function [Cglob, comptime] = matmul_pct(size_A, size_B)
%===============================================================================
% MATLAB EXAMPLE: PARALLEL HELLO WORLD USING PCT TOOLBOX
% -> 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
%===============================================================================
% Verify that no parallel pool is initialized by creating/deleting a dummy pool
%===============================================================================
if ~isempty(gcp('nocreate'))
poolobj = gcp('nocreate');
delete(poolobj);
end
%===============================================================================
% Start parallel pool
%===============================================================================
% Get number of workers depending on job type. Start parallel pool via "local"
% cluster object.
%
% obtain number of tasks from Slurm environment variables
cluster = getenv('SLURM_CLUSTER_NAME');
if strcmp(cluster, 'inter')
% interactive job
nw = str2num(getenv('SLURM_JOB_CPUS_PER_NODE'));
elseif strcmp(cluster, 'cm2_tiny') || ...
strcmp(cluster, 'serial') || ...
strcmp(cluster, 'mpp3') || ...
strcmp(cluster, 'ivymuc')
% batch job
nw = str2num(getenv('SLURM_NTASKS'));
else
% default
nw = 1;
end
% disallow Threading
if maxNumCompThreads > 1
maxNumCompThreads(1);
warning('MultiThreading: number of threads has been set to 1!');
end
% create a local cluster object
pc = parcluster('local');
% set number of workers
pc.NumWorkers = nw;
% set the JobStorageLocation to SCRATCH (default: HOME -> not recommended)
pc.JobStorageLocation = strcat(getenv('SCRATCH'));
% start the parallel pool
poolobj = parpool(pc, nw);
%===============================================================================
% Work
%===============================================================================
spmd
fprintf('Hello from MATLAB process PID=%d running on node %s!\n',...
feature('getpid'),...
getenv('HOSTNAME'));
end
% 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 );
% distribute data to workers and do parallel computation
spmd
Aloc = codistributed(A, codistributor2dbc([nw 1]));
Bloc = codistributed(B, codistributor2dbc([1 nw]));
tic;
Cloc = Aloc*Bloc;
t = toc;
end
comptime = max(cell2mat(t(:)));
fprintf('parallel computation (MPI) of matrix-matrix product:\n');
fprintf('\tnumber of tasks (MATLAB workers) = %d\n', nw);
fprintf('\ttime = %.2f s\n', comptime);
Cglob = gather(Cloc);
%===============================================================================
% Close parallel pool
%===============================================================================
delete(poolobj); |