Merged master 8748

2018-08-05 11:33:30 -04:00
parent 8f8772f1bd
commit 62899069bf
1222 changed files with 70382 additions and 406763 deletions
@@ -0,0 +1,48 @@
+subroutine encode204(message,codeword)
+! Encode an 68-bit message and return a 204-bit codeword. 
+! The generator matrix has dimensions (136,68). 
+! The code is a (204,68) regular ldpc code with column weight 3.
+! The code was generated using the PEG algorithm.
+! After creating the codeword, the columns are re-ordered according to 
+! "colorder" to make the codeword compatible with the parity-check matrix 
+!
+
+include "ldpc_204_68_params.f90"
+
+integer*1 codeword(N)
+integer*1 gen(M,K)
+integer*1 itmp(N)
+integer*1 message(K)
+integer*1 pchecks(M)
+logical first
+data first/.true./
+
+save first,gen
+
+if( first ) then ! fill the generator matrix
+  gen=0
+  do i=1,M
+    do j=1,17
+      read(g(i)(j:j),"(Z1)") istr
+        do jj=1, 4
+          icol=(j-1)*4+jj
+          if( btest(istr,4-jj) ) gen(i,icol)=1
+        enddo
+    enddo
+  enddo
+first=.false.
+endif
+
+do i=1,M
+  nsum=0
+  do j=1,K 
+    nsum=nsum+message(j)*gen(i,j)
+  enddo
+  pchecks(i)=mod(nsum,2)
+enddo
+itmp(1:M)=pchecks
+itmp(M+1:N)=message(1:K)
+codeword(colorder+1)=itmp(1:N)
+
+return
+end subroutine encode204