SUBROUTINE COSQB(N,X,WSAVE)
C***BEGIN PROLOGUE  COSQB
C***DATE WRITTEN   790601   (YYMMDD)
C***REVISION DATE  830401   (YYMMDD)
C***CATEGORY NO.  J1A3
C***KEYWORDS  FOURIER TRANSFORM
C***AUTHOR  SWARZTRAUBER, P. N., (NCAR)
C***PURPOSE  Unnormalized inverse of COSQF.
C***DESCRIPTION
C
C  Subroutine COSQB computes the fast Fourier transform of quarter
C  wave data. That is, COSQB computes a sequence from its
C  representation in terms of a cosine series with odd wave numbers.
C  The transform is defined below at output parameter X.
C
C  COSQB is the unnormalized inverse of COSQF since a call of COSQB
C  followed by a call of COSQF will multiply the input sequence X
C  by 4*N.
C
C  The array WSAVE which is used by subroutine COSQB must be
C  initialized by calling subroutine COSQI(N,WSAVE).
C
C
C  Input Parameters
C
C  N       the length of the array X to be transformed.  The method
C          is most efficient when N is a product of small primes.
C
C  X       an array which contains the sequence to be transformed
C
C  WSAVE   a work array that must be dimensioned at least 3*N+15
C          in the program that calls COSQB.  The WSAVE array must be
C          initialized by calling subroutine COSQI(N,WSAVE), and a
C          different WSAVE array must be used for each different
C          value of N.  This initialization does not have to be
C          repeated so long as N remains unchanged.  Thus subsequent
C          transforms can be obtained faster than the first.
C
C  Output Parameters
C
C  X       For I=1,...,N
C
C               X(I)= the sum from K=1 to K=N of
C
C                 4*X(K)*COS((2*K-1)*(I-1)*PI/(2*N))
C
C               A call of COSQB followed by a call of
C               COSQF will multiply the sequence X by 4*N.
C               Therefore COSQF is the unnormalized inverse
C               of COSQB.
C
C  WSAVE   contains initialization calculations which must not
C          be destroyed between calls of COSQB or COSQF.
C***REFERENCES  (NONE)
C***ROUTINES CALLED  COSQB1
C***END PROLOGUE  COSQB