only: the SMC particles
	are drawn from rprior.

    o   The as.data.frame, states, and obs options for simulate have
	been done away with.  One now chooses the format of the
	returned simulations via the format argument.  When one
	simulates at multiple parameter sets, list names, array
	dimnames, or identifying variables in the output data frame
	help to correlate simulations with parameter sets.

    o   The as.data.frame argument to trajectory has been removed in
	favor of a new format argument that allows one to choose
	between receiving the results in the form of an "array" or a
	"data.frame".

    o   All the basic model components now have defaults.
	
	  • The default rinit behavior remains as it was: it assumes
	    the initial state distribution is concentrated at a point
	    mass determined by parameters with “.0” or “_0” suffices.
	
	  • The default process model is “missing”: calls to dprocess
	    and rprocess will result in missing values (NA).
	
	  • The default measurement model is “missing” as well.
	
	  • The default prior is flat and improper: all calls to the
	    default dprior result in 1 (0 if log = TRUE, and all calls
	    to rprior result in NA.
	
	  • The default skeleton is missing.
	
	  • The default parameter transformations remain the identity.

    o   The transform argument present in many pomp algorithms has been
	removed.  Parameter transformations are now automatically
	performed when appropriate.  The default parameter
	transformation remains the identity.

    o   The old probe.match and traj.match functions have been removed.
	The new approach to parameter estimation based on numerical
	optimization involves constructing stateful objective
	functions.  There are now three of these: traj.match.objfun,
	probe.match.objfun, and spect.match.objfun.

    o   The documentation system has been thoroughly overhauled.

    o   In skeleton, the t argument has been replaced by times, to make
	this uniform with the other workhorse functions.

    o   Covariates are now included using the covariate_table
	construction, passed via the covar argument to pomp.  The
	tcovar argument is no longer used.

    o   Instead of providing separate fromEstimationScale and
	toEstimationScale arguments to pomp, one now provides a single
	partrans argument constructed by means of the new function
	parameter_trans.  In addition, references to
	“fromEstimationScale” and “toEstimationScale” have been
	abbreviated to “fromEst” and “toEst”, respectively, throughout
	the package.

    o   When writing C snippets for parameter transformations, the
	notation T_p refers to the value of p on the estimation scale.
	Thus, if parameter alpha is to be log-transformed for
	estimation, the toEst snippet would contain the line T_alpha =
	log(alpha); and the fromEst snippet would include alpha =
	exp(T_alpha);.

    o   The parameter_trans function now takes optional arguments log,
	logit, and barycentric, with names of parameters to be log-,
	logit-, and log-barycentric transformed, respectively.

    o   The measurement.model argument to pomp has been removed.  It is
	now necessary to specify the measurement model directly using
	rmeasure and/or dmeasure.

    o   The initializer is no longer referred to by that name.  It is
	now rinit, since it draws from the distribution of the latent
	state at the initial time.  The low-level function init.state
	has been replaced by rinit.

    o   The conv.rec method has been deprecated, replaced by the new
	traces method.

    o   The euler.sir example has been renamed sir.

    o   The gillespie.sir example has been renamed sir2.

    o   The covmat method can now be applied to a probed.pomp object.
	It returns the estimated covariance matrix of the probes.

    o   When trajectory calls on deSolve routines to numerically
	integrate a model vectorfield, more informative error messages
	are generated, and diagnostics are printed when verbose = TRUE.

    o   The show method applied to pomp objects is now quite terse.  To
	obtain detailed information, the spy method is available.

    o   The spy method now returns the information formerly displayed
	in a call to show, in addition to the C files associated with
	any C snippets.

    o   The use of $ methods to access the slots of pomp S4 objects has
	now been removed.  These classes are no longer exported (for
	the most part).

    o   The transform argument to the probe.quantile function has been
	removed (as it is entirely redundant!).

    o   The old and deprecated mif and bsmc methods have been removed.

