# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1291746260 18000
# Node ID d7ea780b036f30610a6cbf96358e9d43c919be7b
# Parent  2da532d0f41ce2a95a1f121967ed0358511c1f35
repmat: handle special case of replicating scalar using index vector containing zeros

diff --git a/scripts/ChangeLog b/scripts/ChangeLog
--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,3 +1,8 @@
+2010-12-07  John W. Eaton  <jwe@octave.org>
+
+	* general/repmat.m: Handle special case of replicating scalar
+	using an index vector containing zeros.  Bug #31775.
+
 2010-12-06  Rik  <octave@nomad.inbox5.com>
 
 	* plot/plot.m: Eliminate present tense in first sentence of docstring.
diff --git a/scripts/general/repmat.m b/scripts/general/repmat.m
--- a/scripts/general/repmat.m
+++ b/scripts/general/repmat.m
@@ -61,8 +61,12 @@
 
   if (numel (a) == 1)
     ## optimize the scalar fill case.
-    x(1:prod (idx)) = a;
-    x = reshape (x, idx);
+    if (any (idx == 0))
+      x = resize (a, idx);
+    else
+      x(1:prod (idx)) = a;
+      x = reshape (x, idx);
+    endif
   elseif (ndims (a) == 2 && length (idx) < 3)
     if (issparse (a))
       x = kron (ones (idx), a);
@@ -136,3 +140,21 @@
 %!assert (size (repmat (".", -1, 1)), [0, 1]);
 %!assert (size (repmat (".", 1, -1)), [1, 0]);
 %!error (size (repmat (".", -1, -1)));
+
+%!assert (size (repmat (1, [1, 0])), [1, 0]);
+%!assert (size (repmat (1, [5, 0])), [5, 0]);
+%!assert (size (repmat (1, [0, 1])), [0, 1]);
+%!assert (size (repmat (1, [0, 5])), [0, 5]);
+
+%!shared x
+%! x = struct ("a", [], "b", []);
+%!assert (size (repmat (x, [1, 0])), [1, 0]);
+%!assert (size (repmat (x, [5, 0])), [5, 0]);
+%!assert (size (repmat (x, [0, 1])), [0, 1]);
+%!assert (size (repmat (x, [0, 5])), [0, 5]);
+
+%!assert (size (repmat ({1}, [1, 0])), [1, 0]);
+%!assert (size (repmat ({1}, [5, 0])), [5, 0]);
+%!assert (size (repmat ({1}, [0, 1])), [0, 1]);
+%!assert (size (repmat ({1}, [0, 5])), [0, 5]);
+