Move FT8 files into their own directory.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8200 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/ft8/encode174.f90

@@ -0,0 +1,50 @@
+subroutine encode174(message,codeword)
+! Encode an 101-bit message and return a 174-bit codeword. 
+! The generator matrix has dimensions (73,101). 
+! The code is a (174,101) 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_174_87_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=1,11
+      read(g(i)( (j-1)*2+1:(j-1)*2+2 ),"(Z2)") istr
+        do jj=1, 8
+          icol=(j-1)*8+jj
+          if( icol .le. 87 ) then
+            if( btest(istr,8-jj) ) gen(i,icol)=1
+          endif
+        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 encode174