vrda_sincos: Array double precision Sine and Cosine

• C Prototype:
  • void vrda_sincos (int n, double *x, double *ys, double *yc)

  • Inputs:

    • int	n	- the number of values in both the input and output arrays.
      double	*x	- pointer to the array of input values.
      double	*ys	- pointer to the array of sin output values.
      double	*yc	- pointer to the array of cos output values.

  • Outputs:
    • Sine for each x value, filled into the ys array.
    • Cosine for each x value, filled into the yc array.
• Fortran Subroutine Interface:
  • SUBROUTINE VRDA_SINCOS(N,X,YS,YC)
  • Inputs:
    • INTEGER N - the number of values in both the input and output arrays.
    • DOUBLE PRECISION X(N) - array of double precision input values.
  • Outputs:
    • DOUBLE PRECISION YS(N) - array of Sines of input values.
    • DOUBLE PRECISION YC(N) - array of Cosines of input values.
• Notes:
  • vrda_sincos computes the Sine and Cosine functions for each element of an array of input arguments.
    This routine accepts an array of double precision input values, computes sincos(x) for each input value, and stores the results in the arrays pointed to by the ys and yc pointer inputs. It is the responsibility of the calling program to allocate/deallocate enough storage for the output array. This is a relaxed version of sincos, suitable for use with fastmath compiler flags or applications not requiring full error handling. Denormal inputs may produce unpredictable results. Special case inputs produce C99 return values. The routine is accurate to better than 2 ulp over the valid input range.
• Special case return values:

  • Input	Output
    QNaN	same QNaN
    SNaN	same NaN converted to QNaN
    +infinity	QNaN
    -infinity	QNaN

• Performance:
  • 180 cycles for most valid inputs < 5e5 (43 cycles per Sin and Cos of a value), n = 24.