Added NaNReporter and HighMaReporter to LettuceCFD by MaxBille · Pull Request #248 · lettucecfd/lettuce

MaxBille · 2024-09-02T11:40:38Z

Description

Closes #174
Closes #272
Adding two reporters, that check for signs of simulation crashes (NaN in f or Ma > 0.3 in u) and abort simulation with respective abort messages, optional final vtk-frame and (in case of HighMaReporter) optional output file with locations of the 100 highest velocity magnitudes for crash-troubleshooting and analysis.

NaNReporter:

checks f in interval steps for any NaN value. If NaN is found, simulation is aborted.
if outdir is provided, lists indices q,x,y,[z] for all found NaN values (attention: produces large files for large intervals, because NaN replicates through the domain fast.
"old" argument (True, False) is for backwards compatibility with lettuce that has no aborting functionality in the simulation.py class. No vtk output in this case...
vtk argument (True, False) allows for vtk output of the current single flow state frame to outdir (if vtk_dir is not specified) or vtk_dir (if specified)

HighMaReporter:

calculates mach number from norm(u(f)) every interval steps and checks if Ma > 0.3 occurs. If Ma > 0.3 is found, simulation is aborted. The location (in LU coordinates) of up to 100 highest Ma numbers in the domain are reported to a file in outdir, if outdir argument is provided.
"old" argument (True, False) is for backwards compatibility with lettuce that has no aborting functionality in the simulation.py class. No vtk output in this case...
vtk argument (True, False) allows for vtk output of the current single flow state frame to outdir (if vtk_dir is not specified) or vtk_dir (if specified)
relies on unravel_index() method for torch.tensors, defined in the same file, for sorting and selection of high-Ma-locations.

DISCLAIMER: originally written for a modified version of lettuceCFD, based on Version 0.2.3; Adaptation for new Lettuce Master pending...

Checklist

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Add someone else as reviewer and wait for approval before merging.

pep8speaks · 2024-09-02T11:40:45Z

Hello @MaxBille! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

In the file tests/reporter/test_nan_reporter.py:

Line 7:29: E128 continuation line under-indented for visual indent
Line 14:80: E501 line too long (111 > 79 characters)

Comment last updated at 2024-09-05 09:53:25 UTC

shortened class definitions

adaptations of new reporter to native architecture, thx PhiSpel

pspelt is on fire... 🔥 👨‍💻

slightly more flexibility for step in which NaN fail occurs

…ation

….py.

PhiSpel

Could you check if we need to set non_native in BreakableSimulation? If so, can you rename to BreakableSimulationNonNative?
Maybe rename example to FailingTGVandObstacle.py?

- renamed FailingTGVandObstacle.py - removed hardcoded non-native execution from breakable simulation class. - set Obstacle flow to non-native

MaxBille · 2025-12-15T11:15:36Z

@PhiSpel would you mind, reviewing the changes I've made, regarding your change requests and recommendation? :) (if you have the time...)

lettuce/ext/_reporter/nan_repoter.py

lettuce/ext/_reporter/vtk_reporter.py

…ed super-class, cleaner output und functionaliy

…ation

PhiSpel

Some comments and changes still.
A nice setup!

Please remove lettuce/ext/_reporter/nan_repoter.py (the comments still apply to lettuce/ext/_reporter/failure_reporter.py!)

Generally, please revisit the typing of inputs and outputs of the classes and functions :)

examples/advanced_flows/FailingTGVandObstacle.py

lettuce/ext/_reporter/__init__.py

lettuce/ext/_reporter/failure_reporter.py

PhiSpel · 2025-12-17T19:57:43Z

lettuce/ext/_reporter/nan_repoter.py

+        self.failed_iteration = None
+        super().__init__(interval)
+
+    def __call__(self, simulation: 'Simulation'):


Since you import Simulation with no apparent issues, you can type it directly. Keep in mind, though: This must be a BreakableSimulation

@MaxBille have you tried this?

PhiSpel · 2025-12-17T20:00:34Z

lettuce/ext/_reporter/nan_repoter.py

+                    f'details!')
+                # telling simulation to abort simulation by setting i too high
+                simulation.flow.i = int(simulation.flow.i + 1e10)
+                # TODO: maybe make this more robust with a failed-flag in simulation and not rely on flow.i to be high/low?


