IronLanguages / IronLanguages/ironpython3
math.cos/math.tan precision near pi/2 does not match CPython on .NET Framework
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Description
Specifically, the test tan0064 (from cmath_testcases.txt in 3.6 which is run by test_math) is failing. It checks the value of math.tan(1.5707963267948961) and expects it be be 1978937966095219.0, but .NET Framework is giving me 1978945885716843.0.
Similarly, math.cos(1.5707963267948961) does not return the expected 5.053215498074303e-16 but instead gives 5.0531952754118148e-16.
I don't think this is worth addressing since .NET Core produces the same values as CPython and so I will skip the failing case on .NET Framework.
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Research direction
The failing case is tan0064 from cmath_testcases.txt in 3.6 and is run by test_math. Start there and compare the .NET Framework results with the stated CPython and .NET Core values. The issue proposes skipping this platform-specific case rather than changing the math implementation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- csharp, python
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 20/100