* Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
/*
- * GiNaC Copyright (C) 1999 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2015 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
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#include <vector>
-#include <iostream>
-#include <stdexcept>
-
#include "power.h"
#include "expairseq.h"
#include "add.h"
#include "mul.h"
+#include "ncmul.h"
#include "numeric.h"
-#include "relational.h"
+#include "constant.h"
+#include "operators.h"
+#include "inifcns.h" // for log() in power::derivative()
+#include "matrix.h"
+#include "indexed.h"
#include "symbol.h"
-#include "debugmsg.h"
+#include "lst.h"
+#include "archive.h"
+#include "utils.h"
+#include "relational.h"
+#include "compiler.h"
+
+#include <iostream>
+#include <limits>
+#include <stdexcept>
+#include <vector>
+#include <algorithm>
-#ifndef NO_GINAC_NAMESPACE
namespace GiNaC {
-#endif // ndef NO_GINAC_NAMESPACE
-typedef vector<int> intvector;
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(power, basic,
+ print_func<print_dflt>(&power::do_print_dflt).
+ print_func<print_latex>(&power::do_print_latex).
+ print_func<print_csrc>(&power::do_print_csrc).
+ print_func<print_python>(&power::do_print_python).
+ print_func<print_python_repr>(&power::do_print_python_repr).
+ print_func<print_csrc_cl_N>(&power::do_print_csrc_cl_N))
//////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default constructor
//////////
-// public
+power::power() { }
-power::power() : basic(TINFO_power)
+//////////
+// other constructors
+//////////
+
+// all inlined
+
+//////////
+// archiving
+//////////
+
+void power::read_archive(const archive_node &n, lst &sym_lst)
{
- debugmsg("power default constructor",LOGLEVEL_CONSTRUCT);
+ inherited::read_archive(n, sym_lst);
+ n.find_ex("basis", basis, sym_lst);
+ n.find_ex("exponent", exponent, sym_lst);
}
-power::~power()
+void power::archive(archive_node &n) const
{
- debugmsg("power destructor",LOGLEVEL_DESTRUCT);
- destroy(0);
+ inherited::archive(n);
+ n.add_ex("basis", basis);
+ n.add_ex("exponent", exponent);
}
-power::power(power const & other)
+//////////
+// functions overriding virtual functions from base classes
+//////////
+
+// public
+
+void power::print_power(const print_context & c, const char *powersymbol, const char *openbrace, const char *closebrace, unsigned level) const
{
- debugmsg("power copy constructor",LOGLEVEL_CONSTRUCT);
- copy(other);
+ // Ordinary output of powers using '^' or '**'
+ if (precedence() <= level)
+ c.s << openbrace << '(';
+ basis.print(c, precedence());
+ c.s << powersymbol;
+ c.s << openbrace;
+ exponent.print(c, precedence());
+ c.s << closebrace;
+ if (precedence() <= level)
+ c.s << ')' << closebrace;
}
-power const & power::operator=(power const & other)
+void power::do_print_dflt(const print_dflt & c, unsigned level) const
{
- debugmsg("power operator=",LOGLEVEL_ASSIGNMENT);
- if (this != &other) {
- destroy(1);
- copy(other);
- }
- return *this;
-}
+ if (exponent.is_equal(_ex1_2)) {
-// protected
+ // Square roots are printed in a special way
+ c.s << "sqrt(";
+ basis.print(c);
+ c.s << ')';
-void power::copy(power const & other)
-{
- basic::copy(other);
- basis=other.basis;
- exponent=other.exponent;
+ } else
+ print_power(c, "^", "", "", level);
}
-void power::destroy(bool call_parent)
+void power::do_print_latex(const print_latex & c, unsigned level) const
{
- if (call_parent) basic::destroy(call_parent);
-}
+ if (is_exactly_a<numeric>(exponent) && ex_to<numeric>(exponent).is_negative()) {
-//////////
-// other constructors
-//////////
+ // Powers with negative numeric exponents are printed as fractions
+ c.s << "\\frac{1}{";
+ power(basis, -exponent).eval().print(c);
+ c.s << '}';
-// public
+ } else if (exponent.is_equal(_ex1_2)) {
+
+ // Square roots are printed in a special way
+ c.s << "\\sqrt{";
+ basis.print(c);
+ c.s << '}';
+
+ } else
+ print_power(c, "^", "{", "}", level);
+}
-power::power(ex const & lh, ex const & rh) : basic(TINFO_power), basis(lh), exponent(rh)
+static void print_sym_pow(const print_context & c, const symbol &x, int exp)
{
- debugmsg("power constructor from ex,ex",LOGLEVEL_CONSTRUCT);
- GINAC_ASSERT(basis.return_type()==return_types::commutative);
+ // Optimal output of integer powers of symbols to aid compiler CSE.
