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"values can't be empty (Parameter 'values')" in LowlandModalityDetector

See original GitHub issue

To reproduce the issue, please use this list of values inside MultimodalityDetectionDemo.cs instead of the synthetic one generated in multiple steps by AddRange:

            var data = new List<double>(new double[] {
              171, 159, 150, 160, 160, 150, 151, 150, 160, 150, 160, 156, 144, 170, 150, 150, 160, 150, 150, 160, 150, 150, 160, 
              149, 161, 150, 150, 160, 150, 160, 150, 160, 150, 150, 160, 150, 160, 160, 154, 147, 160, 150, 160, 150, 160, 150, 
              150, 160, 150, 160, 151, 160, 150, 150, 160, 150, 160, 157, 153, 150, 160, 150, 160, 150, 150, 161, 160, 150, 160, 
              150, 150, 160, 150, 150, 160, 150, 160, 150, 160, 161, 149, 161, 160, 160, 160, 160, 157, 153, 151, 160, 150, 160, 
              150, 150, 150, 160, 150, 150, 160, 159, 151, 150, 160, 151, 160, 150, 160, 150, 150, 160, 160, 150, 160, 150, 161, 
              150, 150, 160, 160, 158, 152, 150, 160, 150, 160, 160, 163, 147, 160, 151, 160, 160, 180, 160, 159, 151, 160, 150, 
              150, 160, 153, 157, 150, 160, 171, 170, 150, 160, 160, 150, 160, 150, 161, 160, 150, 150, 160, 160, 150, 150, 160, 
              150, 150, 170, 160, 150, 160, 160, 151, 160, 162, 180, 166, 159, 171, 150, 160, 190, 161, 170, 170, 160, 166, 155, 
              170, 150, 160, 150, 150, 168, 162, 160, 160, 150, 165, 155, 161, 150, 160, 160, 160, 159, 171, 160, 160, 181, 160, 
              166, 154, 160, 191, 169, 160, 160, 150, 160, 203, 161, 159, 150, 160, 150, 160, 160, 165, 166, 160, 150, 160, 164, 
              156, 150, 160, 150, 160, 150, 160, 150, 161, 149, 161, 150, 150, 160, 160, 150, 160, 150, 161, 160, 170, 170, 160, 
              160, 160, 183, 172, 172, 164, 155, 161, 160, 160, 168, 152, 150, 160, 160, 160, 160, 159, 161, 160, 173, 147, 160, 
              160, 151, 170, 150, 163, 166, 146, 161, 170, 281, 164, 147, 160, 160, 150, 153, 167, 174, 152, 174, 153, 150, 150, 
              160, 160, 150, 160, 160, 158, 152, 161, 160, 150, 160, 151, 162, 147, 159, 161, 150, 150, 160, 151, 150, 176, 164, 
              160, 160, 160, 160, 160, 160, 160, 170, 171, 172, 202, 180, 183, 182, 189, 175, 166, 161, 163, 152, 172, 159, 160, 
              161, 161, 170, 165, 170, 165, 150, 163, 160, 160, 162, 161, 150, 160, 160, 170, 160, 160, 160, 161, 160, 160, 160, 
              180, 170, 161, 167, 152, 161, 150, 160, 160, 160, 160, 160, 170, 166, 155, 150, 160, 180, 155, 160, 159, 161, 160, 
              170, 160, 160, 150, 160, 161, 150, 160, 170, 160, 160, 160, 150, 160, 160, 150, 171, 161, 149, 163, 147, 160, 150, 
              160, 160, 160, 165, 145, 158, 153, 150, 160, 150, 160, 159, 151, 160, 150, 150, 150, 161, 150, 160, 150, 150, 165, 
              146, 160, 150, 150, 159, 151, 160, 160, 150, 160, 180, 150, 160, 167, 163, 247, 160, 170, 159, 151, 160, 170, 160, 
              171, 160, 159, 168, 153, 190, 170, 150, 170, 160, 170, 151, 182, 148, 160, 160, 150, 170, 150, 150, 160, 155, 155, 
              152, 160, 163, 147, 150, 160, 152, 155, 156, 152, 150, 157, 155, 150, 150, 160, 160, 150, 150, 161, 149, 159, 161, 
              160, 173, 167, 150, 150, 150, 150, 150, 160, 150, 151, 170, 157, 154, 160, 160, 150, 163, 158, 160, 150, 150, 160, 
              145, 170, 161, 156, 154, 150, 150, 160, 150, 160, 150, 150, 160, 160, 161, 171, 174, 160, 150, 160, 160, 180, 150, 
              160, 171, 150, 160, 160, 160, 171, 170, 140, 161, 160, 160, 160, 149, 166, 147, 160, 160, 161, 150, 150, 159, 161, 
              160, 170, 158, 155, 170, 160, 160, 180, 151, 160, 170, 170, 160, 150, 160, 150, 170, 160, 177, 160, 150, 181, 180, 
              170, 159, 161, 160, 160, 160, 160, 151, 169, 158, 163, 160, 160, 170, 160, 160, 160, 150, 160, 160, 160, 160, 150, 
              160, 165, 155, 161, 170, 160, 160, 150, 160, 160, 151, 170, 160, 150, 160, 160, 149, 171, 160, 160, 150, 160, 150, 
              160, 160, 160, 150, 161, 150, 160, 150, 150, 150, 160, 160, 150, 150, 160, 160, 150, 160, 151, 150, 163, 146, 156, 
              144, 159, 151, 160, 162, 148, 150, 160, 150, 160, 161, 150, 165, 155, 160, 160, 170, 150, 160, 150, 160, 151, 164, 
              146, 160, 160, 160, 160, 161, 160, 162, 159, 151, 163, 157, 160, 150, 170, 169, 161, 160, 151, 160, 170, 160, 150, 
              150, 160, 150, 150, 150, 150, 160, 151, 159, 151, 181, 163, 150, 149, 160, 150, 150, 160, 159, 151, 151, 160, 160, 
              160, 176, 160, 154, 150, 160, 160, 161, 166, 181, 173, 161, 160, 157, 157, 157, 152, 170, 151, 170, 170, 170, 160, 
              160, 170, 160, 169, 162, 160, 165, 165, 158, 155, 157, 160, 170, 175, 165, 165, 155, 181, 161, 149, 170, 160, 170, 
              160, 160, 160, 160, 161, 150, 160, 158, 280, 191, 160, 175, 648, 164, 164, 157, 155, 161, 159, 156, 156, 159, 165, 
              166, 163, 156, 156, 151, 164, 160, 160, 150, 160, 150, 160, 159, 151, 161, 160, 170, 160, 160, 160, 160, 160, 157, 
              159, 160, 161, 165, 159, 152, 151, 159, 160, 160, 151, 160, 165, 172, 149, 160, 160, 160, 160, 160, 161, 160, 170, 
              161, 167, 166, 157, 160, 160, 160, 164, 156, 181, 165, 155, 160, 160, 160, 169, 152, 186, 165, 160, 164, 159, 170, 
              171, 175, 155, 160, 160, 160, 158, 152, 160, 150, 160, 160, 161, 160, 150, 160, 160, 150, 160, 150, 163, 147, 190, 
              180, 162, 149, 160, 150, 170, 150, 177, 153, 160, 159, 151, 160, 163, 148, 160, 160, 160, 160, 160, 159, 162, 159, 
              161, 164, 156, 150, 165, 154, 150, 161, 160, 152, 158, 162, 148, 160, 160, 150, 186, 149, 160, 160, 160, 150, 164, 
              160, 161, 159, 168, 161, 166, 160, 150, 160, 166, 155, 150, 160, 150, 150, 160, 161, 159, 158, 152, 150, 160, 150, 
              160, 161, 150, 160, 160, 160, 150, 160, 150, 160, 160, 160, 160, 174, 152, 160, 156, 154, 150, 161, 160, 171, 154, 
              159, 161, 156, 166, 154, 150, 160, 160, 170, 150, 160 
});

If you execute the mode detection the program crashes at:

System.ArgumentOutOfRangeException
  HResult=0x80131502
  Message=values can't be empty (Parameter 'values')
  Source=Perfolizer
  StackTrace:
   at Perfolizer.Common.Assertion.NotNullOrEmpty[T](String name, IReadOnlyList`1 values) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Common\Assertion.cs:line 24
   at Perfolizer.Common.Sample..ctor(IReadOnlyList`1 values) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Common\Sample.cs:line 29
   at Perfolizer.Mathematics.Multimodality.LowlandModalityDetector.<DetectModes>g__LocalMode|5_3(Double location, Double left, Double right, <>c__DisplayClass5_0& ) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Mathematics\Multimodality\LowlandModalityDetector.cs:line 70
   at Perfolizer.Mathematics.Multimodality.LowlandModalityDetector.DetectModes(Sample sample, IDensityHistogramBuilder densityHistogramBuilder, Boolean diagnostics) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Mathematics\Multimodality\LowlandModalityDetector.cs:line 162
   at Perfolizer.Mathematics.Multimodality.LowlandModalityDetector.DetectModes(Sample sample) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Mathematics\Multimodality\LowlandModalityDetector.cs:line 27
   at Perfolizer.Mathematics.Multimodality.ModalityDetectorExtensions.DetectModes(IModalityDetector modalityDetector, IReadOnlyList`1 values) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer\Mathematics\Multimodality\ModalityDetectorExtensions.cs:line 16
   at Perfolizer.Demo.MultimodalityDetectionDemo.Run() in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer.Demo\MultimodalityDetectionDemo.cs:line 65
   at Perfolizer.Demo.Program.<>c.<.cctor>b__3_9() in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer.Demo\Program.cs:line 19
   at Perfolizer.Demo.Program.Main(String[] args) in C:\Users\stf\Source\Repos\perfolizer\src\Perfolizer\Perfolizer.Demo\Program.cs:line 47

At the site of the crash LocalMode is called with location = 160, left = 160.00000000000006 and right = 160. Because left > right modeValues is left empty.

The data is real performance data collected with a very granular clock. This is using commit 435a14d6a2ab3059d639ea30cb0170ec0ab22fa7 from 9 days ago (the latest as of today).

Cheers.

Issue Analytics

State:
Created 2 years ago
Comments:5 (3 by maintainers)

Top GitHub Comments

1reaction

lstefano71commented, May 24, 2021

Thank you very much! I’ve been following your blog since I’ve discovered Perfolizer. I did not change my impression: impressive content and very good exposition. I am really happy you are sharing your knowledge with the rest of the world.

1reaction

AndreyAkinshincommented, Apr 7, 2021

@lstefano71, thanks for the bug report. Your case exposed a serious problem. When I designed LowlandModalityDetector, I was so focused on continuous distributions that I forgot to consider discrete distributions. Currently, this case is not fully supported. Specifically, if we have a bunch of identical elements in the data, we might get equal values of different quantiles. This prevents us from building a smooth probability density function.

Fortunately, I have a few ideas on how to fix it. Once we detect a “discrete-like” distribution, we could switch to another density estimation approach. I guess we could try classic histograms with a few adjustments. I need some time for experiments, but I hope to support such cases in the nearest future.