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NAME
     dsinqb - synthesize a Fourier sequence from its  representa-
     tion  in  terms of a sine series with odd wave numbers.  The
     xSINQ operations are unnormalized inverses of themselves, so
     a  call to xSINQF followed by a call to xSINQB will multiply
     the input sequence by 4 * N.  The VxSINQ operations are nor-
     malized,  so a call of VxSINQF followed by a call of VxSINQB
     will return the original sequence.

SYNOPSIS
     SUBROUTINE SINQB (N, RX, RWSAVE)

     SUBROUTINE DSINQB (N, DX, DWSAVE)

     SUBROUTINE VSINQB (M, N, RX, RXT, MDIMX, RWSAVE)

     SUBROUTINE VDSINQB (M, N, DX, DXT, MDIMX, DWSAVE)



     #include <sunperf.h>

     void sinqb (int n, float *sx, float *wsave) ;

     void dsinqb (int n, double *dx, double *wsave) ;

     void vsinqb(int m,  int  n,  float  *sx,  int  mdimx,  float
               *wsave) ;

     void vdsinqb(int m, int n, double  *dx,  int  mdimx,  double
               *wsave) ;

ARGUMENTS
     M         (For vector operations only.)
               The number of sequences to be transformed.   M  >=
               0.

     N         Length of the sequence to be  transformed.   These
               subroutines are most efficient when N is a product
               of small primes.  N >= 0.

     xX        On entry, an array  of  length  N  containing  the
               sequence  to  be transformed.  For VxSINQB, a real
               two- dimensional array with dimensions of (MDIMX x
               N)   whose   rows  contain  the  sequences  to  be
               transformed.  On exit, the quarter-wave sine  syn-
               thesis of the input.

     xXT       (For vector operations only.)
               A real two-dimensional work array with  dimensions
               of (MDIMX x N).

     MDIMX     (For vector operations only.)
               Leading dimension of the  arrays  xX  and  xXT  as
               specified in a dimension or type statement.  MDIMX
               >= M.

     xWSAVE    On entry, an array with dimension of at least   (3
               *  N  + 15) for scalar subroutines or (2 * N + 15)
               for vector subroutines, initialized by  xSINQI  or
               VxSINQI.

SAMPLE PROGRAM
           PROGRAM TEST
           IMPLICIT NONE
     C
           INTEGER         M, N
           PARAMETER      (M = 1)
           PARAMETER      (N = 6)
     C
           INTEGER         I
           REAL            PI, WSAVE(N + 15), X(M, N), XT(M, N)
     C
           EXTERNAL        VSINQB, VSINQF, VSINQI
           INTRINSIC       ACOS, SIN
     C
     C     Initialize the first row of the array to a real odd
     C     quarter-wave sequence, that is, it can be expanded in
     C     terms of a cosine series with only odd wave numbers.
     C
           PI = ACOS (-1.0)
           DO 100, I=1, N
             X(M,I) = 40.0 * SIN ((I * PI / (2.0 * N)))
       100 CONTINUE
     C
           CALL VSINQI (N, WSAVE)
           PRINT 1000
           PRINT 1010, (X(M, I), I = 1, N)
           CALL VSINQF (M, N, X, XT, M, WSAVE)
           PRINT 1020
           PRINT 1010, (X(M, I), I = 1, N)
           CALL VSINQB (M, N, X, XT, M, WSAVE)
           PRINT 1030
           PRINT 1010, (X(M, 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:
       49.0   0.0   0.0   0.0   0.0   0.0
      Recovered Sequence:
       10.4  20.0  28.3  34.6  38.6  40.0

Партнёры:

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