diff --git a/matlab/dr1.m b/matlab/dr1.m
index 1dd84cede..d886b768b 100644
--- a/matlab/dr1.m
+++ b/matlab/dr1.m
@@ -543,7 +543,6 @@ function [dr,info,M_,options_,oo_] = dr1(dr,task,M_,options_,oo_)
     zx=[zx; zeros(M_.exo_nbr,np);zeros(M_.exo_det_nbr,np)];
     zu=[zu; eye(M_.exo_nbr);zeros(M_.exo_det_nbr,M_.exo_nbr)];
     [nrzx,nczx] = size(zx);
-    hessian = sparse(hessian);
     rhs = -sparse_hessian_times_B_kronecker_C(hessian,zx);
     
     %lhs
diff --git a/preprocessor/ModelTree.cc b/preprocessor/ModelTree.cc
index 026658793..7a1cb8969 100644
--- a/preprocessor/ModelTree.cc
+++ b/preprocessor/ModelTree.cc
@@ -1657,8 +1657,10 @@ ModelTree::writeDynamicCFile(const string &dynamic_basename) const
                     << "  g2 = NULL;" << endl
                     << " if (nlhs >= 3)" << endl
                     << "  {" << endl
-                    << "     /* Set the output pointer to the output matrix g2. */" << endl
-                    << "     plhs[2] = mxCreateDoubleMatrix(" << equations.size() << ", " << variable_table.getDynJacobianColsNbr(computeJacobianExo)*variable_table.getDynJacobianColsNbr(computeJacobianExo) << ", mxREAL);" << endl
+                    << "     /* Set the output pointer to the output matrix g2. */" << endl;
+  int g2_ncols = variable_table.getDynJacobianColsNbr(computeJacobianExo)*variable_table.getDynJacobianColsNbr(computeJacobianExo);
+  mDynamicModelFile << "     plhs[2] = mxCreateSparse(" << equations.size() << ", " << g2_ncols << ", "
+                    << 5*g2_ncols << ", mxREAL);" << endl
                     << "     /* Create a C pointer to a copy of the output matrix g1. */" << endl
                     << "     g2 = mxGetPr(plhs[2]);" << endl
                     << "  }" << endl