flow {pomp} | R Documentation |
flow workhorse
Description
Compute the flow generated by a deterministic vectorfield or map.
Usage
## S4 method for signature 'pomp'
flow(
object,
...,
x0,
t0 = timezero(object),
times = time(object),
params = coef(object),
verbose = getOption("verbose", FALSE)
)
Arguments
object |
an object of class ‘pomp’, or of a class that extends ‘pomp’.
This will typically be the output of |
... |
Additional arguments are passed to the ODE integrator (if the skeleton is a vectorfield) and are ignored if it is a map.
See |
x0 |
an array with dimensions |
t0 |
the time at which the initial conditions are assumed to hold.
By default, this is the zero-time (see |
times |
a numeric vector (length |
params |
a |
verbose |
logical; if |
Details
In the case of a discrete-time system (map), flow
iterates the map to yield trajectories of the system.
In the case of a continuous-time system (vectorfield), flow
uses the numerical solvers in deSolve to integrate the vectorfield starting from given initial conditions.
Value
flow
returns an array of dimensions nvar
x nrep
x ntimes
.
If x
is the returned matrix, x[i,j,k]
is the i-th component of the state vector at time times[k]
given parameters params[,j]
.
Accumulator variables
When there are accumulator variables (as determined by the accumvars
argument), their handling in the continuous-time (vectorfield) case differs from that in the discrete-time (map) case.
In the latter, accumulator variables are set to zero at the beginning of each interval ,
over which flow computation is required.
In the former, the flow computation proceeds over the entire set of intervals required, and accumulator variables are then differenced.
That is, the value
of accumulator variable
at times
,
will be
, where
is the solution of the corresponding differential equation at
.
See Also
More on pomp workhorse functions:
dinit()
,
dmeasure()
,
dprior()
,
dprocess()
,
emeasure()
,
partrans()
,
pomp-package
,
rinit()
,
rmeasure()
,
rprior()
,
rprocess()
,
skeleton()
,
vmeasure()
,
workhorses
More on methods for deterministic process models:
skeleton()
,
skeleton_spec
,
traj_match
,
trajectory()