mirror of https://github.com/saitohirga/WSJT-X.git
Implement AP decoding for JT65 (VHF/UHF/Microwave only).
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8277 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke
parent
6eeece9a4b
commit
e90cc846bb
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@ -604,7 +604,7 @@ set (qra_CSRCS
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set (wsjt_CSRCS
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${ka9q_CSRCS}
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lib/ftrsd/ftrsd2.c
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lib/ftrsd/ftrsdap.c
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lib/sgran.c
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lib/golay24_table.c
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lib/gran.c
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@ -21,7 +21,8 @@ subroutine decode65b(s2,nflip,nadd,mode65,ntrials,naggressive,ndepth, &
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enddo
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call extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
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hiscall,hisgrid,nexp_decode,ncount,nhist,decoded,ltext,nft,qual)
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hiscall,hisgrid,nQSOProgress,ljt65apon,nexp_decode,ncount, &
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nhist,decoded,ltext,nft,qual)
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! Suppress "birdie messages" and other garbage decodes:
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if(decoded(1:7).eq.'000AAA ') ncount=-1
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@ -366,7 +366,7 @@ contains
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endif
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nap=ishft(ft,-2)
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if(nap.ne.0) then
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write(cflags(1:3),'(a1,i2.2)') 'a',nap
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write(cflags(1:3),'(a1,i1)') 'a',nap
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endif
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endif
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csync='# '
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123
lib/extract.f90
123
lib/extract.f90
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@ -1,6 +1,7 @@
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subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
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mycall_12,hiscall_12,hisgrid,nexp_decode,ncount,nhist,decoded, &
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ltext,nft,qual)
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mycall_12,hiscall_12,hisgrid,nQSOProgress,ljt65apon, &
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nexp_decode,ncount, &
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nhist,decoded,ltext,nft,qual)
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! Input:
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! s3 64-point spectra for each of 63 data symbols
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@ -20,19 +21,73 @@ subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
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use timer_module, only: timer
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real s3(64,63)
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character decoded*22
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character decoded*22, apmessage*22
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character*12 mycall_12,hiscall_12
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character*6 mycall,hiscall,hisgrid
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character*6 mycall0,hiscall0,hisgrid0
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integer apsymbols(5,12),ap(12)
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integer nappasses(0:5) ! the number of decoding passes to use for each QSO state
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integer naptypes(0:5,4) ! (nQSOProgress, decoding pass) maximum of 4 passes for now
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integer dat4(12)
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integer mrsym(63),mr2sym(63),mrprob(63),mr2prob(63)
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integer correct(63),tmp(63)
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logical ltext
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logical first,ltext,ljt65apon
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common/chansyms65/correct
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data first/.true./
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save
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if(mode65.eq.-99) stop !Silence compiler warning
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if(first) then
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! aptype
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!------------------------
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! 1 CQ ??? ???
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! 2 MyCall ??? ???
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! 3 MyCall DxCall ???
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! 4 MyCall DxCall RRR
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! 5 MyCall DxCall 73
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apsymbols=-1
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nappasses=(/2,2,2,3,3,3/)
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naptypes(0,1:4)=(/1,2,0,0/)
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naptypes(1,1:4)=(/2,3,0,0/)
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naptypes(2,1:4)=(/2,3,0,0/)
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naptypes(3,1:4)=(/3,4,5,0/)
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naptypes(4,1:4)=(/3,4,5,0/)
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naptypes(5,1:4)=(/3,1,2,0/)
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first=.false.
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endif
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mycall=mycall_12(1:6)
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hiscall=hiscall_12(1:6)
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! Fill apsymbols array
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if(ljt65apon .and. (mycall.ne.mycall0 .or. hiscall.ne.hiscall0)) then
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!write(*,*) 'initializing apsymbols '
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apsymbols=-1
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mycall0=mycall
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hiscall0=hiscall
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ap=-1
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apsymbols(1,1:4)=(/62,32,32,49/) ! CQ
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if(len_trim(mycall).gt.0) then
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apmessage=mycall//" "//mycall//" RRR"
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call packmsg(apmessage,ap,itype,.false.)
