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/*
ARPACK++ v1.2 2/18/2000
c++ interface to ARPACK code.
MODULE BCompGSh.cc.
Example program that illustrates how to solve a complex
generalized eigenvalue problem in shift and invert mode using
the ARluCompGenEig class.
1) Problem description:
In this example we try to solve A*x = B*x*lambda in shift and
invert mode, where A and B are derived from a finite element
discretization of a 1-dimensional convection-diffusion operator
(d^2u/dx^2) + rho*(du/dx)
on the interval [0,1], with zero boundary conditions, using
piecewise linear elements.
2) Data structure used to represent matrices A and B:
{ndiagL, ndiagU, A}: matrix A data in band format. The columns
of A are stored sequentially in vector A. ndiagL and ndiagU
supply the lower and upper bandwidth of A, respectively.
{ndiagL, ndiagU, B}: matrix B in band format.
3) Library called by this example:
The LAPACK package is called by ARluCompGenEig to solve
some linear systems involving (A-sigma*B).
4) Included header files:
File Contents
----------- ---------------------------------------------
bcmatrxb.h CompMatrixE, a function that generates matrix
A in band format.
bcmatrxc.h CompMatrixF, a function that generates matrix
B in band format.
arbnsmat.h The ARbdNonSymMatrix class definition.
arbgcomp.h The ARluCompGenEig class definition.
lcompsol.h The Solution function.
arcomp.h The "arcomplex" (complex) type definition.
5) ARPACK Authors:
Richard Lehoucq
Kristyn Maschhoff
Danny Sorensen
Chao Yang
Dept. of Computational & Applied Mathematics
Rice University
Houston, Texas
*/
#include "arcomp.h"
#include "bcmatrxb.h"
#include "bcmatrxc.h"
#include "arbnsmat.h"
#include "arbgcomp.h"
#include "lcompsol.h"
int main()
{
// Defining variables;
int n; // Dimension of the problem.
int ndiagL; // Lower bandwidth of A and B.
int ndiagU; // Upper bandwidth of A and B.
arcomplex<double> rho; // Parameter used to define A.
arcomplex<double> *valA, *valB; // pointers to arrays that store
// the elements of A and B.
// Creating complex matrices A and B.
n = 100;
rho = arcomplex<double>(10.0, 0.0);
CompMatrixB(n, rho, ndiagL, ndiagU, valA);
ARbdNonSymMatrix<arcomplex<double>, double> A(n, ndiagL, ndiagU, valA);
CompMatrixC(n, ndiagL, ndiagU, valB);
ARbdNonSymMatrix<arcomplex<double>, double> B(n, ndiagL, ndiagU, valB);
// Defining what we need: the four eigenvectors nearest to sigma.
ARluCompGenEig<double> dprob(4L, A, B, arcomplex<double>(10.0,0.0));
// Finding eigenvalues and eigenvectors.
dprob.FindEigenvectors();
// Printing solution.
Solution(A, B, dprob);
} // main.
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