[n,c,ch,wa,ifac]=rfftf1(n,c,ch,wa,ifac);

function [n,c,ch,wa,ifac]=rfftf1(n,c,ch,wa,ifac);
persistent i idl1 ido ip iw ix2 ix3 ix4 k1 kh l1 l2 na nf ; 

if isempty(i), i=0; end;
if isempty(idl1), idl1=0; end;
if isempty(ido), ido=0; end;
if isempty(ip), ip=0; end;
if isempty(iw), iw=0; end;
if isempty(ix2), ix2=0; end;
if isempty(ix3), ix3=0; end;
if isempty(ix4), ix4=0; end;
if isempty(k1), k1=0; end;
if isempty(kh), kh=0; end;
if isempty(l1), l1=0; end;
if isempty(l2), l2=0; end;
if isempty(na), na=0; end;
if isempty(nf), nf=0; end;
%***BEGIN PROLOGUE  RFFTF1
%***PURPOSE  Compute the forward transform of a real, periodic sequence.
%***LIBRARY   SLATEC (FFTPACK)
%***CATEGORY  J1A1
%***TYPE      SINGLE PRECISION (RFFTF1-S, CFFTF1-C)
%***KEYWORDS  FFTPACK, FOURIER TRANSFORM
%***AUTHOR  Swarztrauber, P. N., (NCAR)
%***DESCRIPTION
%
%   subroutine RFFTF1 computes the Fourier coefficients of a real
%   periodic sequence (Fourier analysis).  The transform is defined
%   below at output parameter C.
%
%   The arrays WA and IFAC which are used by subroutine RFFTB1 must be
%   initialized by calling subroutine RFFTI1.
%
%   Input Arguments
%
%   N       the length of the array R to be transformed.  The method
%           is most efficient when N is a product of small primes.
%           N may change so long as different work arrays are provided.
%
%   C       a real array of length N which contains the sequence
%           to be transformed.
%
%   CH      a real work array of length at least N.
%
%   WA      a real work array which must be dimensioned at least N.
%
%   IFAC    an integer work array which must be dimensioned at least 15.
%
%           The WA and IFAC arrays must be initialized by calling
%           subroutine RFFTI1, and different WA and IFAC arrays must be
%           used for each different value of N.  This initialization
%           does not have to be repeated so long as N remains unchanged.
%           Thus subsequent transforms can be obtained faster than the
%           first.  The same WA and IFAC arrays can be used by RFFTF1
%           and RFFTB1.
%
%   Output Argument
%
%   C       C(1) = the sum from I=1 to I=N of R(I)
%
%           If N is even set L = N/2; if N is odd set L = (N+1)/2
%
%             then for K = 2,...,L
%
%                C(2*K-2) = the sum from I = 1 to I = N of
%
%                     C(I)*COS((K-1)*(I-1)*2*PI/N)
%
%                C(2*K-1) = the sum from I = 1 to I = N of
%
%                    -C(I)*SIN((K-1)*(I-1)*2*PI/N)
%
%           If N is even
%
%                C(N) = the sum from I = 1 to I = N of
%
%                     (-1)**(I-1)*C(I)
%
%   Notes:  This transform is unnormalized since a call of RFFTF1
%           followed by a call of RFFTB1 will multiply the input
%           sequence by N.
%
%           WA and IFAC contain initialization calculations which must
%           not be destroyed between calls of subroutine RFFTF1 or
%           RFFTB1.
%
%***REFERENCES  P. N. Swarztrauber, Vectorizing the FFTs, in Parallel
%                 Computations (G. Rodrigue, ed.), Academic Press,
%                 1982, pp. 51-83.
%***ROUTINES CALLED  RADF2, RADF3, RADF4, RADF5, RADFG
%***REVISION HISTORY  (YYMMDD)
%   790601  DATE WRITTEN
%   830401  Modified to use SLATEC library source file format.
%   860115  Modified by Ron Boisvert to adhere to Fortran 77 by
%           changing dummy array size declarations (1) to (*).
%   881128  Modified by Dick Valent to meet prologue standards.
