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/*
ARPACK++ v1.2 2/20/2000
c++ interface to ARPACK code.
MODULE DNMatrxC.h
Function template for the mass matrix formed by using piecewise
linear elements on [0, 1].
ARPACK Authors
Richard Lehoucq
Danny Sorensen
Chao Yang
Dept. of Computational & Applied Mathematics
Rice University
Houston, Texas
*/
#ifndef DNMATRXC_H
#define DNMATRXC_H
template<class ARFLOAT, class ARINT>
void MassMatrix(ARINT n, ARFLOAT* &A)
{
ARINT i, j;
ARFLOAT diag, sub;
// Defining constants.
sub = 1.0/6.0/ARFLOAT(n+1);
diag = 4.0/6.0/ARFLOAT(n+1);
// Creating output vector A.
A = new ARFLOAT[n*n];
for (i=0; i<n*n; i++) A[i]=0.0;
for (i=0, j=0; i<n; i++, j+=n+1) {
if (i) A[j-1] = sub;
A[j] = diag;
if (n-i-1) A[j+1] = sub;
}
} // MassMatrix.
#endif // DNMATRXC_H
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