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/*
ARPACK++ v1.2 2/20/2000
c++ interface to ARPACK code.
MODULE DSMatrxB.h
Function template for the one dimensional discrete Laplacian
on the interval [0, 1], with zero Dirichlet boundary conditions.
ARPACK Authors
Richard Lehoucq
Danny Sorensen
Chao Yang
Dept. of Computational & Applied Mathematics
Rice University
Houston, Texas
*/
#ifndef DSMATRXB_H
#define DSMATRXB_H
#include <math.h>
template<class ARFLOAT, class ARINT>
void DenseMatrixB(ARINT n, ARFLOAT* &A, char uplo = 'L')
{
// Defining internal variables.
ARINT i, j;
ARFLOAT h, df, dd;
// Defining constants.
h = ARFLOAT(n+1);
dd = 2.0*h;
df = -h;
// Creating matrix A.
A = new ARFLOAT[(n*n+n)/2];
if (uplo == 'L') {
for (i=0, j=0; i<n; j+=(n-(i++))) {
A[j] = dd;
if (i != (n-1)) {
A[j+1] = df;
}
}
}
else { // uplo = "U"
for (i=0, j=0; i<n; j+=(++i)) {
A[j+i] = dd;
if (i != 0) {
A[j+i-1] = df;
}
}
}
} // DenseMatrixB.
#endif // DSMATRXB_H
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