+ // C.f. ISO/IEC 14882:1998, section 1.9 [intro execution], paragraph 15
+ // to learn why such a parenthesation is really necessary.
+ if (exp == 1) {
+ x.print(c);
+ } else if (exp == 2) {
+ x.print(c);
+ c.s << "*";
+ x.print(c);
+ } else if (exp & 1) {
+ x.print(c);
+ c.s << "*";
+ print_sym_pow(c, x, exp-1);
+ } else {
+ c.s << "(";
+ print_sym_pow(c, x, exp >> 1);
+ c.s << ")*(";
+ print_sym_pow(c, x, exp >> 1);
+ c.s << ")";
+ }
}
-power::power(ex const & lh, numeric const & rh) : basic(TINFO_power), basis(lh), exponent(rh)
+void power::do_print_csrc_cl_N(const print_csrc_cl_N& c, unsigned level) const
{
- debugmsg("power constructor from ex,numeric",LOGLEVEL_CONSTRUCT);
- GINAC_ASSERT(basis.return_type()==return_types::commutative);
+ if (exponent.is_equal(_ex_1)) {
+ c.s << "recip(";
+ basis.print(c);
+ c.s << ')';
+ return;
+ }
+ c.s << "expt(";
+ basis.print(c);
+ c.s << ", ";
+ exponent.print(c);
+ c.s << ')';
}
-//////////
-// functions overriding virtual functions from bases classes
-//////////
+void power::do_print_csrc(const print_csrc & c, unsigned level) const
+{
+ // Integer powers of symbols are printed in a special, optimized way
+ if (exponent.info(info_flags::integer) &&
+ (is_a<symbol>(basis) || is_a<constant>(basis))) {
+ int exp = ex_to<numeric>(exponent).to_int();
+ if (exp > 0)
+ c.s << '(';
+ else {
+ exp = -exp;
+ c.s << "1.0/(";
+ }
+ print_sym_pow(c, ex_to<symbol>(basis), exp);
+ c.s << ')';
+
+ // <expr>^-1 is printed as "1.0/<expr>" or with the recip() function of CLN
+ } else if (exponent.is_equal(_ex_1)) {
+ c.s << "1.0/(";
+ basis.print(c);
+ c.s << ')';
+
+ // Otherwise, use the pow() function
+ } else {
+ c.s << "pow(";
+ basis.print(c);
+ c.s << ',';
+ exponent.print(c);
+ c.s << ')';
+ }
+}
-// public
+void power::do_print_python(const print_python & c, unsigned level) const
+{
+ print_power(c, "**", "", "", level);
+}
-basic * power::duplicate() const
+void power::do_print_python_repr(const print_python_repr & c, unsigned level) const
{
- debugmsg("power duplicate",LOGLEVEL_DUPLICATE);
- return new power(*this);
+ c.s << class_name() << '(';
+ basis.print(c);
+ c.s << ',';
+ exponent.print(c);
+ c.s << ')';
}
bool power::info(unsigned inf) const
{
- if (inf==info_flags::polynomial || inf==info_flags::integer_polynomial || inf==info_flags::rational_polynomial) {
- return exponent.info(info_flags::nonnegint);
- } else if (inf==info_flags::rational_function) {
- return exponent.info(info_flags::integer);
- } else {
- return basic::info(inf);
- }
+ switch (inf) {
+ case info_flags::polynomial:
+ case info_flags::integer_polynomial:
+ case info_flags::cinteger_polynomial:
+ case info_flags::rational_polynomial:
+ case info_flags::crational_polynomial:
+ return exponent.info(info_flags::nonnegint) &&
+ basis.info(inf);
+ case info_flags::rational_function:
+ return exponent.info(info_flags::integer) &&
+ basis.info(inf);
+ case info_flags::algebraic:
+ return !exponent.info(info_flags::integer) ||
+ basis.info(inf);
+ case info_flags::expanded:
+ return (flags & status_flags::expanded);
+ case info_flags::positive:
+ return basis.info(info_flags::positive) && exponent.info(info_flags::real);
+ case info_flags::nonnegative:
+ return (basis.info(info_flags::positive) && exponent.info(info_flags::real)) ||
+ (basis.info(info_flags::real) && exponent.info(info_flags::integer) && exponent.info(info_flags::even));
+ case info_flags::has_indices: {
+ if (flags & status_flags::has_indices)
+ return true;
+ else if (flags & status_flags::has_no_indices)
+ return false;
+ else if (basis.info(info_flags::has_indices)) {
+ setflag(status_flags::has_indices);
