AGGREGATE's sort is stable.

[pspp-builds.git] / doc / transformation.texi

diff --git a/doc/transformation.texi b/doc/transformation.texi
index 9225ca80009fb325b71206114aff0c12ea2b962c..d94c1366e63621211aad53e990e6246e9e16145f 100644 (file)
--- a/doc/transformation.texi
+++ b/doc/transformation.texi
@@ -103,6 +103,9 @@ format is F5.3.
 @item FIRST(var_name)
 First non-missing value in break group.  The aggregation variable
 receives the complete dictionary information from the source variable.
+The sort performed by AGGREGATE (and by SORT CASES) is stable, so that
+the first case with particular values for the break variables before
+sorting will also be the first case in that break group after sorting.
 
 @item FOUT(var_name, low, high)
 Fraction of values strictly outside the specified range of constants.
@@ -111,6 +114,9 @@ The default format is F5.3.
 @item LAST(var_name)
 Last non-missing value in break group.  The aggregation variable
 receives the complete dictionary information from the source variable.
+The sort performed by AGGREGATE (and by SORT CASES) is stable, so that
+the last case with particular values for the break variables before
+sorting will also be the last case in that break group after sorting.
 
 @item MAX(var_name)
 Maximum value.  The aggregation variable receives the complete