Sunday, June 29, 2025

Watch out for atan change in Visual Studio 2022 17.14.6

atan

 Recently we updated Visual Studio 2022 17.14.6 and the regression test reported errors. It turned out that atan implementation was changed resulting a different value for debug vs release builts with CPU's having AVX2. One can recreate this with the following values:

    const double ax          = 38.176459921094995;
    const double ay          = 15.964755390006060;
    const double dblRotation =  atan(ay/ax);

 We had to relax the equality checks; even for deterministic calculations.


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