affine_func.h

由matlab开发的hybrid系统的描述语言

/*
	HYSDEL
	Copyright (C) 1999-2002  Fabio D. Torrisi

	This file is part of HYSDEL.
    
	HYSDEL is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public
	License as published by the Free Software Foundation; either
	version 2 of the License, or (at your option) any later version.

	HYSDEL is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	CONTACT INFORMATION
	===================
	Fabio D. Torrisi
	ETH Zentrum
	Physikstrasse. 3 ETL,
	CH-8032 Zurich
	Switzerland
	mailto:[e-mail] (preferred)
*/

#ifndef D_AFFINE_FUNC
#define D_AFFINE_FUNC
#ifndef STD_NS
#define STD_NS
using namespace std;
#endif
#include <list>
#include <string>

class Expr;
class Var_symbol;
class Affine_addend;
class Globals;

/** representation of an Expression as an affine function. */
class Affine_func {
public:
	/** create an empty (i.e. =0) affine function */
	Affine_func(const Globals * glob);

	/** create an affine function with just the constant part c */
	Affine_func(Expr * c, const Globals * glob);

	/** create an affine function with a single variable var and set
	 * its coefficient to one */
	Affine_func(const Var_symbol * var, const Globals * glob);

	~Affine_func();

	Affine_func *clone() const;

	const list < Affine_addend * > * get_addends() const
		{ return & addends; }

	/** addition of two affine functions */
	void add(Affine_func * add);

	/** subtraction of two affine functions */
	void sub(Affine_func * sub);

	/* multiply the affine function with a constant */
	void mult_const(Expr * c);

	/* divide the affine function by a constant */
	void div_const(Expr * c);

	/* negate the affine function */
	void neg();

	/* simplify each coefficient as far as possible */
	void simplify();

	/* output in human readable form, for debug only */
	string to_string() const;


	/** find the Affine_addend in addends whose variable is var
	 * return NULL if no such addend exists */
	const Affine_addend * find_addend(const Var_symbol * var) const;

	/** remove the constant part and return it. Return NULL if the
	 * function is linear. */
	Affine_addend * remove_const();

	/** convert back to Expr */
	Expr * to_expr() const;

private:
	Affine_addend * find_addend_nonconst(const Var_symbol * var);

	const Globals * globals;

	/** contains all addends, also the constant part. A variable
	 * must not appear more than once in this list. */
	list < Affine_addend * > addends;
	typedef list < Affine_addend * >::iterator addends_iter;
	typedef list < Affine_addend * >::const_iterator const_addends_iter;
};
#endif //D_AFFINE_FUNC