                       Changes in version 1.18.8                        

    o   The obs and states arguments of simulate are deprecated and
	will be removed in a forthcoming release.

    o   The C-level interface for apply_probe_sims has changed: the new
	argument rho must be the “package:pomp” environment.

                       Changes in version 1.18.7                        

    o   A bug in pfilter (and hence pmcmc) when filter.traj=TRUE was
	discovered and fixed.  In the buggy version, the filter
	trajectory was sampled with incorrect weights.

    o   Timo Voipio contributed a pull request that traps the error
	resulting from sannbox being passed a candidate.dist that is
	not a function.

                       Changes in version 1.18.6                        

    o   show and print methods have been made very terse: they simply
	report on the class of the object in question.  To see more
	detailed information about a ‘pomp’ object, use spy.

    o   New (unexported) solibs<- method allows developers of packages
	extending pomp to incorporate C snippets into object that
	contain ‘pomp’ objects.

                       Changes in version 1.18.5                        

    o   New verbose option in trajectory gives diagnostic information
	from deSolve integration routines.  Of course, this is
	pertinent only if the model skeleton is a vectorfield.

    o   Bug in the display of istate when deSolve::ode errors has been
	fixed.

                       Changes in version 1.18.4                        

    o   New hitch function facilitates construction of pomp.fun objects
	from R functions, C snippets, and links to external libraries.

    o   Native routines needed to access pomp.fun objects in C are now
	registered for use by other packages.

    o   coef(object) <- NULL, where object is of class ‘pomp’, erases
	any parameters stored in object.

                       Changes in version 1.18.3                        

    o   The euler.sir, gillespie.sir, blowflies, ricker, bbs, dacca,
	and rw2 examples are all now implemented using C snippets.

    o   A new pomp_defines.h header is provided for developers of
	packages that depend on pomp.

    o   Internally, rprocess is no longer stored as an R function.  The
	use of plugins is now required for the implementation of the
	rprocess component.  Currently, there are five plugins
	available: onestep.sim, discrete.time.sim, euler.sim,
	gillespie.sim, and gillespie.hl.sim.

    o   The new hitch function automates the building and linking of C
	snippets and R functions into pomp.funs.

    o   The handling of dprocess has changed.  The onestep.dens plugin
	is now deprecated and will soon be removed.  dprocess is now
	specified directly using either a C snippet or an R function,
	in much the same way that, for example, dmeasure is specified.

    o   The old ‘forward’ and ‘inverse’ options for the dir argument of
	partrans have been dispensed with.  The much more descriptive
	options ‘toEstimationScale’ and ‘fromEstimationScale’ remain.

                       Changes in version 1.18.2                        

    o   The C snippet compiling facilities have been thoroughly
	reworked.

                       Changes in version 1.18.1                        

    o   onestep.dens can now take a Csnippet specification of the
	process-model transition density.

                       Changes in version 1.17.4                        

    o   All inference functions can now take a list in the start or
	params arguments.

                       Changes in version 1.17.3                        

    o   When altering parameters in a call to probe on a probed.pomp
	object, the new parameters were ignored.  This bug has been
	fixed.

    o   mif2, pfilter, probe, probe.match, and probe.match.objfun can
	now gracefully handle a list in the start or params arguments.

    o   New spy method displays the C snippet file(s) associated with a
	pomp object.

                       Changes in version 1.17.2                        

    o   The long-deprecated seed argument to bsmc and bsmc2 has been
	removed.

                       Changes in version 1.17.1                        

    o   More work to obviate warnings generated by T. Kalibera's latest
	rchk checks.

                       Changes in version 1.16.4                        

    o   Messages from the compiler resulting from attempts to compile C
	snippets are now suppressed on all platforms except in case of
	failure.  Setting verbose=TRUE forces display of these
	messages.

    o   Source codes have been revisited to obviate warnings generated
	by T. Kalibera's latest rchk checks.

