WSJT-X/lib/downsam9.f90
Bill Somerville 5b43b691f3 Restructuring in preparation for direct decoder invocation from wsjtx
Re-factor the JT4, JT65 and JT9 decoders as Fortran modules using type
bound  procedures, the  decoder types  implement a  callback procedure
such that he client of the decoder can interpret the decode results as
they need.

The JT4 decoder has a  second callback that delivers message averaging
status.  Also the  previously separate  source files  lib/jt4a.f90 and
lib/avg4.f90 have been merged  into lib/jt4_decode.f90 as private type
bound procedures of the new jt4_decoder type.

Re-factored the lib/decoder.f90 subroutine  to utilize the new decoder
types. Added local procedures to process decodes and averaging results
including the necessary OpenMP synchronization directives for parallel
JT9+JT65 decoding.

Added the  jt65_test module  which is  a basic  test harness  for JT65
decoding. Re-factored  the jt65 utility  to utilize the  new jt65_test
module.

Changed a  few integers  to logical variables  where their  meaning is
clearly binary.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6324 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2015-12-29 23:52:55 +00:00

89 lines
2.3 KiB
Fortran

subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2)
!Downsample from id2() into c2() so as to yield nspsd samples per symbol,
!mixing from fpk down to zero frequency. The downsample factor is 432.
use, intrinsic :: iso_c_binding
use FFTW3
use timer_module, only: timer
include 'constants.f90'
integer(C_SIZE_T) NMAX1
parameter (NMAX1=653184)
parameter (NFFT1=653184,NFFT2=1512)
type(C_PTR) :: plan !Pointers plan for big FFT
integer*2 id2(0:8*npts8-1)
logical, intent(inout) :: newdat
real*4, pointer :: x1(:)
complex c1(0:NFFT1/2)
complex c2(0:NFFT2-1)
real s(5000)
logical first
common/patience/npatience,nthreads
data first/.true./
save plan,first,c1,s,x1
df1=12000.0/NFFT1
npts=8*npts8
if(npts.gt.NFFT1) npts=NFFT1 !### Fix! ###
if(first) then
nflags=FFTW_ESTIMATE
if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
if(npatience.eq.2) nflags=FFTW_MEASURE
if(npatience.eq.3) nflags=FFTW_PATIENT
if(npatience.eq.4) nflags=FFTW_EXHAUSTIVE
! Plan the FFTs just once
!$omp critical(fftw) ! serialize non thread-safe FFTW3 calls
plan=fftwf_alloc_real(NMAX1)
call c_f_pointer(plan,x1,[NMAX1])
x1(0:NMAX1-1) => x1 !remap bounds
call fftwf_plan_with_nthreads(nthreads)
plan=fftwf_plan_dft_r2c_1d(NFFT1,x1,c1,nflags)
call fftwf_plan_with_nthreads(1)
!$omp end critical(fftw)
first=.false.
endif
if(newdat) then
x1(0:npts-1)=id2(0:npts-1)
x1(npts:NFFT1-1)=0. !Zero the rest of x1
call timer('FFTbig9 ',0)
call fftwf_execute_dft_r2c(plan,x1,c1)
call timer('FFTbig9 ',1)
nadd=int(1.0/df1)
s=0.
do i=1,5000
j=int((i-1)/df1)
do n=1,nadd
j=j+1
s(i)=s(i)+real(c1(j))**2 + aimag(c1(j))**2
enddo
enddo
newdat=.false.
endif
ndown=8*nsps8/nspsd !Downsample factor = 432
nh2=NFFT2/2
nf=nint(fpk)
i0=int(fpk/df1)
nw=100
ia=max(1,nf-nw)
ib=min(5000,nf+nw)
call pctile(s(ia),ib-ia+1,40,avenoise)
fac=sqrt(1.0/avenoise)
do i=0,NFFT2-1
j=i0+i
if(i.gt.nh2) j=j-NFFT2
c2(i)=fac*c1(j)
enddo
call four2a(c2,NFFT2,1,1,1) !FFT back to time domain
return
end subroutine downsam9