a list of colors such as that generated by rainbow.
Defaults to c("white","gray")
xlab,ylab
each a character string giving the labels for the x and y axis.
...
additional 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.
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)))