+ clearflag(status_flags::has_no_indices);
+ return true;
+ } else {
+ clearflag(status_flags::has_indices);
+ setflag(status_flags::has_no_indices);
+ return false;
+ }
+ }
+ }
+ return inherited::info(inf);
}
-int power::nops() const
+size_t power::nops() const
{
- return 2;
+ return 2;
}
-ex & power::let_op(int const i)
+ex power::op(size_t i) const
{
- GINAC_ASSERT(i>=0);
- GINAC_ASSERT(i<2);
+ GINAC_ASSERT(i<2);
- return i==0 ? basis : exponent;
+ return i==0 ? basis : exponent;
}
-int power::degree(symbol const & s) const
+ex power::map(map_function & f) const
{
- if (is_exactly_of_type(*exponent.bp,numeric)) {
- if ((*basis.bp).compare(s)==0)
- return ex_to_numeric(exponent).to_int();
- else
- return basis.degree(s) * ex_to_numeric(exponent).to_int();
- }
- return 0;
+ const ex &mapped_basis = f(basis);
+ const ex &mapped_exponent = f(exponent);
+
+ if (!are_ex_trivially_equal(basis, mapped_basis)
+ || !are_ex_trivially_equal(exponent, mapped_exponent))
+ return (new power(mapped_basis, mapped_exponent))->setflag(status_flags::dynallocated);
+ else
+ return *this;
}
-int power::ldegree(symbol const & s) const
+bool power::is_polynomial(const ex & var) const
{
- if (is_exactly_of_type(*exponent.bp,numeric)) {
- if ((*basis.bp).compare(s)==0)
- return ex_to_numeric(exponent).to_int();
- else
- return basis.ldegree(s) * ex_to_numeric(exponent).to_int();
- }
- return 0;
+ if (basis.is_polynomial(var)) {
+ if (basis.has(var))
+ // basis is non-constant polynomial in var
+ return exponent.info(info_flags::nonnegint);
+ else
+ // basis is constant in var
+ return !exponent.has(var);
+ }
+ // basis is a non-polynomial function of var
+ return false;
}
-ex power::coeff(symbol const & s, int const n) const
+int power::degree(const ex & s) const
{
- if ((*basis.bp).compare(s)!=0) {
- // basis not equal to s
- if (n==0) {
- return *this;
- } else {
- return exZERO();
- }
- } else if (is_exactly_of_type(*exponent.bp,numeric)&&
- (static_cast<numeric const &>(*exponent.bp).compare(numeric(n))==0)) {
- return exONE();
- }
+ if (is_equal(ex_to<basic>(s)))
+ return 1;
+ else if (is_exactly_a<numeric>(exponent) && ex_to<numeric>(exponent).is_integer()) {
+ if (basis.is_equal(s))
+ return ex_to<numeric>(exponent).to_int();
+ else
+ return basis.degree(s) * ex_to<numeric>(exponent).to_int();
+ } else if (basis.has(s))
+ throw(std::runtime_error("power::degree(): undefined degree because of non-integer exponent"));
+ else
+ return 0;
+}
- return exZERO();
+int power::ldegree(const ex & s) const
+{
+ if (is_equal(ex_to<basic>(s)))
+ return 1;
+ else if (is_exactly_a<numeric>(exponent) && ex_to<numeric>(exponent).is_integer()) {
+ if (basis.is_equal(s))
+ return ex_to<numeric>(exponent).to_int();
+ else
+ return basis.ldegree(s) * ex_to<numeric>(exponent).to_int();
+ } else if (basis.has(s))
+ throw(std::runtime_error("power::ldegree(): undefined degree because of non-integer exponent"));
+ else
+ return 0;
}
+ex power::coeff(const ex & s, int n) const
+{
+ if (is_equal(ex_to<basic>(s)))
+ return n==1 ? _ex1 : _ex0;
+ else if (!basis.is_equal(s)) {
+ // basis not equal to s
+ if (n == 0)
+ return *this;
+ else
+ return _ex0;
+ } else {
+ // basis equal to s
+ if (is_exactly_a<numeric>(exponent) && ex_to<numeric>(exponent).is_integer()) {
+ // integer exponent
+ int int_exp = ex_to<numeric>(exponent).to_int();
+ if (n == int_exp)
+ return _ex1;
+ else
+ return _ex0;
+ } else {
+ // non-integer exponents are treated as zero
+ if (n == 0)
+ return *this;
+ else
+ return _ex0;
+ }
+ }
+}
+
+/** Perform automatic term rewriting rules in this class. In the following
+ * x, x1, x2,... stand for a symbolic variables of type ex and c, c1, c2...
