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MFiX 18.1 Release Announcement

Dear MFiX user,

We are pleased to announce the MFiX 18.1 release. Please download the latest version. See the release note below that highlights the changes from the previous version.

Please send any software related questions to or administrative questions to


The MFiX Development Team

MFiX 18.1 Release note:

  • New features:
    • Monitors: Ability to setup monitor region(s) to plot Quantities of Interest (QoI) vs. time. Simple operators (min, max, arithmetic average) or advanced operators (surface, volume integrals, etc.) can be applied to variables to create the QoI.
    • Installation:
      • Conda environment files are now provided for easier installation
      • Conda environment files specify the same conda package versions tested by the MFiX development team
      • Conda environment files help upgrading MFiX or installing multiple MFiX versions on the same system
      • VTK 8 is now available in the main Anaconda distribution
    • Custom solver build:
      • The compiler can now be specified in the Build Dialog when building fro the GUI
      • Alternative interactive solver implementation with Crow C++ framework is now available
  • Improvements:
    • Wider range of Parameters usage: Parameters can now be used in any text input
    • Better management of sub-directories
    • Custom labels for reaction rates arrays saved in VTU files
    • Dynamic allocation of cut cell arrays
    • RUN_NAME is now independent of the .mfx file name
    • CPU and RAM usage displayed in the GUI
    • Filter NaNs out from line plots
    • Scalable icons, better look on high DPI displays
    • Display wall-time at each time step for both fluid and DEM loops
    • Internal navigation through the GUI allows to view all settings while in running/paused state
  • Notable bug fixes:
    • Removed unnecessary constraints for chemical reactions definition
    • Fixed initialization bug in DEM with Variable Solids Density
    • Fixed code hanging when singular matrix is detected in BICGS linear equation solver
    • Fixed a bug in the DEM tangential force calculation
    • Fixed wrong units for heat of formation displayed in GUI
    • Duplicate triangles making up walls along the domain extent during DEM heat transfer calculation are now excluded
    • Flush or terminate error manager message during data check
  • Known issues:
    • Recommended Fortran compilers to build the custom solver: GNU versions 4.6 to 6.3
    • Do not use aggressive optimization (-O2 or -O3) with GNU compiler versions 7.2 and above
    • With the new vtk 8.1.0, Boolean operations on primitive shapes may fail when loading old .mfx files. This can usually be remedied by increasing the primitive shape resolution.

Please see the online documentation for additional information.