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To download COMSOL Multiphysics ® or COMSOL Server™, please log into your COMSOL Access account. You will need an on-subscription COMSOL license attached to your COMSOL Access account or a software trial provided by your sales representative. Trial licenses are automatically associated with your account. COMSOL Multiphysics The COMSOL Multiphysics engineering simulation software environment facilitates all steps in the modelling process − defining your geometry, meshing, specifying your physics, solving, and then visualizing your results. COMSOL provides software solutions for multiphysics modelling. Through CMC, you can access the following. COMSOL Multiphysics 5.6 Overview. A powerful simulation software for electrical engineering projects. The program can is designed to chemistry jobs, astronomy, quantum, earth sciences as well as mac erics. For the nonlinear systems, COMSOL Multiphysics 5.4 Full Crack lets you solve its equations with simple easier tools. Complex multiphysics coupling in complex geometry. For instance, Navier-Stokes equations, energy and species conservations equations for example see references 19, 20. The present simulation for the convective flow field, driven by both thermal/solutal buoyancy forces, is carried out by means of COMSOL Multiphysics package.

Problem Description

This solution describes how COMSOL takes advantage of multicore computers.

Solution

COMSOL supports two mutual modes of parallel operation: shared-memory parallelism and distributed-memory parallelism (cluster support). Shared-memory parallelism is supported with all COMSOL license types, while distributed-memory parallelism requires a floating network license. Using shared-memory parallelism is possible to utilize all CPU sockets on a computer, but for computers with multiple sockets, it can sometimes be advantageous with a floating network license to utilize the computer's full capacity; for further information, please see Hybrid Computing: Advantages of Shared and Distributed Memory Combined. This solution is dedicated to shared-memory parallel operations. For distributed-memory parallel operations, see Solution 1001.

Shared-memory processing, or multithreading is important for the performance of COMSOL computations. Some terms that are frequently used in when describing multithreading are

• Core: A physical processor core used in shared-memory parallelism by a computational node with multiple processors.
• Speedup: is how many times faster a job runs on N cores compared to 1 core, on a specific compute node. The speedup depends both on the problem type, the hardware used, and hardware drivers used.

Windows

On Windows platforms, the default number of processor cores used by COMSOL is the total number of available physical cores. For example, if you have a 2 x dual core machine, 4 cores will be used in parallel by a COMSOL Multiphysics process by default.

If you want COMSOL to leave out one or more processor cores you can manually set the number of cores used for a job, you can change the default behavior by starting the COMSOL Desktop and setting the Number of processors option on the Multicore and Cluster Computing section in the Preferences menu.

Alternatively, create a new shortcut on your Desktop to the COMSOL executable and modify it to set the desired number of threads.

1. Create a new shortcut on the Desktop.
2. Right-click the shortcut and select Properties.
3. Change the Target field to
   'C:Program FilesCOMSOLCOMSOL55Multiphysicsbinwin64comsol.exe' -np 2
   if you want COMSOL to use only 2 cores.

Mac OS X

Wacker dpu manual. On Mac OS X, controlling the number of processor cores used by COMSOL is only possible when launching COMSOL from the Terminal. The default behavior is to use all available physical processor cores for the COMSOL Multiphysics application. You can find how many processor cores you have in the System Profiler application, or by using the command sysctl hw.ncpu. You can override the default behavior by using the command line switches. For example, start by the command
/Applications/COMSOL55/Multiphysics/bin/comsol -np 2.

Linux

The number of cores available to a COMSOL process in parallel can be displayed on some systems by the command
more /proc/cpuinfo grep proc

Note that if you have hyperthreading activated you need to divide the cores count reported by the above command by relevant hyperthreading factor (2) to get the physical core count. COMSOL does not benefit from hyperthreading; if COMSOL is started with more threads than there are physical CPU cores, performance will decrease.

Comsol Multiphysics Mac Software

On Linux the default behavior is to use all available physical cores for the COMSOL Multiphysics application. You can override the default behavior by using the command line switches. For example, start by the command comsol -np 2.

Hyperthreading

COMSOL does currently not benefit from hyperthreading. COMSOL will use only as many threads as there are physical CPU cores on the system. The result is that if hyperthreading is active, the Windows Task Manager will show at most 50% CPU utilization for the COMSOL process. This is expected and not an indication that CPU utilization is too low. It is recommended to have hyperthreading enabled such that other applications running simultaneously can take advantage of it.

The -mpmode option

The values 'turnaround' and 'throughput' for -mpmode correlate directly with the OpenMP runtime settings for the KMPLIBRARY environment variable. The -mpmode option overwrites the system settings (if KMPLIBRARY is not set). For more information on the turnaround and throughput modes, please see the section on 'Execution modes' on https://software.intel.com/en-us/node/522689.​
All options use KMP_BLOCKTIME = 200 by default. turnaround is also the default, when -mpmode is not set at all. The 'serial' mode is not used by COMSOL. The third value that COMSOL lists for -mpmode is 'owner'. The owner option is similar to turnaround, the difference is that owner also specifies a thread affinity that is optimized for the number of sockets on the computer, so owner is more aggressive than turnaround.

NUMA awareness

COMSOL is aware of NUMA (Non-Uniform Memory Access) systems. NUMA systems can be systems with several CPU sockets or systems with CPUs based on multiple tiles. These systems are characterized by RAM memory modules that can be reached with different access times. COMSOL is automatically detecting the number of available sockets. Manual changes can be applied by specifying the Number of sockets in Preferences / Multicore and Cluster Computing. From the command line, the number of NUMA sets (sockets) can be set by means of the flag -numasets

See Also

See also Selecting hardware (solution 866).

Comsol Multiphysics Tutorial

See also Running COMSOL on clusters (solution 1001).

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