function [C, comptime] = matmul_serial(size_A, size_B)
 
%===============================================================================
% MATLAB EXAMPLE: SERIAL HELLO WORLD
%                 -> matrix-matrix multiplication C = A*B
%
% INPUT
%   size_A, size_B ... 2-element row vectors defining sizes of A and B
% OUTPUT
%   C ................ result
%   comptime ......... computation time (matrix product only)
%===============================================================================
 
%===============================================================================
% Check input
%===============================================================================
if nargin~=2
    error('Invalid number of input arguments!');
end
if size_A(2)~=size_B(1)
    error(sprintf('Dimension mismatch of A (%d columns) and B (%d rows)!',...
                  size_A(2), size_B(1)));
end
 
%===============================================================================
% Work
%===============================================================================
% Hello message from compute node
fprintf('Hello from MATLAB process PID=%d running on node %s!\n',...
        feature('getpid'),...
        strtrim(evalc('system(''hostname'');')));
 
% generate well-defined matrices
NA = prod(size_A);
NB = prod(size_B);
A = reshape( linspace( 1,NA, NA), size_A );
B = reshape( linspace(NB, 1, NB), size_B );
 
% compute
tic;
C = A*B;
comptime = toc;
fprintf('serial computation of matrix-matrix product:\n');
fprintf('\ttime = %.2f s\n', comptime);