/* $Header: /var/lib/cvs/dynare_cpp/sylv/cc/SylvesterSolver.h,v 1.1.1.1 2004/06/04 13:00:54 kamenik Exp $ */

/* Tag $Name:  $ */

#ifndef SYLVESTER_SOLVER_H
#define SYLVESTER_SOLVER_H

#include "KronVector.h"
#include "QuasiTriangular.h"
#include "QuasiTriangularZero.h"
#include "SimilarityDecomp.h"
#include "SylvParams.h"
#include "SchurDecomp.h"

class SylvesterSolver {
protected:
	const QuasiTriangular* const matrixK;
	const QuasiTriangular* const matrixF;
private:
	/* return true when it is more efficient to use QuasiTriangular
	 * than QuasiTriangularZero */
	static bool zeroPad(const SchurDecompZero& kdecomp) {
		return ((kdecomp.getZeroCols()*3 < kdecomp.getDim()*2) ||
				(kdecomp.getZeroCols() < 10));
	}
public:
	SylvesterSolver(const QuasiTriangular& k, const QuasiTriangular& f)
		: matrixK(new QuasiTriangular(k)),
		  matrixF(new QuasiTriangular(f))
		{}
	SylvesterSolver(const SchurDecompZero& kdecomp, const SchurDecomp& fdecomp)
		: matrixK((zeroPad(kdecomp)) ?
				  new QuasiTriangular(kdecomp) : new QuasiTriangularZero(kdecomp)),
		  matrixF(new QuasiTriangular(fdecomp))
		{}
	SylvesterSolver(const SchurDecompZero& kdecomp, const SimilarityDecomp& fdecomp)
		: matrixK((zeroPad(kdecomp)) ?
				  new QuasiTriangular(kdecomp) : new QuasiTriangularZero(kdecomp)),
		  matrixF(new BlockDiagonal(fdecomp.getB()))
		{}
	virtual ~SylvesterSolver()
		{delete matrixK; delete matrixF;}
	virtual void solve(SylvParams& pars, KronVector& x) const = 0;
};

#endif /* SYLVESTER_SOLVER_H */


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