# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1296241559 18000
# Node ID 52f6f2989fcd2dce5b38fb8cc991fa003ef34660
# Parent  3d38b4916cbf8a9652ddc14870c8fe59e6cc909c
don't let uninitialized values escape from DNEUPD

diff --git a/liboctave/ChangeLog b/liboctave/ChangeLog
--- a/liboctave/ChangeLog
+++ b/liboctave/ChangeLog
@@ -1,3 +1,9 @@
+2011-01-28  John W. Eaton  <jwe@octave.org>
+
+	* eigs-base.cc (EigsRealNonSymmetricFunc,
+	EigsRealNonSymmetricMatrix, EigsRealNonSymmetricMatrixShift):
+	Initialize eig_vec2 to 0 before calling dneupd.
+
 2011-01-28  John W. Eaton  <jwe@octave.org>
 
 	* eigs-base.cc: Assume we have ARPACK.
diff --git a/liboctave/eigs-base.cc b/liboctave/eigs-base.cc
--- a/liboctave/eigs-base.cc
+++ b/liboctave/eigs-base.cc
@@ -1924,7 +1924,14 @@
   Array<octave_idx_type> s (dim_vector (p, 1));
   octave_idx_type *sel = s.fortran_vec ();
 
-  Matrix eig_vec2 (n, k + 1);
+  // FIXME -- initialize eig_vec2 to zero; apparently dneupd can skip
+  // the assignment to elements of Z that represent imaginary parts.
+  // Found with valgrind and
+  //
+  //   A = [1,0,0,-1;0,1,0,0;0,0,1,0;0,0,2,1];
+  //   [vecs, vals, f] = eigs (A, 1)
+
+  Matrix eig_vec2 (n, k + 1, 0.0);
   double *z = eig_vec2.fortran_vec ();
 
   OCTAVE_LOCAL_BUFFER (double, dr, k + 1);
@@ -2303,7 +2310,14 @@
   Array<octave_idx_type> s (dim_vector (p, 1));
   octave_idx_type *sel = s.fortran_vec ();
 
-  Matrix eig_vec2 (n, k + 1);
+  // FIXME -- initialize eig_vec2 to zero; apparently dneupd can skip
+  // the assignment to elements of Z that represent imaginary parts.
+  // Found with valgrind and
+  //
+  //   A = [1,0,0,-1;0,1,0,0;0,0,1,0;0,0,2,1];
+  //   [vecs, vals, f] = eigs (A, 1)
+
+  Matrix eig_vec2 (n, k + 1, 0.0);
   double *z = eig_vec2.fortran_vec ();
 
   OCTAVE_LOCAL_BUFFER (double, dr, k + 1);
@@ -2608,7 +2622,14 @@
   Array<octave_idx_type> s (dim_vector (p, 1));
   octave_idx_type *sel = s.fortran_vec ();
 
-  Matrix eig_vec2 (n, k + 1);
+  // FIXME -- initialize eig_vec2 to zero; apparently dneupd can skip
+  // the assignment to elements of Z that represent imaginary parts.
+  // Found with valgrind and
+  //
+  //   A = [1,0,0,-1;0,1,0,0;0,0,1,0;0,0,2,1];
+  //   [vecs, vals, f] = eigs (A, 1)
+
+  Matrix eig_vec2 (n, k + 1, 0.0);
   double *z = eig_vec2.fortran_vec ();
 
   OCTAVE_LOCAL_BUFFER (double, dr, k + 1);