The revisions let you track differences between multiple versions of a post.

Table of Contents

Matrices in OpenMx must be one of:

m11 | NA | NA |

NA | m22 | NA |

NA | NA | m33 |

m11 | m21 | m31 |

m21 | m22 | m32 |

m31 | m32 | m33 |

1 | 0 | 0 |

0 | 1 | 0 |

0 | 0 | 1 |

**Lower**

m11 | NA | NA |

m21 | m22 | NA |

m31 | m32 | m33 |

**Stand** (symmetric, ones on diagonal)

1 | m21 | m31 |

m21 | 1 | m32 |

m31 | m32 | 1 |

**Sdiag** (the sub-diagonal lower matrix)

NA | NA | NA |

m21 | NA | NA |

m31 | m32 | NA |

m11 | m21 | m31 |

m21 | m22 | m32 |

m31 | m32 | m33 |

1 | 0 | 0 |

0 | 1 | 0 |

0 | 0 | 1 |

0 | 0 | 0 |

0 | 0 | 0 |

0 | 0 | 0 |

require(OpenMx) A <- <strong>mxMatrix</strong>('Full', 1, 1, values = 1, name = 'A') B <- <strong>mxMatrix</strong>('Full', 1, 1, values = 2, name = 'B') C <- <strong>mxMatrix</strong>('Full', 1, 1, values = 3, name = 'C') D <- <strong>mxMatrix</strong>('Full', 3, 1, labels = c('A[1,1]', 'B[1,1]', 'C[1,1]'), name = 'D') model <- <strong>mxModel</strong>('model', A, B, C, D) fit <- <strong>mxRun</strong>(model) mxEval(D, fit)

A <- <strong>mxMatrix</strong>('Full', 2, 2, values = c(1,2,3,4), byrow = TRUE, name = 'A') B <- <strong>mxAlgebra</strong>(A + A, name = 'B') C <- <strong>mxMatrix</strong>('Full', 2, 2, labels = c('B[2,2]', 'B[2,1]', 'B[1,2]', 'B[1,1]'), byrow = TRUE, name = 'C') model <- <strong>mxModel</strong>('model', A, B, C) fit <- <strong>mxRun</strong>(model) mxEval(C, fit)

myMatrix <- mxMatrix('Full', 3, 5) nrow(myMatrix) ncol(myMatrix)

This feature allows you to construct MxMatrix objects, the labels of which refer to another MxMatrix or MxAlgebra. This is done by specifying the name, row, and col of the target matrix or algebra as you would expect to be able to in R, i.e., "foo[row,col]".

The effect of pointing to another cell using bracket notation is just the same as setting the label of the two cells to the same value.

So, given a matrix A with labels:

aLabels = c( "a1", "a2", "a3", "a4" )

Setting the labels of matrix B to this:

bLabels = c( "a1", "b2", "b3", "b4" )

Is the same as setting the labels of matrix B to this:

bLabels = c( "A[1,1]", "b2", "b3", "b4" )

Both methods forces cell B[1,1] to take the same value as A[1,1].

the benfit of the [] syntax is that you only need to set one label to equate two cells, and you don't need to know what label the other cell has currently, just its location.

Please add material here as you learn...

If you have questions not answers, then add those here: That's how a wiki works.

- Login or register to post comments
- Printer-friendly version
- Login or register to post comments
- Send to friend