%   891214  Prologue converted to Version 4.0 format.  (BAB)
%   900131  Routine changed from subsidiary to user-callable.  (WRB)
%   920501  Reformatted the REFERENCES section.  (WRB)
%***end PROLOGUE  RFFTF1
ch_shape=size(ch);ch=reshape(ch,1,[]);
c_shape=size(c);c=reshape(c,1,[]);
wa_shape=size(wa);wa=reshape(wa,1,[]);
ifac_shape=size(ifac);ifac=reshape(ifac,1,[]);
%***FIRST EXECUTABLE STATEMENT  RFFTF1
nf = fix(ifac(2));
na = 1;
l2 = fix(n);
iw = fix(n);
for k1 = 1 : nf;
kh = fix(nf - k1);
ip = fix(ifac(kh+3));
l1 = fix(fix(l2./ip));
ido = fix(fix(n./l2));
idl1 = fix(ido.*l1);
iw = fix(iw -(ip-1).*ido);
na = fix(1 - na);
if( ip==4 )
ix2 = fix(iw + ido);
ix3 = fix(ix2 + ido);
if( na~=0 )
[ido,l1,ch,c,dumvar5,dumvar6,dumvar7]=radf4(ido,l1,ch,c,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end),wa(sub2ind(size(wa),max(ix3,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));dumvar7i=find((wa(sub2ind(size(wa),max(ix3,1)):end))~=(dumvar7));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); wa(ix3-1+dumvar7i)=dumvar7(dumvar7i); 
else;
[ido,l1,c,ch,dumvar5,dumvar6,dumvar7]=radf4(ido,l1,c,ch,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end),wa(sub2ind(size(wa),max(ix3,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));dumvar7i=find((wa(sub2ind(size(wa),max(ix3,1)):end))~=(dumvar7));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); wa(ix3-1+dumvar7i)=dumvar7(dumvar7i); 
end;
elseif( ip~=2 ) ;
if( ip==3 )
ix2 = fix(iw + ido);
if( na~=0 )
[ido,l1,ch,c,dumvar5,dumvar6]=radf3(ido,l1,ch,c,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); 
else;
[ido,l1,c,ch,dumvar5,dumvar6]=radf3(ido,l1,c,ch,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); 
end;
elseif( ip~=5 ) ;
if( ido==1 )
na = fix(1 - na);
end;
if( na~=0 )
ch_orig=ch; ch_orig=ch; c_orig=c;    [ido,ip,l1,idl1,ch,dumvar6,dumvar7,c,dumvar9,wa(sub2ind(size(wa),max(iw,1)):end)]=radfg(ido,ip,l1,idl1,ch,ch,ch,c,c,wa(sub2ind(size(wa),max(iw,1)):end));    c(dumvar9~=c_orig)=dumvar9(dumvar9~=c_orig); ch(dumvar7~=ch_orig)=dumvar7(dumvar7~=ch_orig); ch(dumvar6~=ch_orig)=dumvar6(dumvar6~=ch_orig);
na = 0;
else;
c_orig=c; c_orig=c; ch_orig=ch;    [ido,ip,l1,idl1,c,dumvar6,dumvar7,ch,dumvar9,wa(sub2ind(size(wa),max(iw,1)):end)]=radfg(ido,ip,l1,idl1,c,c,c,ch,ch,wa(sub2ind(size(wa),max(iw,1)):end));    ch(dumvar9~=ch_orig)=dumvar9(dumvar9~=ch_orig); c(dumvar7~=c_orig)=dumvar7(dumvar7~=c_orig); c(dumvar6~=c_orig)=dumvar6(dumvar6~=c_orig);
na = 1;
end;
else;
ix2 = fix(iw + ido);
ix3 = fix(ix2 + ido);
ix4 = fix(ix3 + ido);
if( na~=0 )
[ido,l1,ch,c,dumvar5,dumvar6,dumvar7,dumvar8]=radf5(ido,l1,ch,c,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end),wa(sub2ind(size(wa),max(ix3,1)):end),wa(sub2ind(size(wa),max(ix4,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));dumvar7i=find((wa(sub2ind(size(wa),max(ix3,1)):end))~=(dumvar7));dumvar8i=find((wa(sub2ind(size(wa),max(ix4,1)):end))~=(dumvar8));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); wa(ix3-1+dumvar7i)=dumvar7(dumvar7i); wa(ix4-1+dumvar8i)=dumvar8(dumvar8i); 
else;
[ido,l1,c,ch,dumvar5,dumvar6,dumvar7,dumvar8]=radf5(ido,l1,c,ch,wa(sub2ind(size(wa),max(iw,1)):end),wa(sub2ind(size(wa),max(ix2,1)):end),wa(sub2ind(size(wa),max(ix3,1)):end),wa(sub2ind(size(wa),max(ix4,1)):end));   dumvar5i=find((wa(sub2ind(size(wa),max(iw,1)):end))~=(dumvar5));dumvar6i=find((wa(sub2ind(size(wa),max(ix2,1)):end))~=(dumvar6));dumvar7i=find((wa(sub2ind(size(wa),max(ix3,1)):end))~=(dumvar7));dumvar8i=find((wa(sub2ind(size(wa),max(ix4,1)):end))~=(dumvar8));   wa(iw-1+dumvar5i)=dumvar5(dumvar5i); wa(ix2-1+dumvar6i)=dumvar6(dumvar6i); wa(ix3-1+dumvar7i)=dumvar7(dumvar7i); wa(ix4-1+dumvar8i)=dumvar8(dumvar8i); 
end;
end;
elseif( na~=0 ) ;
[ido,l1,ch,c,wa(sub2ind(size(wa),max(iw,1)):end)]=radf2(ido,l1,ch,c,wa(sub2ind(size(wa),max(iw,1)):end));
else;
[ido,l1,c,ch,wa(sub2ind(size(wa),max(iw,1)):end)]=radf2(ido,l1,c,ch,wa(sub2ind(size(wa),max(iw,1)):end));
end;
l2 = fix(l1);
end; k1 = fix(nf+1);
if( na==1 )
ch_shape=zeros(ch_shape);ch_shape(:)=ch(1:numel(ch_shape));ch=ch_shape;
c_shape=zeros(c_shape);c_shape(:)=c(1:numel(c_shape));c=c_shape;
wa_shape=zeros(wa_shape);wa_shape(:)=wa(1:numel(wa_shape));wa=wa_shape;
ifac_shape=zeros(ifac_shape);ifac_shape(:)=ifac(1:numel(ifac_shape));ifac=ifac_shape;
return;
end;
for i = 1 : n;
c(i) = ch(i);
end; i = fix(n+1);
ch_shape=zeros(ch_shape);ch_shape(:)=ch(1:numel(ch_shape));ch=ch_shape;
c_shape=zeros(c_shape);c_shape(:)=c(1:numel(c_shape));c=c_shape;
wa_shape=zeros(wa_shape);wa_shape(:)=wa(1:numel(wa_shape));wa=wa_shape;
ifac_shape=zeros(ifac_shape);ifac_shape(:)=ifac(1:numel(ifac_shape));ifac=ifac_shape;
end
%DECK RFFTF