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if(itype.ne.1) ap=-1
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apsymbols(2,1:4)=ap(1:4)
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!write(*,*) 'mycall symbols ',ap(1:4)
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if(len_trim(hiscall).gt.0) then
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apmessage=mycall//" "//hiscall//" RRR"
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call packmsg(apmessage,ap,itype,.false.)
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if(itype.ne.1) ap=-1
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apsymbols(3,1:9)=ap(1:9)
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apsymbols(4,:)=ap
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apmessage=mycall//" "//hiscall//" 73"
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call packmsg(apmessage,ap,itype,.false.)
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if(itype.ne.1) ap=-1
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apsymbols(5,:)=ap
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endif
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endif
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endif
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qual=0.
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nbirdie=20
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npct=50
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@ -71,28 +126,48 @@ subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
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call graycode65(mr2sym,63,-1) !Remove gray code and interleaving
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call interleave63(mr2sym,-1) !from second-most-reliable symbols
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call interleave63(mr2prob,-1)
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ntry=0
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!call gf64_osd(mrsym,mrprob,mr2sym,mr2prob,correct)
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call timer('ftrsd ',0)
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param=0
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call ftrsd2(mrsym,mrprob,mr2sym,mr2prob,ntrials,correct,param,ntry)
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call timer('ftrsd ',1)
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ncandidates=param(0)
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nhard=param(1)
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nsoft=param(2)
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nerased=param(3)
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rtt=0.001*param(4)
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ntotal=param(5)
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qual=0.001*param(7)
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nd0=81
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r0=0.87
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if(naggressive.eq.10) then
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nd0=83
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r0=0.90
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npass=1 ! if ap decoding is disabled
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if(ljt65apon .and. len_trim(mycall).gt.0) then
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npass=1+nappasses(nQSOProgress)
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!write(*,*) 'ap is on: ',npass-1,'ap passes of types ',naptypes(nQSOProgress,:)
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endif
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if(ntotal.le.nd0 .and. rtt.le.r0) nft=1
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do ipass=1,npass
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ap=-1
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ntype=0
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if(ipass.gt.1) then
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ntype=naptypes(nQSOProgress,ipass-1)
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!write(*,*) 'ap pass, type ',ntype
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ap=apsymbols(ntype,:)
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if(count(ap.ge.0).eq.0) cycle ! don't bother if all ap symbols are -1
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!write(*,'(12i3)') ap
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endif
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ntry=0
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call timer('ftrsd ',0)
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param=0
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call ftrsdap(mrsym,mrprob,mr2sym,mr2prob,ap,ntrials,correct,param,ntry)
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call timer('ftrsd ',1)
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ncandidates=param(0)
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nhard=param(1)
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nsoft=param(2)
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nerased=param(3)
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rtt=0.001*param(4)
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ntotal=param(5)
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qual=0.001*param(7)
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nd0=81
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r0=0.87
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if(naggressive.eq.10) then
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nd0=83
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r0=0.90
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endif
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if(ntotal.le.nd0 .and. rtt.le.r0) then
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nft=1+ishft(ntype,2)
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endif
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if(nft.gt.0) exit
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enddo
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!write(*,*) nft
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if(nft.eq.0 .and. iand(ndepth,32).eq.32) then
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qmin=2.0 - 0.1*naggressive
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call timer('hint65 ',0)
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@ -0,0 +1,227 @@
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/*
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ftrsdap.c
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A soft-decision decoder for the JT65 (63,12) Reed-Solomon code.
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This decoding scheme is built around Phil Karn's Berlekamp-Massey
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errors and erasures decoder. The approach is inspired by a number of
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publications, including the stochastic Chase decoder described
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in "Stochastic Chase Decoding of Reed-Solomon Codes", by Leroux et al.,
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IEEE Communications Letters, Vol. 14, No. 9, September 2010 and
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"Soft-Decision Decoding of Reed-Solomon Codes Using Successive Error-
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and-Erasure Decoding," by Soo-Woong Lee and B. V. K. Vijaya Kumar.