+ * stand for such expressions that contain a plain number.
+ * - ^(x,0) -> 1 (also handles ^(0,0))
+ * - ^(x,1) -> x
+ * - ^(0,c) -> 0 or exception (depending on the real part of c)
+ * - ^(1,x) -> 1
+ * - ^(c1,c2) -> *(c1^n,c1^(c2-n)) (so that 0<(c2-n)<1, try to evaluate roots, possibly in numerator and denominator of c1)
+ * - ^(^(x,c1),c2) -> ^(x,c1*c2) if x is positive and c1 is real.
+ * - ^(^(x,c1),c2) -> ^(x,c1*c2) (c2 integer or -1 < c1 <= 1 or (c1=-1 and c2>0), case c1=1 should not happen, see below!)
+ * - ^(*(x,y,z),c) -> *(x^c,y^c,z^c) (if c integer)
+ * - ^(*(x,c1),c2) -> ^(x,c2)*c1^c2 (c1>0)
+ * - ^(*(x,c1),c2) -> ^(-x,c2)*c1^c2 (c1<0)
+ *
+ * @param level cut-off in recursive evaluation */
ex power::eval(int level) const
{
- // simplifications: ^(x,0) -> 1 (0^0 handled here)
- // ^(x,1) -> x
- // ^(0,x) -> 0 (except if x is real and negative, in which case an exception is thrown)
- // ^(1,x) -> 1
- // ^(c1,c2) -> *(c1^n,c1^(c2-n)) (c1, c2 numeric(), 0<(c2-n)<1 except if c1,c2 are rational, but c1^c2 is not)
- // ^(^(x,c1),c2) -> ^(x,c1*c2) (c1, c2 numeric(), c2 integer or -1 < c1 <= 1, case c1=1 should not happen, see below!)
- // ^(*(x,y,z),c1) -> *(x^c1,y^c1,z^c1) (c1 integer)
- // ^(*(x,c1),c2) -> ^(x,c2)*c1^c2 (c1, c2 numeric(), c1>0)
- // ^(*(x,c1),c2) -> ^(-x,c2)*c1^c2 (c1, c2 numeric(), c1<0)
-
- debugmsg("power eval",LOGLEVEL_MEMBER_FUNCTION);
-
- if ((level==1)&&(flags & status_flags::evaluated)) {
- return *this;
- } else if (level == -max_recursion_level) {
- throw(std::runtime_error("max recursion level reached"));
- }
-
- ex const & ebasis = level==1 ? basis : basis.eval(level-1);
- ex const & eexponent = level==1 ? exponent : exponent.eval(level-1);
-
- bool basis_is_numerical=0;
- bool exponent_is_numerical=0;
- numeric * num_basis;
- numeric * num_exponent;
-
- if (is_exactly_of_type(*ebasis.bp,numeric)) {
- basis_is_numerical=1;
- num_basis=static_cast<numeric *>(ebasis.bp);
- }
- if (is_exactly_of_type(*eexponent.bp,numeric)) {
- exponent_is_numerical=1;
- num_exponent=static_cast<numeric *>(eexponent.bp);
- }
-
- // ^(x,0) -> 1 (0^0 also handled here)
- if (eexponent.is_zero())
- return exONE();
-
- // ^(x,1) -> x
- if (eexponent.is_equal(exONE()))
- return ebasis;
-
- // ^(0,x) -> 0 (except if x is real and negative)
- if (ebasis.is_zero()) {
- if (exponent_is_numerical && num_exponent->is_negative()) {
- throw(std::overflow_error("power::eval(): division by zero"));
- } else
- return exZERO();
- }
-
- // ^(1,x) -> 1
- if (ebasis.is_equal(exONE()))
- return exONE();
-
- if (basis_is_numerical && exponent_is_numerical) {
- // ^(c1,c2) -> c1^c2 (c1, c2 numeric(),
- // except if c1,c2 are rational, but c1^c2 is not)
