25 lines
822 B
Matlab
25 lines
822 B
Matlab
function matrixbox( m )
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% visualizes the effect of a matrix m on a set of vectors forming a box
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% m: a 2x2 matrix
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v = [ 0 1 1 0 0; 0 0 1 1 0];
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w = m*v;
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clf;
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hold on;
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%set(gca, 'Xtick', [], 'Ytick', [], 'box', 'off')
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% axis:
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plot( [-2 2], [0 0], 'k', 'LineWidth', 1 );
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plot( [0 0], [-2 2], 'k', 'LineWidth', 1 );
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% old box:
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plot( v(1,:), v(2,:), 'k', 'LineWidth', 1.0 )
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quiver( [v(1,1)], [v(2,1)], [v(1,3)], [v(2,3)], 1.0, 'k', 'LineWidth', 2.0 );
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scatter( [v(1,2)], [v(2,2)], 60.0, 'filled', 'k' );
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% transfomred box:
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plot( w(1,:), w(2,:), 'b', 'LineWidth', 2.0 )
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quiver( [w(1,1)], [w(2,1)], [w(1,3)], [w(2,3)], 1.0, 'b', 'LineWidth', 3.0 );
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scatter( [w(1,2)], [w(2,2)], 100.0, 'filled', 'b' );
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hold off;
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xlim( [ -2 2 ] );
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ylim( [ -2 2 ] );
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end
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