deSolve: DLLres – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

DLLres

Evaluates a Residual Derivative Function Represented in a DLL

Description

Calls a residual function, F(t,y,y') of a DAE system (differential algebraic equations) defined in a compiled language as a DLL.

To be used for testing the implementation of DAE problems in compiled code

Usage

DLLres(res, times, y, dy, parms, dllname,
  initfunc = dllname, rpar = NULL, ipar = NULL, nout = 0,
  outnames = NULL, forcings = NULL, initforc = NULL,
  fcontrol = NULL)

Arguments

`res`	the name of the function in the dynamically loaded shared library,
`times`	first value = the time at which the function needs to be evaluated,
`y`	the values of the dependent variables for which the function needs to be evaluated,
`dy`	the derivative of the values of the dependent variables for which the function needs to be evaluated,
`parms`	the parameters that are passed to the initialiser function,
`dllname`	a string giving the name of the shared library (without extension) that contains the compiled function or subroutine definitions referred to in `func`,
`initfunc`	if not NULL, the name of the initialisation function (which initialises values of parameters), as provided in ‘dllname’. See details,
`rpar`	a vector with double precision values passed to the DLL-function `func` and `jacfunc` present in the DLL, via argument `rpar`,
`ipar`	a vector with integer values passed to the DLL-function `func` and `jacfunc` present in the DLL, via function argument `ipar`,
`nout`	the number of output variables.
`outnames`	only used if ‘dllname’ is specified and `nout` > 0: the names of output variables calculated in the compiled function `func`, present in the shared library.
`forcings`	only used if ‘dllname’ is specified: a list with the forcing function data sets, each present as a two-columned matrix, with (time,value); interpolation outside the interval [min(`times`), max(`times`)] is done by taking the value at the closest data extreme. See package vignette `"compiledCode"`.
`initforc`	if not `NULL`, the name of the forcing function initialisation function, as provided in ‘dllname’. It MUST be present if `forcings` has been given a value. See package vignette `"compiledCode"`.
`fcontrol`	A list of control parameters for the forcing functions. See package vignette `"compiledCode"`.

Details

This function is meant to help developing FORTRAN or C models that are to be used to solve differential algebraic equations (DAE) in package deSolve.

Value

a list containing:

`res`	the residual of derivative estimated by the function
`var`	the ordinary output variables of the function

Author(s)

Karline Soetaert <karline.soetaert@nioz.nl>

Examples

## =========================================================================
## Residuals from the daspk chemical model, production a forcing function
## =========================================================================
## Parameter values and initial conditions
## see example(daspk) for a more comprehensive implementation

pars <- c(K = 1, ka = 1e6, r = 1)

## Initial conc; D is in equilibrium with A,B
y <- c(A = 2, B = 3, D = 2 * 3/pars["K"])

## Initial rate of change
dy <- c(dA = 0, dB = 0, dD = 0)

## production increases with time
prod <- matrix(ncol = 2,
          data = c(seq(0, 100, by = 10), seq(0.1, 0.5, len = 11)))

DLLres(y = y, dy = dy, times = 5, res = "chemres",
          dllname = "deSolve", initfunc = "initparms",
          initforc = "initforcs", parms = pars, forcings = prod,
          nout = 2, outnames = c("CONC", "Prod"))

deSolve

Solvers for Initial Value Problems of Differential Equations ('ODE', 'DAE', 'DDE')

v1.28

GPL (>= 2)

Authors

Karline Soetaert [aut] (<https://orcid.org/0000-0003-4603-7100>), Thomas Petzoldt [aut, cre] (<https://orcid.org/0000-0002-4951-6468>), R. Woodrow Setzer [aut] (<https://orcid.org/0000-0002-6709-9186>), Peter N. Brown [ctb] (files ddaspk.f, dvode.f, zvode.f), George D. Byrne [ctb] (files dvode.f, zvode.f), Ernst Hairer [ctb] (files radau5.f, radau5a), Alan C. Hindmarsh [ctb] (files ddaspk.f, dlsode.f, dvode.f, zvode.f, opdkmain.f, opdka1.f), Cleve Moler [ctb] (file dlinpck.f), Linda R. Petzold [ctb] (files ddaspk.f, dlsoda.f), Youcef Saad [ctb] (file dsparsk.f), Clement W. Ulrich [ctb] (file ddaspk.f)

Initial release