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NAME
     vsinqi - initialize the array xWSAVE, which is used in  both
     xSINQF and xSINQB.

SYNOPSIS
     SUBROUTINE SINQI (N, RWSAVE)

     SUBROUTINE DSINQI (N, DWSAVE)

     SUBROUTINE VSINQI (N, RWSAVE)

     SUBROUTINE VDSINQI (N, DWSAVE)



     #include <sunperf.h>

     void sinqi (int n, float *rwsave) ;

     void dsinqi (int n, double *dwsave) ;

     void vsinqi (int n, float *rwsave) ;

     void vdsinqi (int n, float *dwsave) ;

ARGUMENTS
     N         Length of the sequence  to  be  transformed.   The
               method  is  most  efficient when N is a product of
               small primes.

     xWSAVE    On entry, an array with a dimension of at least (3
               *  N  + 15) for scalar subroutines or (2 * N + 15)
               for vector subroutines.  The same work  array  can
               be  used  for  both xSINQF and xSINQB as long as N
               remains unchanged.  Different  xWSAVE  arrays  are
               required for different values of N.  This initial-
               ization does not have to be repeated between calls
               to xCSINF or xCSINB as long as N and xWSAVE remain
               unchanged,  thus  subsequent  transforms  can   be
               obtained faster than the first.

SAMPLE PROGRAM
           PROGRAM TEST
           IMPLICIT NONE
     C
           INTEGER            N
           PARAMETER         (N = 6)
     C
           INTEGER            I
           REAL               PI, WSAVE(3 * N + 15), X(N)
     C
           EXTERNAL           SINQB, SINQF, SINQI
           INTRINSIC          ACOS, SIN
     C
     C     Initialize array X to a real odd quarter-wave sequence,
     C     that is,it can be expanded in terms of a sine series with
     C     only odd wave number.
     C
           PI = ACOS (-1.0)
           DO 100, I=1, N
             X(I) = 40.0 * SIN (I * PI / (2.0 * N))
       100 CONTINUE
     C
           PRINT 1000
           PRINT 1010, (X(I), I = 1, N)
           CALL SINQI (N, WSAVE)
           CALL SINQF (N, X, WSAVE)
           PRINT 1020
           PRINT 1010, (X(I), I = 1, N)
           CALL SINQB(N, X, WSAVE)
           PRINT 1030
           PRINT 1010, (X(I), I = 1, N)
     C
      1000 FORMAT (1X, 'Original Sequence: ')
      1010 FORMAT (1X, 100(F5.1, 1X))
      1020 FORMAT (1X, 'Transformed Sequence: ')
      1030 FORMAT (1X, 'Recovered Sequence: ')
     C
           END

SAMPLE OUTPUT
      Original Sequence:
       10.4  20.0  28.3  34.6  38.6  40.0
      Transformed Sequence:
      240.0   0.0   0.0   0.0   0.0   0.0
      Recovered Sequence:
      248.5 480.0 678.8 831.4 927.3 960.0

Партнёры:

Хостинг: