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Remove redundant copy of large array in JT9 decoder

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Also moved  the same large array  from stack to heap  which along with
other prior  changes now allows  the Windows jt9 OpenMP  executable to
run with a default stack size again.

This also removes a crash on the Mac version which was probably due to
excessive stack usage.

Net result is an even faster JT9 decoder.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4942 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Bill Somerville 2015-02-08 09:53:20 +00:00
parent c86f37cade
commit 127f72f3ad
2 changed files with 86 additions and 96 deletions
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3
CMakeLists.txt
View File

@ -743,9 +743,6 @@ qt5_use_modules (jt9 Core)
if (${OPENMP_FOUND})
add_executable (jt9_omp lib/jt9.f90 lib/jt9a.f90 lib/jt9b.f90 lib/jt9c.f90 ${jt9_CXXSRCS} wsjtx.rc)
if (WIN32)
set (_extra_omp_link_flags "-Wl,--stack,8388608")
endif (WIN32)
set_target_properties (jt9_omp
PROPERTIES
COMPILE_FLAGS "${OpenMP_C_FLAGS}"

19
lib/downsam9.f90
View File

@ -10,27 +10,19 @@ subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2,nz2)
parameter (NMAX1=604800)
type(C_PTR) :: plan !Pointers plan for big FFT
integer*2 id2(0:8*npts8-1)
real*4 x1(0:NMAX1-1)
real*4, pointer :: x1(:)
complex c1(0:NMAX1/2)
complex c2(0:1440-1)
real s(5000)
logical first
common/patience/npatience,nthreads
data first/.true./
save plan,first,c1,s
save plan,first,c1,s,x1
nfft1=NMAX1 !Forward FFT length
df1=12000.0/nfft1
npts=8*npts8
if(newdat.eq.1) then
fac=6.963e-6 !Why this weird constant?
do i=0,npts-1
x1(i)=fac*id2(i)
enddo
x1(npts:nfft1-1)=0. !Zero the rest of x1
endif
if(first) then
nflags=FFTW_ESTIMATE
if(npatience.eq.1) nflags=FFTW_ESTIMATE_PATIENT
@ -40,6 +32,9 @@ subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2,nz2)
! 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)
@ -50,9 +45,7 @@ subroutine downsam9(id2,npts8,nsps8,newdat,nspsd,fpk,c2,nz2)
if(newdat.eq.1) then
fac=6.963e-6 !Why this weird constant?
do i=0,npts-1
x1(i)=fac*id2(i)
enddo
x1(0:npts-1)=fac*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)