From c8377117389554c8e914052a46b03aa8bcae8364 Mon Sep 17 00:00:00 2001
From: John Darrington <john@darrington.wattle.id.au>
Date: Sun, 4 Oct 2009 16:51:57 +0200
Subject: [PATCH] CORRELATIONS: Properly deal with case weights.

Corrected a bug in the weighted covariance calculations,
and add a test to check that weights are properly
handled.
---
 src/math/covariance.c        |  2 +-
 tests/command/correlation.sh | 76 ++++++++++++++++++++++++++++++++++--
 2 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/src/math/covariance.c b/src/math/covariance.c
index b2d43427..ba0de0b6 100644
--- a/src/math/covariance.c
+++ b/src/math/covariance.c
@@ -153,7 +153,7 @@ covariance_accumulate (struct covariance *cov, const struct ccase *c)
 	  idx = cm_idx (cov, i, j);
 	  if (idx >= 0)
 	    {
-	      cov->cm [idx] += val1->f * val2->f;
+	      cov->cm [idx] += val1->f * val2->f * weight;
 	    }
 
 	  for (m = 0 ; m < n_MOMENTS; ++m)
diff --git a/tests/command/correlation.sh b/tests/command/correlation.sh
index bdc74939..d8fcb1cb 100755
--- a/tests/command/correlation.sh
+++ b/tests/command/correlation.sh
@@ -57,7 +57,7 @@ mkdir -p $TEMPDIR
 
 cd $TEMPDIR
 
-activity="create program"
+activity="create program 1"
 cat << EOF > $TESTFILE
 set format = F11.3.
 data list notable list /foo * bar * wiz * bang *.
@@ -93,13 +93,12 @@ EOF
 if [ $? -ne 0 ] ; then no_result ; fi
 
 
-activity="run program"
+activity="run program 1"
 $SUPERVISOR $PSPP --testing-mode -o raw-ascii $TESTFILE
 if [ $? -ne 0 ] ; then no_result ; fi
 
-activity="compare results"
+activity="compare results 1"
 perl -pi -e 's/^\s*$//g' $TEMPDIR/pspp.list
-cp $TEMPDIR/pspp.list /tmp
 diff -b  $TEMPDIR/pspp.list - << EOF
 1.1 CORRELATIONS.  Correlations
 #========================#=====#=====#=====#=====#
@@ -150,4 +149,73 @@ diff -b  $TEMPDIR/pspp.list - << EOF
 EOF
 if [ $? -ne 0 ] ; then fail ; fi
 
+
+# Now test that weights are properly handled.
+
+activity="create program 2"
+cat << EOF > $TESTFILE
+set format = F11.3.
+data list notable list /foo * bar * wiz * bang * w *.
+begin data.
+1   0   3   1  1
+3   9 -50   5  2
+3   4   3 203  1
+4  -9   0  -4  1
+98 78 104   2  3
+3  50 -49 200  1
+end data.
+
+weight by w.
+
+correlations 
+	variables = foo bar wiz bang
+	/statistics=descriptives xprod
+	.
+
+EOF
+if [ $? -ne 0 ] ; then no_result ; fi
+
+
+activity="run program 2"
+$SUPERVISOR $PSPP --testing-mode -o raw-ascii $TESTFILE
+if [ $? -ne 0 ] ; then no_result ; fi
+
+activity="copy results"
+cp $TEMPDIR/pspp.list $TEMPDIR/weighted
+if [ $? -ne 0 ] ; then no_result ; fi
+
+activity="create program 3"
+cat << EOF > $TESTFILE
+set format = F11.3.
+data list notable list /foo * bar * wiz * bang * w *.
+begin data.
+1   0   3   1  1
+3   9 -50   5  1
+3   9 -50   5  1
+3   4   3 203  1
+4  -9   0  -4  1
+98 78 104   2  1
+98 78 104   2  1
+98 78 104   2  1
+3  50 -49 200  1
+end data.
+
+weight by w.
+
+correlations 
+	variables = foo bar wiz bang
+	/statistics=descriptives xprod
+	.
+
+EOF
+if [ $? -ne 0 ] ; then no_result ; fi
+
+activity="run program 3"
+$SUPERVISOR $PSPP --testing-mode -o raw-ascii $TESTFILE
+if [ $? -ne 0 ] ; then no_result ; fi
+
+activity="Compare weighted and unweighted results"
+diff $TEMPDIR/pspp.list $TEMPDIR/weighted
+if [ $? -ne 0 ] ; then fail ; fi
+
 pass;
-- 
2.30.2