From: Denis Davydov <davydden@gmail.com>
Date: Fri, 15 Jan 2016 08:23:34 +0000 (+0100)
Subject: make sure vectors passed to EPSSetInitialSpace() are nonzero
X-Git-Tag: v8.4.0-rc2~91^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F2064%2Fhead;p=dealii.git

make sure vectors passed to EPSSetInitialSpace() are nonzero
---

diff --git a/include/deal.II/lac/slepc_solver.h b/include/deal.II/lac/slepc_solver.h
index ecb5cbf329..47c46eaa8e 100644
--- a/include/deal.II/lac/slepc_solver.h
+++ b/include/deal.II/lac/slepc_solver.h
@@ -791,6 +791,8 @@ namespace SLEPcWrappers
 
     for (unsigned int i = 0; i < this_initial_space.size(); i++)
       {
+        Assert(this_initial_space[i].l2_norm()>0.0,
+               ExcMessage("Initial vectors should be nonzero."));
         vecs[i] = this_initial_space[i];
       }
 
diff --git a/source/lac/slepc_solver.cc b/source/lac/slepc_solver.cc
index 1a1d9ab707..d6495ac469 100644
--- a/source/lac/slepc_solver.cc
+++ b/source/lac/slepc_solver.cc
@@ -100,6 +100,9 @@ namespace SLEPcWrappers
   void
   SolverBase::set_initial_vector (const PETScWrappers::VectorBase &this_initial_vector)
   {
+    Assert(this_initial_vector.l2_norm()>0.0,
+           ExcMessage("Initial vector should be nonzero."));
+
     int ierr;
     Vec vec = this_initial_vector;
 #if DEAL_II_PETSC_VERSION_LT(3,1,0)