Rename msksim.f90 to ldpcsim.f90.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6570 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/ldpc/Makefile.msk_osx

@@ -1,5 +1,4 @@
 # Compilers
-# $(CC) -DRAND_FILE=\"`pwd`/randfile\" rand.c
 CC = gcc
 CXX = g++
 FC = gfortran
@@ -24,14 +23,14 @@ CFLAGS = -O2 -I.
 %.o: %.F90
 	${FC} ${FFLAGS} -c $<
 
-all:	msksim
+all:	ldpcsim
 
-OBJS = msksim.o alloc.o rcode.o dec.o enc.o \
+OBJS = ldpcsim.o alloc.o rcode.o dec.o enc.o \
 	intio.o blockio.o check.o open.o mod2dense.o \
 	mod2sparse.o mod2convert.o distrib.o rand.o gran.o
 
-msksim:	$(OBJS)
-	$(FC) -o msksim $(OBJS) 
+ldpcsim:$(OBJS)
+	$(FC) -o ldpcsim $(OBJS) 
 
 rand.o:
 	$(CC) $(CFLAGS) -DRAND_FILE=\"./randfile\" -c rand.c

lib/ldpc/ldpcsim.f90

@@ -0,0 +1,76 @@
+program msksim
+
+use, intrinsic :: iso_c_binding
+
+! To change to a new code, edit the following line and the filenames
+! that contain the parity check and generator matrices.
+parameter (N=198, M=126, K=72) ! M and N are global variables on the C side.
+
+character(50) pchk_file,gen_file
+integer(1) codeword(1:N), decoded(1:K), message(1:K)
+real*8 lratio(N), rxdata(N)
+
+pchk_file="./jtmode_codes/peg-198-72-reg4.pchk"
+gen_file="./jtmode_codes/peg-198-72-reg4.gen"
+
+rate=real(K)/real(N)
+
+call init_ldpc(trim(pchk_file)//char(0),trim(gen_file)//char(0))
+
+message(1:K/2)=1
+message((K/2+1):K)=0
+call ldpc_encode(message,codeword)
+
+max_iterations=50
+ntrials=1000000
+
+write(*,*) "Eb/N0   ngood    nundetected"
+do idb = 0, 11
+  db=idb/2.0-0.5
+  sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
+
+  ngood=0
+  nue=0
+
+  do itrial=1, ntrials
+
+    do i=1,N
+      rxdata(i) = 2.0*(codeword(i)-0.5) + sigma*gran()
+    enddo
+
+! correct signal normalization is important for this decoder.
+    rxav=sum(rxdata)/N
+    rx2av=sum(rxdata*rxdata)/N
+    rxsig=sqrt(rx2av-rxav*rxav)
+    rxdata=rxdata/rxsig
+
+! s can be tuned to trade a few tenth's dB of threshold 
+! for an order of magnitude in UER 
+    do i=1,N
+      s=0.75
+      lratio(i)=exp(2.0*rxdata(i)/(s*s))
+    enddo
+
+    call ldpc_decode(lratio, decoded, max_iterations, niterations)
+
+    if( niterations .ge. 0 ) then
+      nueflag=0
+      do i=1,K
+        if( message(i) .ne. decoded(i) ) then
+          nueflag=1
+        endif
+      enddo
+      if( nueflag .eq. 1 ) then
+        nue=nue+1
+      else
+        ngood=ngood+1;
+      endif
+    endif
+
+  enddo
+
+  write(*,"(f4.1,1x,i8,1x,i8)") db,ngood,nue
+
+enddo
+
+end program msksim

lib/ldpc/peg/leftHandGirth.log

@@ -1 +0,0 @@
-inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf inf 20 12 12 12 12 12 12 12 12 10 10 10 10 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6