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Some quick 'n dirty matlab functions for working with graphs and their important matrices.
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function easygplot( A ) | |
%EASYGPLOT What gplot should do by default. | |
% EASYGPLOT puts all nodes on a circle equidistantly starting at (1, 0) | |
% and going counter clockwise. 2-way edges are plotted in black, edges | |
% from node i to node j with i < j are plotted in blue, and edges from | |
% node j to i with j > i are plotted in red. | |
% | |
% It's assumed that A(i,j) = 1 if there is an edge from j into i, and | |
% A(i,j) is zero otherwise. | |
% Parts where stolen from http://www.mathworks.nl/matlabcentral/fileexchange/16131-plot-a-directed-graph | |
n = size(A, 1); | |
t = linspace(0, 2*pi, n + 1); | |
coords = [cos(t(1:n))' sin(t(1:n))']; | |
dA = A .* (1 - A'); % Directed edges (1-way) | |
dAl = tril(dA, -1); % Directed edges (1-way, i -> j with i < j) | |
dAu = triu(dA, 1); % directed edges (1-way, j -> i with j > i) | |
uA = A - dA; % Undirected edges (2-way, i -> j and j -> i) | |
figure(); % Open a new figure every time. | |
gplot(uA, coords, '-k'); | |
hold on; | |
gplot(dAl, coords, '-b'); | |
gplot(dAu, coords, '-r'); | |
hold off; | |
end |
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function mat2tex( matrix, varargin ) | |
%MAT2TEX Print a matrix in TeX format. | |
% MAT2TEX allows you to print a matrix to (La)TeX. It outputs the | |
% matrix as a \begin{env}...\end{env} block, where env defaults to | |
% pmatrix. Each element of the matrix is printed in a supplied fmt | |
% which is '%d' by default. | |
if nargin > 2 | |
env = varargin{1}; | |
fmt = varargin{2}; | |
elseif nargin == 2 | |
env = varargin{1}; | |
fmt = '%d'; | |
else | |
env = 'pmatrix'; | |
fmt = '%d'; | |
end | |
fprintf('\n\\begin{%s}\n', env); | |
[n,m] = size(matrix); | |
for i = 1:n | |
fprintf(' '); | |
for j = 1:m | |
fprintf(fmt, matrix(i,j)); | |
if j < m | |
fprintf(' %s ', '&'); | |
end | |
end | |
if i < n | |
fprintf(' %s', '\\'); | |
end | |
fprintf('\n'); | |
end | |
fprintf('\\end{%s}\n\n', env); | |
end |
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