function y = unspar(x, realFlag)

% unspar -- Convert "spar" array to "sparse".
%  unspar(x) converts the "spar" array x
%   to a Matlab "sparse" array, if the data
%   represent a two-dimensional array; otherwise,
%   to a "full" array.  See "help spar".
%  unspar(x, realFlag) assumes that x lacks the
%   imaginary-component column, if realFlag is TRUE.
%  NOTE: a complex-array will be auto-detected, so
%   long as the next-to-last column contains values
%   that would be invalid as indices.
 
% Copyright (C) 1999 Dr. Charles R. Denham, ZYDECO.
%  All Rights Reserved.
%   Disclosure without explicit written consent from the
%    copyright owner does not constitute publication.
 
% Version of 19-Aug-1999 14:30:00.
% Updated    24-Aug-1999 11:34:47.

if nargin < 1, help(mfilename), return, end
if nargin < 2, realFlag = 0; end

[m, n] = size(x);

if realFlag
	valid_indices =...
			isfinite(x(:, end-1)) & ...
			(x(:, end-1) > 0) & ...
			(x(:, end-1) == fix(x(:, end-1)));
	if ~all(valid_indices), realFlag = 0; end
end

if ~realFlag
	dim = n-2;
else
	dim = n-1;
end

siz = zeros(1, dim);
sub = cell(1, dim);
for j = 1:dim
	dat = x(:, j);
	siz(j) = max(dat);
	sub{j} = dat;
end
ind = sub2ind(siz, sub{:});

if dim == 2
	if ~realFlag
		result = sparse(sub{1}, sub{2}, x(:, end-1) + sqrt(-1) * x(:, end));
	else
		result = sparse(sub{1}, sub{2}, x(:, end));
	end
else
	result = zeros(siz);
	if ~realFlag
		result(ind) = x(:, end-1) + sqrt(-1) * x(:, end);
	else
		result(ind) = x(:, end);
	end
end

if nargout > 0
	y = result;
else
	disp(result)
	assignin('caller', 'ans', result)
end