omxGetRAMDepth {OpenMx} | R Documentation |

## omxGetRAMDepth

### Description

Get the potency of a matrix for inversion speed-up

### Usage

```
omxGetRAMDepth(A, maxdepth = nrow(A) - 1)
```

### Arguments

`A` |
MxMatrix object |

`maxdepth` |
Numeric. maximum depth to check |

### Details

This function is used internally by the mxExpectationRAM function
to determine how far to expand `(I-A)^{-1} = I + A + A^2 + A^3 + ...`

. It is
similarly used by mxExpectationLISREL in expanding `(I-B)^{-1} = I + B + B^2 + B^3 + ...`

.
In many situations `A^2`

is a zero matrix (nilpotent of order 2). So when `A`

has large
dimension it is much faster to compute `I+A`

than `(I-A)^{-1}`

.

[Package

*OpenMx*version 2.21.11 Index]