diff --git a/preprocessor/DynamicModel.cc b/preprocessor/DynamicModel.cc
index 5acdf8718..4df16e6c8 100644
--- a/preprocessor/DynamicModel.cc
+++ b/preprocessor/DynamicModel.cc
@@ -2788,11 +2788,12 @@ DynamicModel::writeParamsDerivativesFile(const string &basename) const
   paramsDerivsFile << "if nargout >= 3" << endl;
 
   // Write parameter second derivatives (only if nargout >= 3)
-  paramsDerivsFile << "rpp = zeros(" << equation_number() << ", " << symbol_table.param_nbr() << ", "
-                   << symbol_table.param_nbr() << ");" << endl;
+  paramsDerivsFile << "rpp = zeros(" << residuals_params_second_derivatives.size()
+                   << ",4);" << endl;
 
+  int i = 1;
   for (second_derivatives_type::const_iterator it = residuals_params_second_derivatives.begin();
-       it != residuals_params_second_derivatives.end(); it++)
+       it != residuals_params_second_derivatives.end(); ++it, i++)
     {
       int eq = it->first.first;
       int param1 = it->first.second.first;
@@ -2802,17 +2803,21 @@ DynamicModel::writeParamsDerivativesFile(const string &basename) const
       int param1_col = symbol_table.getTypeSpecificID(getSymbIDByDerivID(param1)) + 1;
       int param2_col = symbol_table.getTypeSpecificID(getSymbIDByDerivID(param2)) + 1;
 
-      paramsDerivsFile << "rpp(" << eq+1 << ", " << param1_col << ", " << param2_col << ") = ";
+      paramsDerivsFile << "rpp(" << i << ",1)=" << eq+1 << ";" << endl
+                       << "rpp(" << i << ",2)=" << param1_col << ";" << endl
+                       << "rpp(" << i << ",3)=" << param2_col << ";" << endl
+                       << "rpp(" << i << ",4)=";
       d2->writeOutput(paramsDerivsFile, oMatlabDynamicModel, params_derivs_temporary_terms);
       paramsDerivsFile << ";" << endl;
     }
 
   // Write jacobian second derivatives  (only if nargout >= 3)
-  paramsDerivsFile << "gpp = zeros(" << equation_number() << ", " << dynJacobianColsNbr << ", "
-                   << symbol_table.param_nbr() << ", " << symbol_table.param_nbr() << ");" << endl;
+  paramsDerivsFile << "gpp = zeros(" << jacobian_params_second_derivatives.size()
+                   << ",5);" << endl;
 
+  i = 1;
   for (third_derivatives_type::const_iterator it = jacobian_params_second_derivatives.begin();
-       it != jacobian_params_second_derivatives.end(); it++)
+       it != jacobian_params_second_derivatives.end(); ++it, i++)
     {
       int eq = it->first.first;
       int var = it->first.second.first;
@@ -2824,7 +2829,11 @@ DynamicModel::writeParamsDerivativesFile(const string &basename) const
       int param1_col = symbol_table.getTypeSpecificID(getSymbIDByDerivID(param1)) + 1;
       int param2_col = symbol_table.getTypeSpecificID(getSymbIDByDerivID(param2)) + 1;
 
-      paramsDerivsFile << "gpp(" << eq+1 << ", " << var_col << ", " << param1_col << ", " << param2_col << ") = ";
+      paramsDerivsFile << "gpp(" << i << ",1)=" << eq+1 << ";" << endl
+                       << "gpp(" << i << ",2)=" << var_col << ";" << endl
+                       << "gpp(" << i << ",3)=" << param1_col << ";" << endl
+                       << "gpp(" << i << ",4)=" << param2_col << ";" << endl
+                       << "gpp(" << i << ",5)=";
       d2->writeOutput(paramsDerivsFile, oMatlabDynamicModel, params_derivs_temporary_terms);
       paramsDerivsFile << ";" << endl;
     }
@@ -2834,11 +2843,11 @@ DynamicModel::writeParamsDerivativesFile(const string &basename) const
                    << "if nargout >= 5" << endl;
 
   // Write hessian derivatives (only if nargout >= 5)
-  paramsDerivsFile << "hp = zeros(" << equation_number() << ", " << dynJacobianColsNbr << ", "
-                   << dynJacobianColsNbr << ", " << symbol_table.param_nbr() << ");" << endl;
+  paramsDerivsFile << "hp = zeros(" << hessian_params_derivatives.size() << ",5);" << endl;
 
+  i = 1;
   for (third_derivatives_type::const_iterator it = hessian_params_derivatives.begin();
-       it != hessian_params_derivatives.end(); it++)
+       it != hessian_params_derivatives.end(); ++it, i++)
     {
       int eq = it->first.first;
       int var1 = it->first.second.first;
@@ -2850,7 +2859,11 @@ DynamicModel::writeParamsDerivativesFile(const string &basename) const
       int var2_col = getDynJacobianCol(var2) + 1;
       int param_col = symbol_table.getTypeSpecificID(getSymbIDByDerivID(param)) + 1;
 
-      paramsDerivsFile << "hp(" << eq+1 << ", " << var1_col << ", " << var2_col << ", " << param_col << ") = ";
+      paramsDerivsFile << "hp(" << i << ",1)=" << eq+1 << ";" << endl
+                       << "hp(" << i << ",2)=" << var1_col << ";" << endl
+                       << "hp(" << i << ",3)=" << var2_col << ";" << endl
+                       << "hp(" << i << ",4)=" << param_col << ";" << endl
+                       << "hp(" << i << ",5)=";
       d2->writeOutput(paramsDerivsFile, oMatlabDynamicModel, params_derivs_temporary_terms);
       paramsDerivsFile << ";" << endl;
     }