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Adding CNF variable mapping rules.

This commit is contained in:
Alan Mishchenko 2020-01-18 16:42:02 -08:00
parent 4853ae9cab
commit 19b8d9bf7c
1 changed files with 11 additions and 0 deletions
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11
src/base/io/io.c
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@ -2248,6 +2248,17 @@ usage:
fprintf( pAbc->Err, "\t-v : toggle printing verbose information [default = %s]\n", fVerbose? "yes" : "no" );
fprintf( pAbc->Err, "\t-h : print the help massage\n" );
fprintf( pAbc->Err, "\tfile : the name of the file to write\n" );
fprintf( pAbc->Err, "\n" );
fprintf( pAbc->Err, "\t CNF variable mapping rules:\n" );
fprintf( pAbc->Err, "\n" );
fprintf( pAbc->Err, "\t Assume CNF has N variables, with variable IDs running from 0 to N-1.\n" );
fprintf( pAbc->Err, "\t Variable number 0 is not used in the CNF.\n" );
fprintf( pAbc->Err, "\t Variables 1, 2, 3,... <nPOs> represent POs in their natural order.\n" );
fprintf( pAbc->Err, "\t Variables N-<nPIs>, N-<nPIs>+1, N-<nPIs>+2, ... N-1, represent PIs in their natural order.\n" );
fprintf( pAbc->Err, "\t The internal variables are ordered in a reverse topological order from outputs to inputs.\n" );
fprintf( pAbc->Err, "\t That is, smaller variable IDs tend to be closer to the outputs, while larger\n" );
fprintf( pAbc->Err, "\t variable IDs tend to be closer to the inputs. It was found that this ordering\n" );
fprintf( pAbc->Err, "\t leads to faster SAT solving for hard UNSAT CEC problems.\n" );
return 1;
}