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/*
ARPACK++ v1.0 8/1/1997
c++ interface to ARPACK code.
MODULE UCompReg.cc.
Example program that illustrates how to solve a complex standard
eigenvalue problem in regular mode using the ARluCompStdEig class.
1) Problem description:
In this example we try to solve A*x = x*lambda in regular mode,
where A is obtained from the standard central difference
discretization of the convection-diffusion operator
(Laplacian u) + rho*(du / dx)
on the unit square [0,1]x[0,1] with zero Dirichlet boundary
conditions.
2) Data structure used to represent matrix A:
{nnz, irow, pcol, A}: matrix A data in CSC format.
3) Included header files:
File Contents
----------- ---------------------------------------------
lcmatrxa.h CompMatrixA, a function that generates matrix
A in CSC format.
arunsmat.h The ARumNonSymMatrix class definition.
aruscomp.h The ARluCompStdEig class definition.
lcompsol.h The Solution function.
arcomp.h The "arcomplex" (complex) type definition.
4) ARPACK Authors:
Richard Lehoucq
Kristyn Maschhoff
Danny Sorensen
Chao Yang
Dept. of Computational & Applied Mathematics
Rice University
Houston, Texas
*/
#include "arcomp.h"
#include "aruscomp.h"
#include "arunsmat.h"
#include "lcmatrxa.h"
#include "lcompsol.h"
main()
{
// Defining variables;
int nx;
int n; // Dimension of the problem.
int nnz; // Number of nonzero elements in A.
int* irow; // pointer to an array that stores the row
// indices of the nonzeros in A.
int* pcol; // pointer to an array of pointers to the
// beginning of each column of A in valA.
arcomplex<double>* valA; // pointer to an array that stores the
// nonzero elements of A.
// Creating a complex matrix.
nx = 10;
n = nx*nx;
CompMatrixA(nx, nnz, valA, irow, pcol);
ARumNonSymMatrix<arcomplex<double> > A(n, nnz, valA, irow, pcol);
// Defining what we need: the four eigenvectors of A with largest magnitude.
ARluCompStdEig<double> dprob(4L, A);
// Finding eigenvalues and eigenvectors.
dprob.FindEigenvectors();
// Printing solution.
Solution(A, dprob);
} // main
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