C
C
C                    * * * * * * * * * * * * * * * *
C                    *                             *
C                    * SUBROUTINE VRFFTI(N,WSAVE)  *
C                    *                             *
C                    * * * * * * * * * * * * * * * *
C
C
C     SUBROUTINE VRFFTI INITIALIZES THE ARRAY WSAVE THAT IS USED IN
C     BOTH VRFFTF AND VRFFTB. THE PRIME FACTORIZATION OF N AND A
C     TABULATION OF CERTAIN TRIGONOMETRIC VALUES ARE COMPUTED AND STORED
C     IN THE ARRAY WSAVE.
C
C     INPUT PARAMETER
C
C     N       THE LENGTH OF THE SEQUENCE TO BE TRANSFORMED.  THERE IS NO
C             RESTRICTION ON N.
C
C     OUTPUT PARAMETER
C
C     WSAVE   A WORK ARRAY THAT MUST BE DIMENSIONED AT LEAST N+15.
C             THE SAME WORK ARRAY CAN BE USED FOR BOTH VRFFTF AND VRFFTB
C             AS LONG AS N REMAINS UNCHANGED.  DIFFERENT WSAVE ARRAYS
C             ARE REQUIRED FOR DIFFERENT VALUES OF N. THE CONTENTS OF
C             WSAVE MUST NOT BE CHANGED BETWEEN CALLS TO VRFFTF OR
C             VRFFTB.
C
C
C              * * * * * * * * * * * * * * * * * * * * *
C              *                                       *
C              *         PROGRAM SPECIFICATIONS        *
C              *                                       *
C              * * * * * * * * * * * * * * * * * * * * *
C
C
C
C     DIMENSION OF    R(MDIMR,N), RT(MDIMR,N), WSAVE(N+15)
C     ARGUMENTS
C
C     LATEST          AUGUST 1, 1985
C     REVISION
C
C     SUBPROGRAMS     VRFFTI, VRFTI1, VRFFTF, VRFTF1, VRADF2, VRADF3,
C     REQUIRED        VRADF4, VRADF5, VRADFG, VRFFTB, VRFTB1, VRADB2,
C                     VRADB3, VRADB4, VRADB5, VRADBG, PIMACH
C
C     SPECIAL         NONE
C     CONDITIONS
C
C     COMMON          NONE
C     BLOCKS
C
C     I/O             NONE
C
C     PRECISION       SINGLE
C
C     SPECIALIST      ROLAND SWEET
C
C     LANGUAGE        FORTRAN
C
C     HISTORY         WRITTEN BY LINDA LINDGREN AND ROLAND SWEET AT THE
C                     NATIONAL BUREAU OF STANDARDS (BOULDER).
C
C     ALGORITHM       A REAL VARIANT OF THE STOCKHAM AUTOSORT VERSION
C                     OF THE COOLEY-TUKEY FAST FOURIER TRANSFORM.
C
C     PORTABILITY     AMERICAN NATIONAL STANDARDS INSTITUTE FORTRAN 77.
C                     THE ONLY MACHINE DEPENDENT CONSTANT IS LOCATED IN
C                     THE FUNCTION PIMACH.
C
C     REQUIRED        COS,SIN
C     RESIDENT
C     ROUTINES
C
C