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Steve Franke K9AN and Joe Taylor K1JT
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <time.h>
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#include <string.h>
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#include "../ftrsd/rs2.h"
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static void *rs;
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void getpp_(int workdat[], float *pp);
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void ftrsdap_(int mrsym[], int mrprob[], int mr2sym[], int mr2prob[],
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int ap[], int* ntrials0, int correct[], int param[], int ntry[])
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{
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int rxdat[63], rxprob[63], rxdat2[63], rxprob2[63];
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int workdat[63];
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int indexes[63];
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int era_pos[51];
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int i, j, numera, nerr, nn=63;
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int ntrials = *ntrials0;
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int nhard=0,nhard_min=32768,nsoft=0,nsoft_min=32768;
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int ntotal=0,ntotal_min=32768,ncandidates;
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int nera_best=0;
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float pp,pp1,pp2;
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static unsigned int nseed;
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// Power-percentage symbol metrics - composite gnnf/hf
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int perr[8][8] = {
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{ 4, 9, 11, 13, 14, 14, 15, 15},
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{ 2, 20, 20, 30, 40, 50, 50, 50},
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{ 7, 24, 27, 40, 50, 50, 50, 50},
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{13, 25, 35, 46, 52, 70, 50, 50},
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{17, 30, 42, 54, 55, 64, 71, 70},
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{25, 39, 48, 57, 64, 66, 77, 77},
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{32, 45, 54, 63, 66, 75, 78, 83},
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{51, 58, 57, 66, 72, 77, 82, 86}};
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// Initialize the KA9Q Reed-Solomon encoder/decoder
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unsigned int symsize=6, gfpoly=0x43, fcr=3, prim=1, nroots=51;
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rs=init_rs_int(symsize, gfpoly, fcr, prim, nroots, 0);
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// Reverse the received symbol vectors for BM decoder
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for (i=0; i<63; i++) {
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rxdat[i]=mrsym[62-i];
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rxprob[i]=mrprob[62-i];
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rxdat2[i]=mr2sym[62-i];
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rxprob2[i]=mr2prob[62-i];
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}
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// Set ap symbols and ap mask
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for (i=0; i<12; i++) {
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if(ap[i]>=0) {
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rxdat[11-i]=ap[i];
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rxprob2[11-i]=-1;
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}
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}
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// Sort rxprob to find indexes of the least reliable symbols
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int k, pass, tmp, nsym=63;
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int probs[63];
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for (i=0; i<63; i++) {
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indexes[i]=i;
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probs[i]=rxprob[i];
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}
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for (pass = 1; pass <= nsym-1; pass++) {
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for (k = 0; k < nsym - pass; k++) {
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if( probs[k] < probs[k+1] ) {
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tmp = probs[k];
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probs[k] = probs[k+1];
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probs[k+1] = tmp;
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tmp = indexes[k];
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indexes[k] = indexes[k+1];
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indexes[k+1] = tmp;
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}
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}
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}
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// See if we can decode using BM HDD, and calculate the syndrome vector.
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memset(era_pos,0,51*sizeof(int));
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numera=0;
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memcpy(workdat,rxdat,sizeof(rxdat));
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nerr=decode_rs_int(rs,workdat,era_pos,numera,1);
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if( nerr >= 0 ) {
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// Hard-decision decoding succeeded. Save codeword and some parameters.
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nhard=0;
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for (i=0; i<63; i++) {
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if( workdat[i] != rxdat[i] ) nhard=nhard+1;
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}
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memcpy(correct,workdat,63*sizeof(int));
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param[0]=0;
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param[1]=nhard;
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param[2]=0;
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param[3]=0;
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param[4]=0;
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param[5]=0;
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param[7]=1000*1000;
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ntry[0]=0;
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return;
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}
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/*
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Hard-decision decoding failed. Try the FT soft-decision method.
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Generate random erasure-locator vectors and see if any of them
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decode. This will generate a list of "candidate" codewords. The
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soft distance between each candidate codeword and the received
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word is estimated by finding the largest (pp1) and second-largest
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(pp2) outputs from a synchronized filter-bank operating on the
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symbol spectra, and using these to decide which candidate
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codeword is "best".
