Changes between Version 2 and Version 3 of cypress/Matlab

Timestamp:

08/13/15 16:08:14 (9 years ago)

Author:

fuji

Comment:

—

cypress/Matlab

@@ -63 +63 @@
 
 === Running MATLAB in Parallel with Multithreads ===
+MATLAB supports multithreaded computation for a number of functions and expressions that are combinations of element-wise functions.
+These functions automatically execute on multiple threads if data size is large enough. 
+Note that on Cypress, in default, MATLAB runs with a single threads, and you have to explicitly specify the number of threads in your code. 
+For example,
+{{{#!matlab
+% Matlab Test Code "FuncTest.m"
+%
+LASTN = maxNumCompThreads(str2num(getenv('SLURM_JOB_CPUS_PER_NODE')));
+nth = maxNumCompThreads;
+fprintf('Number of Threads = %d.\n',nth);
 
-=== Running MATLAB with Automatic Offloading ===
+N=2^(14);
+A = randn(N);
+st = cputime;
+tic;
+B = sin(A);
+realT = toc;
+cpuT = cputime -st;
+fprintf('Real Time = %f(sec)\n',realT);
+fprintf('CPU Time = %f(sec)\n',cpuT);
+fprintf('Speedup Factor = %f\n',cpuT / realT);
+}}}
+
+In above code, the line,
+{{{#!matlab
+LASTN = maxNumCompThreads(str2num(getenv('SLURM_JOB_CPUS_PER_NODE')));
+}}}
+defines the number of threads. 
+The environmental variable, '''SLURM_JOB_CPUS_PER_NODE''' has the value set in SLURM script, for example,
+{{{#!bash
+#!/bin/bash
+#SBATCH --qos=normal            # Quality of Service
+#SBATCH --job-name=matlabMT     # Job Name
+#SBATCH --time=1:00:00          # WallTime
+#SBATCH --nodes=1               # Number of Nodes
+#SBATCH --ntasks-per-node=1     # Number of tasks (MPI processes)
+#SBATCH --cpus-per-task=10      # Number of threads per task (OMP threads)
+
+module load matlab
+matlab -nodesktop -nodisplay -nosplash -r "FuncTest; exit;"
+}}}
+The number of cores per process (task) is set by '''--cpus-per-task=10'''. 
+This value goes to '''SLURM_JOB_CPUS_PER_NODE''' and you can use it to determine the number of threads used in the code.
 
 
+==== Explicit parallelism ====
+The ''parallel computing toolbox'' is available on Cypress. 
+You can use up to 12 workers for shared parallel operations on a single node in the current MATLAB version. 
+Our license does not include MATLAB Distributed Computing Server. Therefore, multi-node parallel operations are not supported.
+
+
+ 
+=== Running MATLAB with Automatic Offloading ===