Support Knowledge Base

Solver

1096: COMSOL and Multithreading

This solution describes how COMSOL takes advantage of multicore computers. COMSOL supports two mutual modes of parallel operation: shared-memory parallelism and distributed-memory parallelism (cluster support)....
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1062: BDF, Generalized Alpha, and Runge-Kutta Methods

What numerical methods are available when using a Time-Dependent Solver? What are their relative benefits and when should I use them? The Time-Dependent Solver offers three different time stepping methods: The...
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1030: Error: "Out of memory"

I get an error message, that contains the words Out of memory, for example: Out of memory during LU factorization. or Out of memory during assembly Background Before resolving this issue, you should go through...
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1001: Running COMSOL® in parallel on clusters

This solution describes how you enable distributed parallelization (cluster jobs) in COMSOL Multiphysics®. COMSOL supports two mutual modes of parallel operation: shared-memory parallel operations and...
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973: My flux calculation seems wrong

I am solving a diffusion-like problem in COMSOL Multiphysics and discovered that boundaries that are defined with insulation/symmetry conditions have an integrated value of the normal component of the flux that is far...
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964: Error: Failed to find a solution. Returned solution is not converged

I get this message: Failed to find a solution. The relative residual (0.28) is greater than the relative tolerance. Returned solution is not converged. Messages similar to this are returned for nonlinear problems...
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952: Avoiding negative concentrations

Why do I get negative values of the concentration in my diffusion, convection and reaction model? Why do I see values that go below, or above, their lowest, or highest, possible values based upon the boundary...
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905: Modeling of step transitions

You may want to define loads, material properties, or boundary conditions that vary abruptly with respect to the solution, or with respect to time. This can, however, lead to a solution which is discontinuous in space...
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875: What does degrees of freedom (DOFs) mean in COMSOL Multiphysics?

What does degrees of freedom (DOFs) mean in COMSOL Multiphysics? The solution time and memory requirements are strongly related to the number of degrees of freedom in the model. It is often desirable to be able to...
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830: Handling large models

Models with many domains, boundaries, and physics features are slow to work with. Large models can contain hundreds or even thousands of domains, boundaries, and physics features. Such a large number of features...
Version: All versions - Platform: All Platforms