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*/
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nseed=1; //Seed for random numbers
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float ratio;
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int thresh, nsum;
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int thresh0[63];
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ncandidates=0;
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nsum=0;
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int ii,jj;
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for (i=0; i<nn; i++) {
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nsum=nsum+rxprob[i];
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j = indexes[62-i];
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if( rxprob2[j]>=0 ) {
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ratio = (float)rxprob2[j]/((float)rxprob[j]+0.01);
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ii = 7.999*ratio;
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jj = (62-i)/8;
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thresh0[i] = 1.3*perr[ii][jj];
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} else {
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thresh0[i] = 0.0;
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}
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//printf("%d %d %d\n",i,j,rxdat[i]);
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}
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if(nsum<=0) return;
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pp1=0.0;
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pp2=0.0;
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for (k=1; k<=ntrials; k++) {
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memset(era_pos,0,51*sizeof(int));
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memcpy(workdat,rxdat,sizeof(rxdat));
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/*
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Mark a subset of the symbols as erasures.
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Run through the ranked symbols, starting with the worst, i=0.
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NB: j is the symbol-vector index of the symbol with rank i.
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*/
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numera=0;
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for (i=0; i<nn; i++) {
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j = indexes[62-i];
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thresh=thresh0[i];
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long int ir;
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// Generate a random number ir, 0 <= ir < 100 (see POSIX.1-2001 example).
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nseed = nseed * 1103515245 + 12345;
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ir = (unsigned)(nseed/65536) % 32768;
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ir = (100*ir)/32768;
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if((ir < thresh ) && numera < 51) {
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era_pos[numera]=j;
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numera=numera+1;
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}
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}
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nerr=decode_rs_int(rs,workdat,era_pos,numera,0);
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if( nerr >= 0 ) {
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// We have a candidate codeword. Find its hard and soft distance from
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// the received word. Also find pp1 and pp2 from the full array
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// s3(64,63) of synchronized symbol spectra.
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ncandidates=ncandidates+1;
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nhard=0;
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nsoft=0;
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for (i=0; i<63; i++) {
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if(workdat[i] != rxdat[i]) {
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nhard=nhard+1;
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if(workdat[i] != rxdat2[i]) {
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nsoft=nsoft+rxprob[i];
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}
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}
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}
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nsoft=63*nsoft/nsum;
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ntotal=nsoft+nhard;
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getpp_(workdat,&pp);
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if(pp>pp1) {
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pp2=pp1;
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pp1=pp;
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nsoft_min=nsoft;
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nhard_min=nhard;
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ntotal_min=ntotal;
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memcpy(correct,workdat,63*sizeof(int));
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nera_best=numera;
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ntry[0]=k;
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} else {
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if(pp>pp2 && pp!=pp1) pp2=pp;
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}
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if(nhard_min <= 41 && ntotal_min <= 71) break;
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}
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if(k == ntrials) ntry[0]=k;
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}
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param[0]=ncandidates;
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param[1]=nhard_min;
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param[2]=nsoft_min;
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param[3]=nera_best;
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param[4]=1000.0*pp2/pp1;
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param[5]=ntotal_min;
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param[6]=ntry[0];
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param[7]=1000.0*pp2;
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param[8]=1000.0*pp1;
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if(param[0]==0) param[2]=-1;
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return;
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}
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@ -490,8 +490,9 @@ contains
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enddo
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nadd=nsum*ismo
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call extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
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hiscall,hisgrid,nexp_decode,ncount,nhist,decoded,ltext,nft,qual)
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call extract(s3c,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
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hiscall,hisgrid,nQSOProgress,ljt65apon,nexp_decode,ncount,nhist, &
|
||||
avemsg,ltext,nftt,qual)
|
||||
if(nftt.eq.1) then
|
||||
nsmo=ismo
|
||||
param(9)=nsmo
|
||||
|
|
|
|||
Loading…
Reference in New Issue