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/*
ARPACK++ v1.0 8/1/1997
c++ interface to ARPACK code.
MODULE UCompGSh.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:
{nnzA, irowA, pcolA, valA}: matrix A data in CSC format.
{nnzA, irowA, pcolA, valA}: matrix B data in CSC format.
3) Library called by this example:
The UMFPACK package is called by ARluCompGenEig to solve
some linear systems involving (A-sigma*B).
4) Included header files:
File Contents
----------- ---------------------------------------------
lcmatrxe.h CompMatrixE, a function that generates matrix
A in CSC format.
lcmatrxf.h CompMatrixF, a function that generates matrix
B in CSC format.
arunsmat.h The ARumNonSymMatrix class definition.
arugcomp.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 "lcmatrxe.h"
#include "lcmatrxf.h"
#include "arunsmat.h"
#include "arugcomp.h"
#include "lcompsol.h"
main()
{
// Defining variables;
int n; // Dimension of the problem.
int nnza, nnzb; // Number of nonzero elements in A and B.
int *irowa, *irowb; // pointers to arrays that store the row
// indices of the nonzeros in A and B.
int *pcola, *pcolb; // pointers to arrays of pointers to the
// beginning of each column of A and B in
// valA and ValB.
arcomplex<double> rho; // parameter used in CompMatrixE.
arcomplex<double> *valA, *valB; // pointers to arrays that store the
// nonzero elements of A and B.
// Creating complex matrices A and B.
n = 100;
rho = arcomplex<double>(10.0, 0.0);
CompMatrixE(n, rho, nnza, valA, irowa, pcola);
ARumNonSymMatrix<arcomplex<double> > A(n, nnza, valA, irowa, pcola);
CompMatrixF(n, nnzb, valB, irowb, pcolb);
ARumNonSymMatrix<arcomplex<double> > B(n, nnzb, valB, irowb, pcolb);
// Defining what we need: the four eigenvectors nearest to sigma.
ARluCompGenEig<double> dprob(4L, A, B, arcomplex<double>(1.0,0.0));
// Finding eigenvalues and eigenvectors.
dprob.FindEigenvectors();
// Printing solution.
Solution(A, B, dprob);
} // main.
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