function [r1,r2] = listvals(A,plotflag)
% LISTVALS  List the values in an array, and how many times they occur
%   M = LISTVALS(A) Returns a list of the values in the array A, and
%   the number of times they occur.  The first column of M contains a
%   list of the values in the array A, sorted into ascending order,
%   and the second column of M contains the number of times each value occurs.
%   That is, the value M(i,1) occurs in the array A M(i,2) times.
%   You can use the form [VALS,COUNTS] = LISTVALS(A) to get the values
%   and their counts as two separate return values.
%   Finally, if you give a second argument which is not zero, LISTVALS
%   will make a bar plot of the values and their counts.  E.g. LISTVALS(A,1);.
%
% Written by David Hiebeler, http://www.math.umaine.edu/faculty/hiebeler


tmpA = A(:)';  % if A is multidimensional, convert it into a 1D row vector
retval = [];  % start with empty array

while (size(tmpA, 2) ~= 0)   % while we still have some elements left
  % find minimum of remaining elements
  minval = min(tmpA);

  % see how many times it appears in the array
  mincount = sum(tmpA == minval);

  % add this info to return value
  retval = [retval ; minval mincount];

  % now remove all copies of minval from array
  tmpA = tmpA(find(tmpA ~= minval));
end

if (nargout == 2)
  r1 = retval(:,1);
  r2 = retval(:,2);
else
  r1 = retval;
end

if (nargin == 2)
  if (plotflag)
    bar(retval(:,1), retval(:,2))
  end
end