int CreateTridi(Epetra_CrsMatrix& A)
{
Epetra_Map Map = A.RowMap();
int NumMyElements = Map.NumMyElements();
int NumGlobalElements = Map.NumGlobalElements();
int * MyGlobalElements = new int[NumMyElements];
Map.MyGlobalElements(MyGlobalElements);
// Add rows one-at-a-time
// Need some vectors to help
// Off diagonal Values will always be -1
double *Values = new double[3];
int *Indices = new int[3];
int NumEntries;
for (int i=0; i<NumMyElements; i++)
{
if (MyGlobalElements[i]==0)
{
Indices[0] = 0;
Indices[1] = 1;
Values[0] = 2.0;
Values[1] = -1.0;
NumEntries = 2;
}
else if (MyGlobalElements[i] == NumGlobalElements-1)
{
Indices[0] = NumGlobalElements-1;
Indices[1] = NumGlobalElements-2;
Values[0] = 2.0;
Values[1] = -1.0;
NumEntries = 2;
}
else
{
Indices[0] = MyGlobalElements[i]-1;
Indices[1] = MyGlobalElements[i];
Indices[2] = MyGlobalElements[i]+1;
Values[0] = -1.0;
Values[1] = 2.0;
Values[2] = -1.0;
NumEntries = 3;
}
assert(A.InsertGlobalValues(MyGlobalElements[i], NumEntries, Values, Indices)==0);
// Put in the diagonal entry
// assert(A.InsertGlobalValues(MyGlobalElements[i], 1, &two, &MyGlobalElements[i])==0);
}
// Finish up
assert(A.FillComplete()==0);
delete[] MyGlobalElements;
delete[] Values;
delete[] Indices;
return 0;
}
