X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fmath%2Flevene.c;h=098fcc5a1ba9feba488060e3406f54f84364c998;hb=2a45a48f87553563cbf0f0b6dcc20396b3e5a27a;hp=fe04d294e1acfbf214dadea6a53717ccc9a37646;hpb=71eea20b080f51f1aa00ef35acf4f49ce742d10a;p=pspp

diff --git a/src/math/levene.c b/src/math/levene.c
index fe04d294e1..098fcc5a1b 100644
--- a/src/math/levene.c
+++ b/src/math/levene.c
@@ -22,6 +22,7 @@
 #include "libpspp/misc.h"
 #include "libpspp/hmap.h"
 #include "data/value.h"
+#include "data/val-type.h"
 
 #include <gl/xalloc.h>
 #include <assert.h>
@@ -44,7 +45,7 @@ struct levene
   /* Width of the categorical variable */
   int gvw ;
 
-  /* The value deviding the the groups. Valid only for dichotomous categorical variable.*/
+  /* The value dividing the groups. Valid only for dichotomous categorical variable.*/
   const union value *cutpoint;
 
 
@@ -223,12 +224,16 @@ levene_calculate (struct levene *nl)
 
   double numerator = 0.0;
   double nn = 0.0;
-  if ( nl->pass == 3 )
-    {
-      nl->pass = 4;
-    }
 
-  assert (nl->pass == 4);
+  /* The Levene calculation requires three passes.
+     Normally this should have been done prior to calling this function.
+     However, in abnormal circumstances (eg. the dataset is empty) there
+     will have been no passes.
+   */
+  assert (nl->pass == 0 || nl->pass == 3);
+
+  if ( nl->pass == 0 )
+    return SYSMIS;
 
   nl->denominator *= hmap_count (&nl->hmap) - 1;