                       Changes in version 1.16.3                        

    o   Fix a minor bugs in spect.

    o   Improve test coverage.

    o   spect.match has been refactored, with small changes to the
	interface.

    o   pomp now handles specification of workhorse functions (i.e.,
	rprocess, dprocess, rmeasure, dmeasure, initializer, skeleton,
	rprior, dprior, fromEstimationScale, toEstimationScale) as NULL
	more consistently.

                       Changes in version 1.16.2                        

    o   Fix bug in systematic resampler when np != nw.

    o   Fix bug in conv.rec when only one parameter is requested.

    o   Correct and improve documentation for conv.rec.

    o   coef<- can now take a list of parameters: it simply applies
	unlist to turn the list into a numeric vector.

    o   Simplify conv.rec.

                       Changes in version 1.16.1                        

    o   In pfilter, Np is now a required argument unless params is
	specified as a matrix of particles.  Thanks to Carles Breto for
	catching the unintended behavior.

                       Changes in version 1.15.4                        

    o   The bug reported in issue #57 has been fixed.

    o   A bug arising when building pomp objects with Csnippets in
	certain Windows configurations has been fixed.

                       Changes in version 1.15.3                        

    o   Issue #56, in which covariate names are discarded when coercing
	a pomp object to a data frame, has been fixed.  Thanks to Eamon
	O'Dea for reporting this bug.

    o   More informative error messages are given when bake or freeze
	return NULL.  In such a case, these functions now generate a
	warning and return a character-string message, with attributes.

    o   Improve documentation of traj.match, in response to Issue #57.

                       Changes in version 1.15.2                        

    o   A new facility, gillespie.hl.sim, allows implementation of
	Gillespie's algorithm for exact stochastic simulation of
	continuous-time Markov processes via a streamlined C snippet
	interface.

    o   The old facility for Gillespie simulations, gillespie.sim, now
	accepts C snippets for faster calculation of event rates.

    o   The old skeleton.type and skelmap.delta.t arguments of the pomp
	constructor, which have generated error messages since version
	1.9.2, have been done away with completely.

                       Changes in version 1.15.1                        

    o   Eamon O'Dea identified a bug (Issue #54) occurring when pomp is
	called with a single-row data frame.  This has been fixed using
	his contributed patch.

                       Changes in version 1.14.2                        

    o   A new dmultinom function is provided in ‘pomp.h’.  This
	provides the probability distribution function for the
	multinomial distribution.

                       Changes in version 1.14.1                        

    o   Improved tests.

    o   Fixed bugs emerging in R-devel due to refactoring of underlying
	R source code.

                       Changes in version 1.13.4                        

    o   Eamon O'Dea pointed out that the bug in gillespie.sim,
	addressed by version 1.12.3, was not completely fixed.  This
	problem has now been resolved.  In addition, covariates are now
	guaranteed to be evaluated at least once per observation
	interval.

    o   The new argument hmax to gillespie.sim allows the user to
	specify the maximum step size that will be taken before
	covariates are evaluated.

    o   The K-leap method has been removed.  Its accuracy is low on
	test problems and it is difficult to make it compatible with
	the pomp paradigm.  In particular, it does not readily
	accomodate time-varying covariates in a sensible way, nor does
	it lend itself to simulations at pre-specified times.

                       Changes in version 1.13.3                        

    o   bspline.basis and periodic.bspline.basis now take an optional
	non-negative integer argument deriv.  When deriv > 0, the
	order-deriv derivative of each basis function is returned.

    o   A new function, periodic_bspline_basis_eval_deriv, has been
	added to the C API.  This function gives access, at the C
	level, to evaluation of the derivatives of periodic B-splines.

                       Changes in version 1.13.2                        

    o   Upgrade license to GPL version 3.

                       Changes in version 1.13.1                        

    o   Fix buffer-flow problem identified by valgrind.

                       Changes in version 1.12.3                        

    o   Fix bug found by Eamon O'Dea in gillespie.sim.

    o   Fix bug in onestep.sim.

                       Changes in version 1.12.2                        

    o   The Ricker example has a new parameter, c, which scales the
	(unobserved) population size.  By default, c=1, so that the
	behavior is as before.

