Finds the indicator matrix of the zeros of a matrix.
Usage
In(A)
Arguments
A
a matrix.
Value
a matrix of the same dimensions as A.
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.
References
Wermuth, N. & Cox, D.R. (2003). Joint response graphs
and separation induced by triangular systems. Submitted and available at
http://psystat.sowi.uni-mainz.de.
## A simple way to find the overall induced coincentration graph## The DAG on p. 198 of Cox & Wermuth (1996)A <- DAG(y1 ~ y2 + y3, y3 ~ y5, y4 ~ y5)
In(crossprod(A))