Image Plot for Sparse Matrices

Description

Display the pattern of non-zero entries of a matrix of class matrix.csr or matrix.csc

Usage

image(x, ...)

Arguments

Details

The pattern of the non-zero entries of a sparse matrix is displayed. By default nonzero entries of the matrix appear as gray blocks and zero entries as white background.

References

Koenker, R and Ng, P. (2002). SparseM: A Sparse Matrix Package for R,
http://www.econ.uiuc.edu/~roger/research

See Also

SparseM.ops, SparseM.solve, SparseM.ontology

Examples

a <- rnorm(20*5)
A <- matrix(a,20,5)
A[row(A)>col(A)+4|row(A)<col(A)+3] <- 0
b <- rnorm(20*5)
B <- matrix(b,20,5)
B[row(A)>col(A)+2|row(A)<col(A)+2] <- 0
image(as.matrix.csr(A)%*%as.matrix.csr(t(B)))