                       Changes in version 1.12.1                        

    o   Improved error trapping.

                       Changes in version 1.11.3                        

    o   Some changes have been made to the use of random numbers in
	some codes (the stochastic simulations in gillespie.sim and the
	resampling in the particle-filtering codes).  These changes
	will mean that calculations performed before will not be
	reproducible in perfect detail, but will be statistically
	equivalent.

    o   Minor changes in C codes to obviate warnings generated by T.
	Kalibera's rchk checks.

                       Changes in version 1.11.2                        

    o   The rare and fascinating “Bug of St. Patrick” has been fixed.
	Thanks to Carles Breto for finding the bug and helping to
	isolate it.

    o   More informative error messages are generated when dmeasure
	returns a non-finite likelihood in any of the particle
	filtering codes.

                       Changes in version 1.11.1                        

    o   Some streamlining of codes.

                       Changes in version 1.10.6                        

    o   Callable routines are now registered.

                       Changes in version 1.10.5                        

    o   More verbosity is provided with verbose=TRUE.

                       Changes in version 1.10.4                        

    o   The functions bake, stew, and freeze now preserve information
	about the system time used in computation as an attribute of
	the returned object.  In addition, these functions store
	information about the RNG settings.

    o   Some documentation improvements, courtesy of Sebastian Funk.

                       Changes in version 1.10.3                        

    o   Documentation improvements.

                       Changes in version 1.10.2                        

    o   More verbosity in building of Csnippets.

                       Changes in version 1.10.1                        

    o   Better handling of pomp's times argument.

                        Changes in version 1.9.3                        

    o   New logLik method for pmcmcList objects.

                        Changes in version 1.9.2                        

    o   The deprecated options to supply a matrix or numeric vector as
	the data argument to pomp have been removed and doing so now
	generates an error.  The first argument to pomp, data, must now
	be provided either as a data frame or as an object of class
	pomp.  See ?pomp for details.

    o   The deprecated skeleton.type and skelmap.delta.t arguments to
	pomp have been removed.  Using these arguments will now
	generate an error message.  The correct method of specifying
	the deterministic skeleton is now explained in the help pages
	(?pomp).

                        Changes in version 1.9.1                        

    o   Source code fixes to eliminate warnings during compilation.

    o   Improved test suite.

    o   Minor documentation correction.

                       Changes in version 1.8.11                        

    o   During particle filtering, when non-finite dmeasure values are
	generated, an error is generated and the offending parameters,
	states, data, and time are reported.  In methods that use
	parameter transformations (transform=TRUE), the reported
	parameters were on the transformed (estimation) scale, which
	can be confusing.  The error message now gives the parameters
	on the natural (model) scale.

    o   Modified src/ssa.c to fix UBSAN errors.

                       Changes in version 1.8.10                        

    o   C codes have been modified to take advantage of changes to the
	R API (R SVN REVISION 71180).

                        Changes in version 1.8.9                        

    o   A bug in mif2 arising when filtering fails in the final
	timestep has been fixed.  In this case, when all particles are
	deemed inconsistent with the data, we use an unweighted mean
	(with a warning) in place of the default weighted mean.

                        Changes in version 1.7.7                        

    o   The stochastic simulation algorithms underlying the Gillespie
	and K-leap methods (gillespie.sim, kleap.sim) have been
	refactored in C.  In addition, errors due to accumulation of
	round-off error have been repaired.  The result will be more
	accurate, but somewhat slower when there are a very large
	number of reactions.

    o   Further improvements to the test suite.  Code coverage is now
	100%.

                        Changes in version 1.7.6                        

    o   In Sobol' sequence generation (sobolDesign, profileDesign), we
	now use the suggestion of Joe & Kuo (2003) to choose a better
	sequence start point.

                        Changes in version 1.7.5                        

    o   The generation of Sobol' sequences (sobolDesign, profileDesign)
	is now performed using the NLopt routines written in C instead
	of the original TOMS 659 FORTRAN codes.  The copyright notices
	are located in the source code.

    o   Improved testing suite.

    o   Made rw.sd even more robust via new safecall class.

