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Интерактивная система просмотра системных руководств (man-ов)

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vdcost (3)
  • >> vdcost (3) ( Solaris man: Библиотечные вызовы )
  • 
    NAME
         vdcost - compute the discrete Fourier cosine transform of an
         even   sequence.   The  xCOST  transforms  are  unnormalized
         inverses of themselves, so  a  call  of  xCOST  followed  by
         another  call of xCOST will multiply the input sequence by 2
         * (N-1).  The VxCOST transforms are normalized, so a call of
         VxCOST followed by a call of VxCOST will return the original
         sequence.
    
    SYNOPSIS
         SUBROUTINE COST (N, RX, RWSAVE)
    
         SUBROUTINE DCOST (N, DX, DWSAVE)
    
         SUBROUTINE VCOST (M,N, RX, RXT, MDIMX, RWSAVE)
    
         SUBROUTINE VDCOST (M,N, DX, DXT, MDIMX, DWSAVE)
    
    
    
         #include <sunperf.h>
    
         void cost (int n, float *sx, float *wsave) ;
    
         void dcost (int n, double *dx, double *wsave) ;
    
         void vcost(int m, int n, float *sx, int mdimx, float *wsave)
                   ;
    
         void vdcost(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 - 1 is a
                   product of small primes.  N >= 2.
    
         xX        On entry, an array  of  length  N  containing  the
                   sequence  to  be  transformed.  For VxCOST, a real
                   two- dimensional array with dimensions of (MDIMX x
                   (N+1))  whose  rows  contain  the  sequences to be
                   transformed.  On exit, the cosine transform of the
                   input.
    
         xXT       (For vector operations only.)
                   A real two-dimensional work array with  dimensions
                   of (MDIMX x (N-1)).
    
         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), initialized by xCOSTI
                   or VxCOSTI.
    
    SAMPLE PROGRAM
               PROGRAM TEST
               IMPLICIT NONE
         C
               INTEGER         N
               PARAMETER      (N = 9)
         C
               INTEGER         I
               REAL            PI, X(N), WSAVE(3 * N + 15)
         C
               EXTERNAL        COST, COSTI
               INTRINSIC       ACOS, COS
         C
         C     Initialize the array X to an even sequence, that is, it can be
         C     expanded in terms of a trigonometric series that contains only
         C     cosine terms.
         C
               PI = ACOS (-1.0)
               DO 100, I=1, N
                 X(I) = COS ((I - 1.0) * 2.0 * PI / (N - 1.0))
           100 CONTINUE
         C
               CALL COSTI (N, WSAVE)
               PRINT 1000
               PRINT 1010, (X(I), I = 1, N)
               CALL COST (N, X, WSAVE)
               PRINT 1020
               PRINT 1010, (X(I), I = 1, N)
               CALL COST (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: ')
               END
    
    SAMPLE OUTPUT
          Original Sequence:
            1.0   0.7   0.0  -0.7  -1.0  -0.7   0.0   0.7   1.0
          Transformed Sequence:
            0.0   0.0   8.0   0.0   0.0   0.0   0.0   0.0   0.0
          Recovered Sequence:
           16.0  11.3   0.0 -11.3 -16.0 -11.3   0.0  11.3  16.0
    
    
    
    


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