Contents

• NAME
• SYNOPSIS
  • F95 INTERFACE
  • C INTERFACE
• ARGUMENTS

NAME

     cost - compute the discrete Fourier cosine transform  of  an
     even   sequence.    The  COST  transforms  are  unnormalized
     inverses of themselves,  so  a  call  of  COST  followed  by
     another call of COST will multiply the input sequence by 2 *
     (N-1).

SYNOPSIS

     SUBROUTINE COST(N, X, WSAVE)

     INTEGER N
     REAL X(*), WSAVE(*)

     SUBROUTINE COST_64(N, X, WSAVE)

     INTEGER*8 N
     REAL X(*), WSAVE(*)

  F95 INTERFACE
     SUBROUTINE COST(N, X, WSAVE)

     INTEGER :: N
     REAL, DIMENSION(:) :: X, WSAVE

     SUBROUTINE COST_64(N, X, WSAVE)

     INTEGER(8) :: N
     REAL, DIMENSION(:) :: X, WSAVE

  C INTERFACE
     #include <sunperf.h>

     void cost(int n, float *x, float *wsave);

     void cost_64(long n, float *x, float *wsave);

ARGUMENTS

     N (input) Length of the sequence to be  transformed.   These
               subroutines  are  most  efficient  when N - 1 is a
               product of small primes.  N >= 2.

     X (input/output)
               On entry, an array  of  length  N  containing  the
               sequence  to  be transformed.  On exit, the cosine
               transform of the input.
     WSAVE (input)
               On entry, an array with dimension of at least   (3
               * N + 15), initialized by COSTI.