1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/*
ARPACK++ v1.2 2/20/2000
c++ interface to ARPACK code.
MODULE LNMatrxE.h
Function template that generates a nonsymmetric
tridiagonal matrix with 2 on the main diagonal,
3 on the superdiagonal and -2 on the subdiagonal.
ARPACK Authors
Richard Lehoucq
Danny Sorensen
Chao Yang
Dept. of Computational & Applied Mathematics
Rice University
Houston, Texas
*/
#ifndef LNMATRXE_H
#define LNMATRXE_H
template<class ARFLOAT, class ARINT>
void NonSymMatrixE(ARINT n, ARINT& nnz, ARFLOAT* &A, ARINT* &irow,
ARINT* &pcol)
{
ARINT i, j;
// Defining constants.
const ARFLOAT three = 3.0;
const ARFLOAT two = 2.0;
// Defining the number of nonzero matrix elements.
nnz = 3*n-2;
// Creating output vectors.
A = new ARFLOAT[nnz];
irow = new ARINT[nnz];
pcol = new ARINT[n+1];
// Filling A, irow and pcol.
pcol[0] = 0;
j = 0;
for (i=0; i!=n; i++) {
if (i != 0) {
irow[j] = i-1;
A[j++] = three;
}
irow[j] = i;
A[j++] = two;
if (i != (n-1)) {
irow[j] = i+1;
A[j++] = -two;
}
pcol[i+1] = j;
}
} // NonSymMatrixE.
#endif // LNMATRXE_H
|
