MYSTRAN_Validation

Automated test suite for validation of Mystran.

Warning

It works but the design isn't stable yet and anything might change.

Run tests

py test.py path/to/mystran.exe

Build

Build f06magic somehow or use the included .exe file on Windows. If you're not using Windows, give the binary the .exe extension.

Features

Each test case is described by one line in the cases.txt file. There are two types - individual values and bulk comparison:

Individual values

Compares values from the f06 file to a reference value defined on the same line. This type of test is useful for comparing specific values in the solution to hand calcululations or published benchmark solutions.

Example line in cases.txt:

pth;    my test.dat;   SC/1/DISPLACEMENTS/GID/8/RX;            ;  1.234e-5;     2e-5%
        -----------    ---------------------------  ---------     --------      -----
       deck filename              path              operation    reference    tolerance
                                                                   value

This solves the file my test.dat then compares rotation about X at grid point 8 to 1.234e-5 with a tolerance that's reasonable for single precision or the 7 digits typical of values in an f06 file.

Path

Values are identified by hierarchical paths, which can lead to one or multiple values. Examples:

• SC/1/DISPLACEMENTS/GID/8/TY One value
• SC/1/SPCFORCES/GID/10-90/TX A range of 81 grid point IDs.
• SC/1/SOLIDSTRESSES/EID/4/CORNER/0/XY,YZ,ZX A list of three center stress components.
• SC/1/SOLIDSTRAINS/EID/1,5/CORNER/1-6/XX Both a list of 2 element IDs and a set of 6 corner numbers, giving 12 values.

Midsurface stress and strain

Use ZMID instead of Z1 or Z2 to calculate the average of the values at Z1 and Z2. This is useful for validating membrane strain when there's also bending. This average only equals the midsurface value if Z1 and Z2 were specified symmetrically in the PSHELL entry.

Reference value

The reference value can be either a number or a path that resolves to a single value.

Tolerance

If the tolerance ends with a %, it means percentage tolerance. This criterion is useful for most cases except where the reference value is zero. Percentage test passes if:

100 * |<test value> / <reference value> - 1| <= <tolerance>

If there's no % symbol in the tolerance field, it means difference tolerance. This criterion is useful where the reference value is zero. Difference test passes if:

|<test value> - <reference value>| <= <tolerance>

Operation

You can apply an operation before comparing to the reference value:

• None: Simply compare the value to the reference value. If there are multiple values, compare each one independently.
• SUM: Sum multiple values. Useful for validating reaction force balance over multiple nodes.
• DIFF: 1st value minus 2nd value.
• RATIO: 1st value divided by 2nd value.
• NORM: L2 norm. Useful for finding vector magnitude, ensuring that a lot of values are all zero, or ignoring the sign in an eigenvector.
• ANGLEFROMX: Angle of a translational DOF vector (TX, TY, TZ) from the X axis, ignoring the sign. The path you specify must not include the trailing /TX, /TY, or /TZ. If you specify multiple grid points, it sums them before calculating the angle. Useful for validating the direction of deflection of a mode shape.
• ANGLEFROMY: The same as ANGLEFROMX except from the Y axis.
• ANGLEFROMZ: The same as ANGLEFROMX except from the Z axis.
• ABSENT: Pass if the path doesn't exist. Useful for making sure a model that should fail didn't produce a solution.

Grid point transformations

Displacements and SPC forces can be transformed by matrices supplied in a separate file. The location and filename stem must be the same as the input deck's but with the extension .gptransform. This is useful for validating values in the basic coordinate system instead of different grid point coordinate systems used in the f06 file.

Shell angles

Shell stress, strain and engineering forces can be rotated by an angle about the z axis. Specify the rotation angle for the center and four corners in a separate file. The location and filename stem must be the same as the input deck's but with the extension .shellangles. This is useful for validating shell stress in the material or basic coordinate systems instead of the element coordinate system used in the f06 file.

Missing rows

Mystran sometimes omits rows with all zero values from the f06 file. These are treated as zero instead of errors at specific paths, such as /SC/*/SPCFORCES/GID/#/*.

Multiple test cases on the same deck

As an optimization, if a test case uses the same input deck as the previous test case, it will reuse the previous solution without running Mystran again.

Include files

INCLUDE <filename> on a line in the test case definition file includes the contents of the file at that point. Useful for organizing test cases or to temporarily disable groups of test cases you're not using.

Bulk comparison

Warning

Not working properly yet.

Compares most values in the solution's f06 file to a reference f06 file. This type of test is useful for discovering bugs -- when compared to MSC -- or detecting regressions -- when compared to an older Mystran solution.

Example line in cases.txt:

mys;    my_test.bdf;     -b=1   ;    0.0;    0.0

This solves my_test.bdf then compares displacements at all grid points to the reference f06 file reference_mystran/my_test.f06.

The reference f06 file is from either an earlier version of Mystran or MSC Nastran and you store it in either the /reference_mystran or /reference_msc directory respectively.

Values to compare can be filtered using arguments like -b=2 -s=1 -g=1,3,7

Uses F06magic to emulate F06csv.

The criteria and tolerances are not defined yet so don't use them.

Directory structure

• 📄 test.py - The main program
• 📄 cases.txt - Definitions of the test cases. Read by test.py.
• 📄 output.txt - Detailed output to help you debug test fails. Generated by test.py.
• 📁 decks - Input decks for the test cases. They can be organized into subdirectories.
• 📁 fails - .f06 files of failed tests to help you debug them. Generated by test.py.
• 📁 reference_msc - Reference .f06 solutions generated by MSC Nastran. Same filename stems and directory structure as the input decks.
• 📁 reference_mystran - Reference .f06 solutions generated by an earlier version Mystran. Same filename stems and directory structure as the input decks.
• 📁 working - Temporary working directory. Contains Mystran's output files, f06magic's script, etc.. Generated by test.py.