SUBROUTINE SINQF(N,X,WSAVE) C***BEGIN PROLOGUE SINQF 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 Forward sine transform with odd wave numbers. C***DESCRIPTION C C Subroutine SINQF computes the fast Fourier transform of quarter C wave data. That is, SINQF computes the coefficients in a sine C series representation with only odd wave numbers. The transform C is defined below at output parameter X. C C SINQB is the unnormalized inverse of SINQF since a call of SINQF C followed by a call of SINQB will multiply the input sequence X C by 4*N. C C The array WSAVE which is used by subroutine SINQF must be C initialized by calling subroutine SINQI(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 which must be dimensioned at least 3*N+15 C in the program that calls SINQF. The WSAVE array must be C initialized by calling subroutine SINQI(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) = (-1)**(I-1)*X(N) C C + the sum from K=1 to K=N-1 of C C 2*X(K)*SIN((2*I-1)*K*PI/(2*N)) C C A call of SINQF followed by a call of C SINQB will multiply the sequence X by 4*N. C Therefore SINQB is the unnormalized inverse C of SINQF. C C WSAVE contains initialization calculations which must not C be destroyed between calls of SINQF or SINQB. C***REFERENCES (NONE) C***ROUTINES CALLED COSQF C***END PROLOGUE SINQF