function [h, array] = display_network(A, opt_normalize, opt_graycolor, cols, opt_colmajor)

% This function visualizes filters in matrix A. Each column of A is a

% filter. We will reshape each column into a square image and visualizes

% on each cell of the visualization panel. 

% All other parameters are optional, usually you do not need to worry

% about it.

% opt_normalize: whether we need to normalize the filter so that all of

% them can have similar contrast. Default value is true.

% opt_graycolor: whether we use gray as the heat map. Default is true.

% cols: how many columns are there in the display. Default value is the

% squareroot of the number of columns in A.

% opt_colmajor: you can switch convention to row major for A. In that

% case, each row of A is a filter. Default value is false.

warning off all

if ~exist('opt_normalize', 'var') || isempty(opt_normalize)

    opt_normalize= true;

end

if ~exist('opt_graycolor', 'var') || isempty(opt_graycolor)

    opt_graycolor= true;

end

if ~exist('opt_colmajor', 'var') || isempty(opt_colmajor)

    opt_colmajor = false;

end

% rescale

A = A - mean(A(:));

if opt_graycolor, colormap(gray); end

% compute rows, cols

[L M]=size(A);

sz=sqrt(L);

buf=1;

if ~exist('cols', 'var')

    if floor(sqrt(M))^2 ~= M

        n=ceil(sqrt(M));

        while mod(M, n)~=0 && n<1.2*sqrt(M), n=n+1; end

        m=ceil(M/n);

    else

        n=sqrt(M);

        m=n;

    end

else

    n = cols;

    m = ceil(M/n);

end

array=-ones(buf+m*(sz+buf),buf+n*(sz+buf));

if ~opt_graycolor

    array = 0.1.* array;

end

if ~opt_colmajor

    k=1;

    for i=1:m

        for j=1:n

            if k>M, 

                continue; 

            end

            clim=max(abs(A(:,k)));

            if opt_normalize

                array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/clim;

            else

                array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/max(abs(A(:)));

            end

            k=k+1;

        end

    end

else

    k=1;

    for j=1:n

        for i=1:m

            if k>M, 

                continue; 

            end

            clim=max(abs(A(:,k)));

            if opt_normalize

                array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz)/clim;

            else

                array(buf+(i-1)*(sz+buf)+(1:sz),buf+(j-1)*(sz+buf)+(1:sz))=reshape(A(:,k),sz,sz);

            end

            k=k+1;

        end

    end

end

if opt_graycolor

    h=imagesc(array,'EraseMode','none',[-1 1]);

else

    h=imagesc(array,'EraseMode','none',[-1 1]);

end

axis image off

drawnow;

warning on all