[SciPy-user] Problem with plot

[John Hunter]

On Tue, Mar 11, 2008 at 3:50 AM, Michael Nandris
<mnandris at btinternet.com> wrote:
> from numpy import matrix
> from scipy.linalg import inv, det, eig
> from pylab import plot, show


The plotting function spy should help (plot is designed to plot line
data).  See also imshow for 2D array plotting


    def spy(self, Z, precision=None, marker=None, markersize=None,
                                    aspect='equal', **kwargs):
        """
        spy(Z) plots the sparsity pattern of the 2-D array Z

        If precision is None, any non-zero value will be plotted;
        else, values of absolute(Z)>precision will be plotted.

        The array will be plotted as it would be printed, with
        the first index (row) increasing down and the second
        index (column) increasing to the right.

        By default aspect is 'equal' so that each array element
        occupies a square space; set the aspect kwarg to 'auto'
        to allow the plot to fill the plot box, or to any scalar
        number to specify the aspect ratio of an array element
        directly.

        Two plotting styles are available: image or marker. Both
        are available for full arrays, but only the marker style
        works for scipy.sparse.spmatrix instances.

        If marker and markersize are None, an image will be
        returned and any remaining kwargs are passed to imshow;
        else, a Line2D object will be returned with the value
        of marker determining the marker type, and any remaining
        kwargs passed to the axes plot method.

        If marker and markersize are None, useful kwargs include:
            cmap
            alpha
        See documentation for imshow() for details.
        For controlling colors, e.g. cyan background and red marks, use:
            cmap = mcolors.ListedColormap(['c','r'])

        If marker or markersize is not None, useful kwargs include:
            marker
            markersize
            color
        See documentation for plot() for details.

        Useful values for marker include:
            's'  square (default)
            'o'  circle
            '.'  point
            ','  pixel

        """