CountsPhraseProperty: add comment to header

1 files changed, 16 insertions, 0 deletions

diff --git a/moses/PP/CountsPhraseProperty.h b/moses/PP/CountsPhraseProperty.h
index 24e4eaa40..f633381b6 100644
--- a/moses/PP/CountsPhraseProperty.h
+++ b/moses/PP/CountsPhraseProperty.h
@@ -8,6 +8,22 @@
 namespace Moses
 {
 
+//    A simple phrase property class to access the three phrase count values.
+//
+//    The counts are usually not needed during decoding and are not loaded
+//    from the phrase table. This is just a workaround that can make them
+//    available to features which have a use for them.
+//
+//    If you need access to the counts, copy the two marginal counts and the
+//    joint count into an additional information property with key "Counts",
+//    e.g. using awk:
+//
+//    $ zcat phrase-table.gz | awk -F' \|\|\| '  '{printf("%s {{Counts %s}}\n",$0,$5);}' | gzip -c > phrase-table.withCountsPP.gz
+//
+//    CountsPhraseProperty reads them from the phrase table and provides
+//    methods GetSourceMarginal(), GetTargetMarginal(), GetJointCount().
+
+
 class CountsPhraseProperty : public PhraseProperty
 {
 public: