R: Get Omega^-1 and derivatives

rxSymInvChol {RxODE} | R Documentation

## Get Omega^-1 and derivatives

### Description

Get Omega^-1 and derivatives

### Usage

    rxSymInvChol(
      invObjOrMatrix,
      theta = NULL,
      type = "cholOmegaInv",
      thetaNumber = 0L
    )

### Arguments

`invObjOrMatrix` | Object for inverse-type calculations. If this is a matrix, setup the object for inversion by `rxSymInvCholCreate` with the default arguments and return a reactive s3 object. Otherwise, use the inversion object to calculate the requested derivative/inverse.
`theta` | Thetas to be used for calculation. If missing (`NULL`), a special s3 class is created and returned to access Omega^1 objects as needed and cache them based on the theta that is used.
`type` | The type of object. Currently the following types are supported: `cholOmegaInv` gives the Cholesky decomposition of the Omega Inverse matrix. `omegaInv` gives the Omega Inverse matrix. `d(omegaInv)` gives the d(Omega^-1) withe respect to the theta parameter specified in `thetaNumber`. `d(D)` gives the d(diagonal(Omega^-1)) with respect to the theta parameter specified in the `thetaNumber` parameter
`thetaNumber` | For types `d(omegaInv)` and `d(D)`, the theta number that the derivative is taken against. This must be positive from 1 to the number of thetas defining the Omega matrix.

### Value

Matrix based on parameters or environment with all the matrixes calculated in variables omega, omegaInv, dOmega, dOmegaInv.

### Author(s)

Matthew L. Fidler

[Package RxODE version 0.9.1-9 Index]