                        Changes in version 1.7.4                        

    o   Refactored rw.sd for greater stability.

                        Changes in version 1.7.3                        

    o   Fixed a bug in plot on pomp objects with more than 10 variables
	to plot.

    o   Added the shlib.args option to pomp, allowing arbitrary options
	to be passed to the compiler when C snippets are used.

    o   Modified the “dacca” example to use C snippets.

    o   Refactored rw.sd for greater stability.

    o   Made Sobol' codes more robust.

                        Changes in version 1.7.2                        

    o   Modified the demos to use best practices.

                        Changes in version 1.7.1                        

    o   Improved the test suite.

                        Changes in version 1.6.7                        

    o   Improve the test suite and error messages.

    o   Replace the automatic “verbose” setting during compilation
	under Windows.  This was dropped in version 1.6.4.3, when it no
	longer appeared to be necessary.  Apparently, it is, at least
	under some Windows OS/R combinations.

                        Changes in version 1.6.6                        

    o   Fix probe bug introduced in version 1.6.5.9.

                        Changes in version 1.6.5                        

    o   Several obscure bug-fixes.

    o   Improvement of the test suite and of error messages.

                        Changes in version 1.6.4                        

    o   Remove the automatic “verbose” setting during compilation under
	Windows.  This was introduced in version 0.63-6 as a
	workaround.  It appears no longer to be necessary.

    o   Improve the show method for pomp objects.

    o   Change the print method for pomp objects.

    o   Improve messages for plugin errors.

    o   Some internal refactoring.

                        Changes in version 1.6.3                        

    o   Improve error messages for missing basic components.

                        Changes in version 1.6.2                        

    o   Fix typos in one of the help-page examples.

    o   Add some references.

                        Changes in version 1.6.1                        

    o   Major revisions to the package help pages and manual.  The
	separate documentation on C snippets and process-model plugins
	has been merged into the main pomp help page, which now has
	comprehensive instructions on building a pomp object.

    o   Update to the package help page.

                       Changes in version 1.5.10                        

    o   The matrix and numeric vector options for the data argument to
	pomp are now deprecated and will be removed in a future
	release.  In calls to pomp, data should be either a data frame
	or a pomp-class object.

    o   Many more errors are now trapped and reported with more
	informative messages.

                        Changes in version 1.5.9                        

    o   Redundant bootstrap argument to nlf has been removed.

    o   More improvements to the testing suite.

                        Changes in version 1.5.8                        

    o   Major improvements to error and warning handling.

    o   Fix bugs that might arise in rare circumstances in simulate and
	eulermultinom functions.

    o   More improvements to the testing suite.

                        Changes in version 1.5.7                        

    o   Many improvements to the test suite.

    o   Fixed a bug in pompExample.

                        Changes in version 1.5.6                        

    o   Major overhaul of error handling system and error messages.

    o   There is a new plugin for rprocess called kleap.sim.  This
	implements the so-called “K-leap method” of Cai & Xu (2007).

                        Changes in version 1.5.5                        

    o   Many improvements to the test suite.

                        Changes in version 1.5.4                        

    o   More improvements to the test suite.

    o   Fixed bugs found as a result of improved testing.

    o   In mif2, it is now required that Nmif>0.

                        Changes in version 1.5.3                        

    o   More improvements to the test suite.

    o   Fixed bugs found as a result of improved testing.

    o   Fixed bug in specification of skeleton in pompExamples.

                        Changes in version 1.5.2                        

    o   Improved the test suite to obtain better code coverage.

    o   pomp is no longer an S4 method.  Its new status as an ordinary
	function abbreviates and consolidates the code and simplifies
	the documentation.

    o   Some minor improvements to error messages.

    o   A bug restricting access in C code to userdata has been fixed.

    o   Fixed bug in pompExample(...,show=TRUE).

