R: Image Plot for Sparse Matrices

SparseM.image {SparseM} | R Documentation

## Image Plot for Sparse Matrices

### Description

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

### Usage

    ## S4 method for signature 'matrix.csr'
    image(x, col=c("white","gray"),
          xlab="column", ylab="row", ...)

### Arguments

`x` | a matrix of class `matrix.csr`.

`col` | 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.

### 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)))

[Package SparseM version 1.77 Index]