## All Solutions

### Computing Time and Space Integrals

Solution Number: 913 Versions: All versionsHow do I compute integrals over space or time? What if I want to use the result of these integrals elsewhere in my model? The COMSOL Multiphysics architecture allows you to evaluate integrals in both space and time in ...

### How does COMSOL Multiphysics handle complex-valued numbers and problems in the frequency domain?

Solution Number: 878 Applies to: AC/DC Module, Acoustics Module, COMSOL Multiphysics, MEMS Module, Plasma Module, RF Module, Semiconductor Module, Structural Mechanics Module, Wave Optics Module Versions: All versionsHow does COMSOL Multiphysics handle complex-valued numbers and problems in the frequency domain? Should I use the RMS, the peak, or the instantaneous value to specify sources in models being solved in the frequency ...

### What does degrees of freedom (DOFs) mean in COMSOL Multiphysics?

Solution Number: 875 Versions: All versionsWhat 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 ...

### Handling large models

Solution Number: 830 Versions: All versionsModels 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 ...

### Modeling of step transitions

Solution Number: 905 Versions: All versionsYou 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 ...

### Can COMSOL import topological data, meshes and images?

Solution Number: 838 Versions: All versionsCan COMSOL Multiphysics import meshes, topological data, and images? ##Importing Meshes Mimics and ScanIP can export volumetric meshes on COMSOL's own mesh format created from 3D scans, that can be directly imported ...

### Obtaining a HostID for licensing

Solution Number: 828 Versions: All versionsHow do I obtain a HostID for my license file? For many license types in the COMSOL product family, your COMSOL sales representative will ask you for some information in order to create installation codes. COMSOL uses ...

### Could not obtain license for COMSOL Multiphysics GUI

Solution Number: 903 Versions: All versionsAny of the following errors can appear for example if the COMSOL application has problems communicating with the license manager: License error: -15. Cannot connect to license server system. License error: -96. ...

### How do I solve a PDE with space derivatives of order higher than two?

Solution Number: 816 Versions: All versionsHow do I solve a PDE with space derivatives of order higher than two? For example, the equation for a function . Introduce names for the second derivatives of u, say . Then the equation can be written . ...

### What hardware do you recommend for COMSOL Multiphysics®?

Solution Number: 866 Versions: All versionsI am going to buy a new dedicated computer for running COMSOL Multiphysics®. What hardware do you recommend? Due to the wide range of different problem types that COMSOL Multiphysics® solves, the rapid pace of ...

## Learning Center Resources

Learn how to use the COMSOL Multiphysics^{®}software for modeling devices, designs, and processes. Access the Learning Center courses and articles below for modeling guidelines, step-by-step demonstrations, and exercise files.