LDEsysMat {nlme} | R Documentation

## Generate system matrix for LDEs

### Description

Generate the system matrix for the linear differential equations determined by a compartment model.

### Usage

    LDEsysMat(pars, incidence)

### Arguments

`pars` | a numeric vector of parameter values.
`incidence` | an integer matrix with columns named `From`, `To`, and `Par`. Values in the `Par` column must be in the range 1 to `length(pars)`. Values in the `From` column must be between 1 and the number of compartments. Values in the `To` column must be between 0 and the number of compartments.

### Details

A compartment model describes material transfer between `k` in a system of `k` compartments to a linear system of differential equations. Given a description of the system and a vector of parameter values this function returns the system matrix.

This function is intended for use in a general system for solving compartment models, as described in Bates and Watts (1988).

### Value

A `k` by `k` numeric matrix.

### Author(s)

Douglas Bates bates@stat.wisc.edu

### References

Bates, D. M. and Watts, D. G. (1988), Nonlinear Regression Analysis and Its Applications, Wiley, New York.

### Examples

    # incidence matrix for a two compartment open system
    incidence <-
      matrix(c(1,1,2,2,2,1,3,2,0), ncol = 3, byrow = TRUE,
       dimnames = list(NULL, c("Par", "From", "To")))
    incidence
    LDEsysMat(c(1.2, 0.3, 0.4), incidence)

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