Sure! Since we're working with BreakableSimulation anyway, it can just get a flag lastIteration, such that any other Reporter (also VTKReporter!) can also check if the simulation failed and output one last time. This is also implemented in NATriuM.

This may have been my own TODO-comment, btw ... :) So, for now, you could just post ths into another issue

@MaxBille is this a won't-do, or something for a new issue?

cleanup and small corrections to comments, typing and code formating

McBs · 2024-10-16T11:16:58Z

examples/advanced_flows/FailingTGVandObstacle.py

+    stencil=lt.D2Q9
+)
+nan_reporter = lt.NaNReporter(100, outdir="./data/nan_reporter", vtk=True)
+simulation = lt.BreakableSimulation(


Do the reporters only work with this specific Simulation class (i.e. BreakableSimulation)?
If not, I prefer to initialize this class within the example script (i.e. header).

Hi @MaxBille
Is there an update on this?

@McBs yes, it should be BreakableSimulation since we manipulate simulation.flow.i. If simulation this is not BreakableSimulation, it will continue running because call() contains a blind for-loop (

lettuce/lettuce/_simulation.py

Line 243 in d04e156

for _ in range(num_steps):

) that won't be broken.

PhiSpel

Typing is still incomplete

Added NaNReporter and HighMaReporter to LettuceCFD

8757a09

MaxBille requested review from McBs and PhiSpel September 2, 2024 11:41

MaxBille added the enhancement New feature or request label Sep 2, 2024

PhiSpel and others added 10 commits September 2, 2024 16:25

added example to test NaNReporter and HighMaReporter

f1c047d

shortened class definitions

pep8

b2e7048

Merge pull request #1 from PhiSpel/174-reporter-ps

4ec6378

adaptations of new reporter to native architecture, thx PhiSpel

added tests for highMa and NaN reporter

4ff09c0

tried reducing cognitive complexity for codeclimate

f48f76f

slightly updated nan-reporter examples

b0d4106

pep8 cosmetics

d92f9f6

Merge pull request #2 from PhiSpel/174-reporter-ps

7821519

pspelt is on fire... 🔥 👨‍💻

Update test_nan_reporter.py

b708a14

slightly more flexibility for step in which NaN fail occurs

Update test_nan_reporter.py

111ff99

MaxBille mentioned this pull request Aug 19, 2025

[Feature]: abort conditions - there are several reasons a simulation can fail #272

Open

MaxBille and others added 3 commits September 3, 2025 14:19

Merge branch 'lettucecfd:master' into 174-reporter-to-interrupt-simul…

3ccc698

…ation

minor comment

806cd26

moved class "Breakable Simulation" to _simulation.py from nan_repoter…

de3a78b

….py.

PhiSpel assigned PhiSpel and MaxBille Sep 4, 2025

PhiSpel requested changes Sep 4, 2025

View reviewed changes

renaming and native option:

11d56ca

- renamed FailingTGVandObstacle.py - removed hardcoded non-native execution from breakable simulation class. - set Obstacle flow to non-native

PhiSpel reviewed Dec 15, 2025

View reviewed changes

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MaxBille and others added 4 commits December 17, 2025 15:59

rewrite FailureReporter (NaN reporter and HighMa reporter) with unifi…

f0c7fa2

…ed super-class, cleaner output und functionaliy

Merge branch 'lettucecfd:master' into 174-reporter-to-interrupt-simul…

0a74e9c

…ation

corrected pytests for nan- and highma-reporter

c2da43d

corrected pytests for nan- and highma-reporter (2)

f06f0f8

MaxBille requested a review from PhiSpel December 17, 2025 15:34

MaxBille removed the request for review from McBs December 17, 2025 15:35

PhiSpel requested changes Dec 17, 2025

View reviewed changes

FailureReporter is now ABC class;

0c906c3

cleanup and small corrections to comments, typing and code formating

MaxBille requested a review from PhiSpel December 18, 2025 11:40

McBs approved these changes Dec 18, 2025

View reviewed changes

PhiSpel requested changes Dec 18, 2025

View reviewed changes

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Comment last updated at 2024-09-05 09:53:25 UTC

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MaxBille commented Sep 2, 2024 •

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