In {ggm}

Indicator matrix

Description

Finds the indicator matrix of the zeros of a matrix.

Usage

In(A)

Arguments

A

a matrix.

Details

The indicator matrix is a matrix of zeros and ones which has a zero element iff the corresponding element of A is (exactly) zero.

Value

a matrix of the same dimensions as A.

Author(s)

Giovanni M. Marchetti

References

Wermuth, N. & Cox, D.R. (2004). Joint response graphs and separation induced by triangular systems. J.R. Statist. Soc. B, 66, Part 3, 687-717.

See Also

DAG, inducedCovGraph, inducedConGraph

Examples

## A simple way to find the overall induced concentration graph
## The DAG on p. 198 of Cox & Wermuth (1996)
amat <- DAG(y1 ~ y2 + y3, y3 ~ y5, y4 ~ y5)
A <- edgematrix(amat)
In(crossprod(A))