spy (MATLAB Functions)

Visualize sparsity pattern

Syntax

spy(S)
spy(S,markersize)
spy(S,'LineSpec')
spy(S,'LineSpec',markersize)

Description

spy(S) plots the sparsity pattern of any matrix S.

spy(S,markersize), where markersize is an integer, plots the sparsity pattern using markers of the specified point size.

spy(S,'LineSpec'), where LineSpec is a string, uses the specified plot marker type and color.

spy(S,'LineSpec',markersize) uses the specified type, color, and size for the plot markers.

S is usually a sparse matrix, but full matrices are acceptable, in which case the locations of the nonzero elements are plotted.

Note spy replaces format +, which takes much more space to display essentially the same information.

Examples

This example plots the 60-by-60 sparse adjacency matrix of the connectivity graph of the Buckminster Fuller geodesic dome. This matrix also represents the soccer ball and the carbon-60 molecule.

```
B = bucky;
spy(B)
```

See Also

find, gplot, LineSpec, symamd, symmmd, symrcm

sprintf sqrt