* Definition of expression pairs (building blocks of expairseq). */
/*
- * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include "ex.h"
#include "numeric.h"
+#include "print.h"
-#ifndef NO_NAMESPACE_GINAC
namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
/** A pair of expressions.
- * This similar to, but slightly extended STL's pair<> but we need to account
- * for methods like .compare() */
+ * This is similar to STL's pair<>. It is slightly extended since we need to
+ * account for methods like .compare(). Also, since this is meant for use by
+ * class expairseq it must satisfy the invariance that the member coeff must
+ * be of type numeric. */
class expair
{
public:
- expair() {}
- ~expair() {}
-
- expair(const expair & other) : rest(other.rest), coeff(other.coeff)
- {
- GINAC_ASSERT(is_ex_exactly_of_type(coeff,numeric));
- }
-
- const expair & operator=(const expair & other)
- {
- if (this != &other) {
- rest=other.rest;
- coeff=other.coeff;
- }
- return *this;
- }
+ expair() : rest(0), coeff(1) { }
+ /** Construct an expair from two ex. */
expair(const ex & r, const ex & c) : rest(r), coeff(c)
{
- GINAC_ASSERT(is_ex_exactly_of_type(coeff,numeric));
+ GINAC_ASSERT(is_exactly_a<numeric>(coeff));
}
- bool is_numeric_with_coeff_1(void) const
- {
- GINAC_ASSERT(is_ex_exactly_of_type(coeff,numeric));
- return is_ex_exactly_of_type(rest,numeric)
- && (coeff.is_equal(ex(1)));
- }
-
+ /** Member-wise check for canonical ordering equality. */
bool is_equal(const expair & other) const
{
return (rest.is_equal(other.rest) && coeff.is_equal(other.coeff));
}
-
+
+ /** Member-wise check for canonical ordering lessness. */
bool is_less(const expair & other) const
{
- return (rest.compare(other.rest)<0)
- || (!(other.rest.compare(rest)<0) && (coeff.compare(other.coeff)<0));
+ int restcmp = rest.compare(other.rest);
+ return ((restcmp<0) ||
+ (!(restcmp>0) && (coeff.compare(other.coeff)<0)));
}
-
+
+ /** Member-wise check for canonical ordering. */
int compare(const expair & other) const
{
- int cmpval=rest.compare(other.rest);
- if (cmpval!=0) return cmpval;
- cmpval=coeff.compare(other.coeff);
- return cmpval;
- }
-
- bool is_less_old2(const expair & other) const
- {
- /*
- bool this_numeric_with_coeff_1=is_numeric_with_coeff_1();
- bool other_numeric_with_coeff_1=other.is_numeric_with_coeff_1();
- if (this_numeric_with_coeff_1) {
- if (other_numeric_with_coeff_1) {
- // both have coeff 1: compare rests
- return rest.compare(other.rest)<0;
- }
- // only this has coeff 1: >
- return false;
- } else if (other_numeric_with_coeff_1) {
- // only other has coeff 1: <
- return true;
- }
- return (rest.compare(other.rest)<0)
- || (!(other.rest.compare(rest)<0) && (coeff.compare(other.coeff)<0));
- */
- if (is_ex_exactly_of_type(rest,numeric) &&
- is_ex_exactly_of_type(other.rest,numeric)) {
- if (coeff.is_equal(ex(1))) {
- if ((other.coeff).is_equal(ex(1))) {
- // both have coeff 1: compare rests
- return rest.compare(other.rest)<0;
- }
- // only this has coeff 1: >
- return false;
- } else if ((other.coeff).is_equal(ex(1))) {
- // only other has coeff 1: <
- return true;
- }
- // neither has coeff 1: usual compare
- }
- return (rest.compare(other.rest)<0)
- || (!(other.rest.compare(rest)<0) && (coeff.compare(other.coeff)<0));
- }
-
- int compare_old2(const expair & other) const
- {
- if (is_ex_exactly_of_type(rest,numeric) &&
- is_ex_exactly_of_type(other.rest,numeric)) {
- if ((coeff).is_equal(ex(1))) {
