# FEATool Multiphysics

- Frequently Asked Questions FAQ

## ⊕ General information

## ⊖ General information

### What is FEATool?

FEATool is short for Finite Element Analysis Toolbox, and is a fully integrated MATLAB computer simulation software suite for modeling and simulation of partial differential equations (PDE), continuum mechanics, physical processes, and engineering applications. |

### What kind of problems can FEATool solve?

FEATool can model and solve general systems of coupled partial differential equations (PDE) which enables simulation of many types of physical phenomena found in continuum mechanics, such as heat and mass transfer, computational fluid dynamics (CFD), structural mechanics (SME), computational electromagnetics (CEM), and chemical, transport, and reaction engineering problems. |

### What are the benefits of using FEATool?

FEATool Multiphysics is designed to be very easy to use and a fully integrated simulation package including CAD and geometry modeling tools, preprocessing and automatic grid generation, solvers, and post processing. This makes it possible to very quickly set up simulation experiments and test ideas, all in the same program so that the time to (start) solution is very short. Moreover, since FEATool integrates seamlessly with MATLAB and FEniCS one can also leverage the m-scripting and Python languages and functions together with FEATool. |

### What is the design philosophy behind FEATool?

FEATool is specifically designed to be easy to use, and also very general so that any kind of equation or problem can be studied. Moreover, FEATool interfaces naturally with MATLAB, and is extensible so as to interface with other software and simulation tools such as OpenFOAM, FEniCS, Gmsh, Triangle, and Plotly. |

### What programming language is FEATool written in?

FEATool is written in the MATLAB m-code script language, and is therefore also extensible so users can call their own preprocessing, solvers, postprocessing routines through hooks and function overloading. |

### What limitations does FEATool have?

Since m-code is not pre-compiled but Just-In-Time (JIT) interpreted by MATLAB it will in general not be as fast or memory efficient as an equivalent code written in C or Fortran. However, library calls, for example calls to linear solvers such as Suitesparese/UMFPACK, are just as efficient as other software using these same libraries. Moreover, core FEM library functions of FEATool have been vectorized, optimized, and benchmarked to run as fast as Fortran. |

### Is there more documentation/tutorials available?

FEATool comes with a full documentation suite including Quickstart, User’s, Modeling and Tutorial guides. Also keep and eye out on the FEATool Blog which frequently features tutorials, tips, and examples, and subscribe to the FEATool Newsletter which features information about new releases and important updates. |

### I have used FEATool in my research, article, or paper, how should I attribute FEATool?

Please add a reference to the FEATool User’s Guide and homepage, for example: |

### I think I have found a bug in FEATool, what should I do?

Please use the |

## ⊕ System requirements

## ⊖ System requirements

### What is required to run FEATool?

FEATool requires either MATLAB Version 7.9 (R2009b) or later, furthermore, a 64-bit system with 4 GB or more RAM memory is recommended. |

### What operating systems does FEATool support?

FEATool can run on any computer system that supports MATLAB, such as Windows, Linux, Unix, and Mac OSX. |

## ⊕ Installation

## ⊖ Installation

### How do I install FEATool?

To install FEATool follow the installation instructions in the Quickstart guide. |

### How do I get started with FEATool?

Start by working through one of the tutorial examples found in the FEATool Quickstart Guide or start any of the tutorials found in the |

### How do I install the FEniCS FEM solver?

Please follow the installation instructions on the FEniCS project website, noting that FEniCS must be callable through Python with the command |

### How do I install the Gmsh mesh generator?

FEATool will automatically try to download and install Gmsh if requested. If this fails, manually download the executable binaries for your system from the Gmsh website. Then extract and copy the Gmsh binary ( |

### How do I install the OpenFOAM CFD solver?

For Windows systems it is recommended to install and use the pre-compiled blueCFD-core (2017) binaries from blueCAPE. For Ubuntu Linux OpenFOAM can be installed with the For other systems, please follow the installation recommendations from the official OpenFOAM website. For the OpenFOAM solver integration to work FEATool requires that the simpleFoam and pimpleFoam solver binaries are directly callable from Linux bash and/or Windows bat shell files. |

### How do I install the Triangle mesh generator?

FEATool will automatically try to download and install Triangle if requested. If this fails, manually download the source code from the Triangle website. Then extract the source file |

## ⊕ Multiphysics

## ⊖ Multiphysics

### Can FEATool simulate coupled multiphysics problems?

FEATool technically supports any number of coupled equations and physics modes. (Limited by system constraints, as increasing the number of coupled equations will require more memory and time to solve.) |

### Can FEATool solve 3D problems?

FEATool supports 1D, 2D, Axisymmetric (Cylindrical coordinates 2.5D), and problems in full 3D. |

### What kind of physics can be simulated?

There are currently 15 pre-defined physics application modes available |

### How do I couple physics modes (implement a multiphysics model)?

Add additional equations can be added with the |

## ⊕ Finite element method

## ⊖ Finite element method

### What algorithm or method does FEATool use to solve problems?

FEATool uses the finite element method (FEM) to discretize and solve the underlying partial differential equations (PDEs). Moreover, time dependent problems are discretized and solved with the backward Euler, Crank-Nicolson, and Fractional-Step-Theta time stepping schemes. |

### What FEM shape/basis functions are supported?

FEATool supports standard 1st through 5th order conforming Lagrange (P |

### Can I access finite element matrices and/or bi-linear forms?

For a predefined |

### How do I access the finite element problem data?

The finite element problem is defined in a struct variable called |

### How do I enter my own equations?

Press the |

### Does FEATool support parallel solvers?

MATLAB does not per default include parallel sparse linear solvers. However, one can export FEATool models to FEniCS project Python scripts with support for parallel solvers, and run CFD models in parallel with OpenFOAM. Alternatively, it is also possible to run MATLAB instances in parallel batches. |

### What dimensions/units does FEATool use?

FEATool does not use any fixed unit system, it is therefore up to the user define and use consistent units. If for example the geometry length unit is chosen as meters [m], then standard SI-units are recommended for the equation coefficients. Using another length unit such as millimeters [mm] or inches, would require rescaling of the equation coefficients to preserve consistency. |

## ⊕ Import and export

## ⊖ Import and export

### How do I import and export grids/data?

Import and exporting grids and data from various formats can be done using the corresponding options from the |

### How do I export solution data?

First export the FEA problem struct from the GUI to the main MATLAB workspace by selecting |

### How do I evaluate and export general expressions?

Expressions in points and lines can be evaluated using the c_data = { 'x', 'y', 'u', 'ux', '2*sin(u*x)^2' };The data can now be saved and exported to a file with the MATLAB `save` command (for example `save('-ascii','mydata.txt','data')` ). |

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