CUDA sincospi function precision

Question

I was looking all over and I couldn\'t find how the function computes or uses it\'s PI part. For my project I am using a defined constant that has precision of 34 decimal pl

Answer 1

The maximum ulp error for sincospi() is the same as the maximum ulp error for sincos(): The results differ by up to 1 ulp from a correctly rounded reference, or stated differently, the results deviate by less than 1.5 ulps from the infinitely precise mathematical result. On average, more than 90+% of results are correctly rounded. The maximum observed error for all CUDA math functions is documented in an appendix of the CUDA C Programming Guide. The accuracy of sincospi(x) is superior to the accuracy achieved by sincos(M_PI*x), as the latter incurs additional rounding error due to the multiplication of the function argument.