- if ((other.coeff).is_equal(ex(1))) {
- // both have coeff 1: compare rests
- return rest.compare(other.rest);
- }
- // only this has coeff 1: >
- return 1;
- } else if ((other.coeff).is_equal(ex(1))) {
- // only other has coeff 1: <
- return -1;
- }
- // neither has coeff 1: usual compare
- }
- /*
- bool this_numeric_with_coeff_1=is_numeric_with_coeff_1();
- bool other_numeric_with_coeff_1=other.is_numeric_with_coeff_1();
- if (this_numeric_with_coeff_1) {
- if (other_numeric_with_coeff_1) {
- // both have coeff 1: compare rests
- return rest.compare(other.rest);
- }
- // only this has coeff 1: >
- return 1;
- } else if (other_numeric_with_coeff_1) {
- // only other has coeff 1: <
- return -1;
- // neither has coeff 1: usual compare
- }
- */
- int cmpval=rest.compare(other.rest);
- if (cmpval!=0) return cmpval;
- return coeff.compare(other.coeff);
+ int restcmp = rest.compare(other.rest);
+ if (restcmp!=0)
+ return restcmp;
+ else
+ return coeff.compare(other.coeff);
}
-
- bool is_less_old(const expair & other) const
- {
- return (rest.compare(other.rest)<0)
- || (!(other.rest.compare(rest)<0) && (coeff.compare(other.coeff)<0));
- }
- int compare_old(const expair & other) const
+
+ void print(std::ostream & os) const;
+
+ /** True if this is of the form (numeric,ex(1)). */
+ bool is_canonical_numeric() const
{
- int cmpval=rest.compare(other.rest);
- if (cmpval!=0) return cmpval;
- cmpval=coeff.compare(other.coeff);
- return cmpval;
+ GINAC_ASSERT(is_exactly_a<numeric>(coeff));
+ return (is_exactly_a<numeric>(rest) && (coeff.is_equal(1)));
}
- void printraw(std::ostream & os) const
+ /** Swap contents with other expair. */
+ void swap(expair & other)
{
- os << "expair(";
- rest.printraw(os);
- os << ",";
- coeff.printraw(os);
- os << ")";
+ rest.swap(other.rest);
+ coeff.swap(other.coeff);
}
+
+ ex rest; ///< first member of pair, an arbitrary expression
+ ex coeff; ///< second member of pair, must be numeric
+};
- ex rest;
- ex coeff;
+/** Function object for insertion into third argument of STL's sort() etc. */
+struct expair_is_less : public std::binary_function<expair, expair, bool> {
+ bool operator()(const expair &lh, const expair &rh) const { return lh.is_less(rh); }
};
-class expair_is_less
-{
-public:
- bool operator()(const expair & lh, const expair & rh) const
- {
- return lh.is_less(rh);
- }
+/** Function object not caring about the numerical coefficients for insertion
+ * into third argument of STL's sort(). Note that this does not define a
+ * strict weak ordering since for any symbol x we have neither 3*x<2*x or
+ * 2*x<3*x. Handle with care! */
+struct expair_rest_is_less : public std::binary_function<expair, expair, bool> {
+ bool operator()(const expair &lh, const expair &rh) const { return (lh.rest.compare(rh.rest)<0); }
};
-class expair_is_less_old
-{
-public:
- bool operator()(const expair & lh, const expair & rh) const
- {
- return lh.is_less_old(rh);
- }
+struct expair_swap : public std::binary_function<expair, expair, void> {
+ void operator()(expair &lh, expair &rh) const { lh.swap(rh); }
};
-#ifndef NO_NAMESPACE_GINAC
+inline void swap(expair & e1, expair & e2)
+{ e1.swap(e2); }
+
+// This makes STL algorithms use the more efficient swap operation for ex objects
+inline void iter_swap(std::vector<expair>::iterator i1, std::vector<expair>::iterator i2)
+{ i1->swap(*i2); }
+
} // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC
#endif // ndef __GINAC_EXPAIR_H__
git://www.ginac.de / ginac.git / blobdiff