                        Changes in version 1.5.1                        

    o   New methods for the Ensemble Kalman Filter (enkf) and Ensemble
	Adjustment Kalman Filter (eakf) have been added to the package.

                        Changes in version 1.4.9                        

    o   A better interface for specifying a model's deterministic
	skeleton is provided.  One specifies skeleton=map(f,delta.t)
	for a discrete-time skeleton (a map) and
	skeleton=vectorfield(f) for a continuous-time skeleton (a
	vectorfield).  The old arguments skeleton.type and
	skelmap.delta.t are deprecated and will be removed in a future
	release.

    o   The pfilter help page has been improved.  Specifically, the
	discussion of filtering failures is better.

    o   Miscellaneous improvements to the help pages.

                        Changes in version 1.4.8                        

    o   mif2 no longer computes filter means.

                        Changes in version 1.4.7                        

    o   The new argument show of pompExamples allows one to display the
	example code instead of executing it.

    o   The minimum version of R supported is now 3.1.2.

                        Changes in version 1.4.6                        

    o   init.state now has the optional argument nsim.  Using this, one
	can request multiple initial state vectors per parameter
	vector.

    o   pfilter now uses less memory when it is asked to run at a
	single point in parameter space.

                        Changes in version 1.4.5                        

    o   A bug associated with the rw.sd argument to mif2 on Windows
	platforms has been fixed.

                        Changes in version 1.4.4                        

    o   The method="mif2" option to mif has been removed.  Use mif2
	instead.

                        Changes in version 1.4.3                        

    o   The particles method (rarely if ever used), has been removed to
	streamline the mif codes.

                        Changes in version 1.4.2                        

    o   The method="mif2" option to mif is now deprecated.  It will be
	removed in a future release.  Use mif2 instead.

                        Changes in version 1.4.1                        

    o   Following the publication of the Journal of Statistical
	Software announcement paper, the CITATION has been modified to
	include the appropriate citation.  Please use citation("pomp")
	to learn about how to cite pomp correctly.

                        Changes in version 1.3.4                        

    o   conv.rec on the results of a mif2 computation now play nicely
	with reshape2::melt.

                        Changes in version 1.3.3                        

    o   It is now possible to direct pomp to place Csnippet codes in a
	specified location.  This is accomplished via the new cdir and
	cfile arguments to pomp.

                        Changes in version 1.3.2                        

    o   When several concurrent R processes attempt to simultaneously
	compile Csnipet code from copies of a pomp object on the same
	machine, a race condition exists.  This release fixes this by
	ensuring that Csnippet codes are written and compiled in a
	process-specific directory.

                        Changes in version 1.3.1                        

    o   The seed argument to pfilter has been removed.  Use freeze to
	obtain similar functionality.

    o   The redundant pars argument to mif has been removed.  Names of
	parameters to be estimated are taken from the nonzero entries
	of rw.sd.  Initial-value parameters are designated using the
	ivps argument.

    o   The old parameter.transform and parameter.inv.transform
	arguments to pomp have been removed.  They were superseded by
	the arguments fromEstimationScale and toEstimationScale in
	version 0.65-1.

                        Changes in version 1.2.2                        

    o   Some internal changes to mif2 by C. Breto, in support of panel
	methods under development.

                        Changes in version 1.2.1                        

    o   Bug fix: for POMPs with a scalar state variable, the
	filter.mean, pred.mean, and pred.var methods dropped the
	singleton dimension of the respective arrays, in conflict with
	the assumptions of certain plot methods.  This resolves issue
	#3.

                        Changes in version 1.1.4                        

    o   Documentation improvements.  Specifically, the details of how
	step-sizes are chosen in the euler.sim, discrete.time.sim, and
	onestep.sim plugins has been spelled out explicitly.  Also,
	incompleteness in the sannbox documentation has been corrected.

                        Changes in version 1.1.3                        

    o   Provide filter.traj method for pmcmcList objects.

                        Changes in version 1.1.2                        

    o   Fixed a bug in mif and mif2 when cooling.type="hyperbolic" and
	cooling.fraction.50=1.
