This math is driving me crazy!

DKDiveDude (1)
Why do the two below give different results? I need the second result to be the same as the first.

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  float mySampleRate = 44100.0f;

  int phase = 4294967296.0f / mySampleRate * 1046.5f; // Phase is 101920256

  float cycle = 1046.5f;
  int phase = 4294967296.0f / mySampleRate * cycle; // Phase is 101920480


Windows 10, VS 2019
Last edited on
deleted account xyzzy (5768)
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#include <iostream>

int main()
{
   float mySampleRate = 44100.0f;

   int phase = 4294967296.0f / mySampleRate * 1046.5f; // Phase is 101920256

   std::cout << phase << '\n';

   float cycle = 1046.5f;

   phase = 4294967296.0f / mySampleRate * cycle; // Phase is 101920480

   std::cout << phase << '\n';
}

101920256
101920256

Change the floats to doubles and the output is:
101920255
101920255


Win10 Pro x64 and VS 2019 Community.
deleted account xyzzy (5768)
Code::Blocks gives the same results, floats or doubles. Some part of your code you didn't post is probably changing the value you are expecting.
Last edited on
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