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version (5.82 KB) by Hugo Gualdron
cspy: a color-coded version of sparse matrix viewer spy


Updated 06 Jun 2014

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Editor's Note: This file was selected as MATLAB Central Pick of the Week

cspy Visualize sparsity pattern.
cspy(S) plots the sparsity pattern of the matrix S with L levels where
L by default is number of integers between min matrix value and max
matrix value .

cspy(S,'Marker', '*') use the this marker to plot the matrix S.

cspy(S, 'Marker', {'*', '+'}) use each marker per level in the same
order. The size of the marker cell array must be equal to the number of
levels, in otherwise is used the first marker for all levels.

cspy(S,'MarkerSize', M) use the M markersize to plot the matrix S.

cspy(S, 'Levels', L) use L levels to show different colors in the
matrix S. If the levels is a vector and has the same size to channels
is used one value for channel. Where level hasn't the same size is used
the mean value.

cspy(S, 'ColorMap', 'hot') use this model color to assign the colors.
By default the colormap is 'lines'.

cspy(S, 'XDir', 'Reverse') change the X direction (Reverse or Normal).
Default Normal

cspy(S, 'YDir', 'Reverse') change the Y direction (Reverse or Normal).
Default Reverse

cspy(S, 'Channels', 'on') use the channel value ('on' or 'off' ) for
plot the images channels in different subplots (rgb for example) or
where the matrix is n x m x c where c are the channels. if the channels
value is 'off' and the matrix has c channels with c different to 3(rgb)
the channels value is changed to 'on'.

rgb = imread('ngc6543a.jpg');
cspy(rgb, 'marker', '.', 'markersize', 5, 'colormap', 'hot');
rgb = imread('ngc6543a.jpg');
cspy(rgb, 'marker', '.', 'markersize',5, 'colormap', 'hot', 'levels', 18);
rgb = imread('ngc6543a.jpg');
cspy(rgb, 'marker', '.', 'markersize',5, 'colormap', 'hot', 'levels', 18, 'channels', 'on');
rgb = imread('ngc6543a.jpg');
cspy(rgb, 'marker', '.', 'markersize',5, 'colormap', 'lines', 'levels', [2 15 3], 'channels', 'on');
rgb = imread('ngc6543a.jpg');
cspy(rgb, 'marker', {'.', '+', '*'}, 'markersize',5, 'colormap', 'lines', 'levels', 3, 'channels', 'off');

Hugo Gualdron -
Jose Rodrigues -
University of São Paulo

Cite As

Hugo Gualdron (2021). cspy.m (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (4)

Roman Kandinskii

Luca Freilino

Alceu Costa


Plots colorful spy plots, thank you!

MATLAB Release Compatibility
Created with R2011b
Compatible with any release
Platform Compatibility
Windows macOS Linux

Inspired: spy3D

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