SPY  SPY Visualize Sparsity Pattern of a Sparse Matrix


Usage
 
 Plots the sparsity pattern of a sparse matrix.  The syntax for its use is
 
    spy(x)
 
 which uses a default color and symbol.  Alternately, you can use
 
    spy(x,colspec)
 
 where colspec is any valid color and symbol spec accepted by plot.
 