function mtype = mwrite (filename, A, Z, comments_filename)		    %#ok
%MWRITE write a matrix to a file in Matrix Market form.
%
%   Example:
%        mtype = mwrite (filename, A, Z, comments_filename)
%
% A can be sparse or full.
%
% If present and non-empty, A and Z must have the same dimension.  Z contains
% the explicit zero entries in the matrix (which MATLAB drops).  The entries
% of Z appear as explicit zeros in the output file.  Z is optional.  If it is
% an empty matrix it is ignored.  Z must be sparse or empty, if present.
% It is ignored if A is full.
%
% filename is the name of the output file.  comments_filename is the file
% whose contents are include after the Matrix Market header and before the
% first data line.  Ignored if an empty string or not present.
%
% Known issue:  this function can fail if the file exceeds your filesystems
% filesize limitation.  On one 32bit flavor of Linux with a 2GB filesize
% limitation, the failure causes MATLAB to terminate immediately.  This happens
% with one matrix in the UF Sparse Matrix Collection: vanHeukelum/cage15, with
% about 99e6 nonzero entries and a dimension of over 5e6.  mwrite checks error
% conditions as approprate, but this particular error does not seem to be thrown
% properly and thus cannot be caught and dealt with.
%
% See also mread.

% Copyright 2006, Timothy A. Davis

error ('mwrite mexFunction not found') ;