- bool basis_is_rational = num_basis->is_rational();
- bool exponent_is_rational = num_exponent->is_rational();
- numeric res = (*num_basis).power(*num_exponent);
-
- if ((!basis_is_rational || !exponent_is_rational)
- || res.is_rational()) {
- return res;
- }
- GINAC_ASSERT(!num_exponent->is_integer()); // has been handled by now
- // ^(c1,n/m) -> *(c1^q,c1^(n/m-q)), 0<(n/m-h)<1, q integer
- if (basis_is_rational && exponent_is_rational
- && num_exponent->is_real()
- && !num_exponent->is_integer()) {
- numeric r, q, n, m;
- n = num_exponent->numer();
- m = num_exponent->denom();
- q = iquo(n, m, r);
- if (r.is_negative()) {
- r = r.add(m);
- q = q.sub(numONE());
- }
- if (q.is_zero()) // the exponent was in the allowed range 0<(n/m)<1
- return this->hold();
- else {
- epvector res(2);
- res.push_back(expair(ebasis,r.div(m)));
- res.push_back(expair(ex(num_basis->power(q)),exONE()));
- return (new mul(res))->setflag(status_flags::dynallocated | status_flags::evaluated);
- /*return mul(num_basis->power(q),
- power(ex(*num_basis),ex(r.div(m)))).hold();
- */
- /* return (new mul(num_basis->power(q),
- power(*num_basis,r.div(m)).hold()))->setflag(status_flags::dynallocated | status_flags::evaluated);
- */
- }
- }
- }
-
- // ^(^(x,c1),c2) -> ^(x,c1*c2)
- // (c1, c2 numeric(), c2 integer or -1 < c1 <= 1,
- // case c1=1 should not happen, see below!)
- if (exponent_is_numerical && is_ex_exactly_of_type(ebasis,power)) {
- power const & sub_power=ex_to_power(ebasis);
- ex const & sub_basis=sub_power.basis;
- ex const & sub_exponent=sub_power.exponent;
- if (is_ex_exactly_of_type(sub_exponent,numeric)) {
- numeric const & num_sub_exponent=ex_to_numeric(sub_exponent);
- GINAC_ASSERT(num_sub_exponent!=numeric(1));
- if (num_exponent->is_integer() || abs(num_sub_exponent)<1) {
- return power(sub_basis,num_sub_exponent.mul(*num_exponent));
- }
- }
- }
-
- // ^(*(x,y,z),c1) -> *(x^c1,y^c1,z^c1) (c1 integer)
- if (exponent_is_numerical && num_exponent->is_integer() &&
- is_ex_exactly_of_type(ebasis,mul)) {
- return expand_mul(ex_to_mul(ebasis), *num_exponent);
- }
-
- // ^(*(...,x;c1),c2) -> ^(*(...,x;1),c2)*c1^c2 (c1, c2 numeric(), c1>0)
- // ^(*(...,x,c1),c2) -> ^(*(...,x;-1),c2)*(-c1)^c2 (c1, c2 numeric(), c1<0)
- if (exponent_is_numerical && is_ex_exactly_of_type(ebasis,mul)) {
- GINAC_ASSERT(!num_exponent->is_integer()); // should have been handled above
- mul const & mulref=ex_to_mul(ebasis);
- if (!mulref.overall_coeff.is_equal(exONE())) {
- numeric const & num_coeff=ex_to_numeric(mulref.overall_coeff);
- if (num_coeff.is_real()) {
- if (num_coeff.is_positive()>0) {
- mul * mulp=new mul(mulref);
- mulp->overall_coeff=exONE();
- mulp->clearflag(status_flags::evaluated);
- mulp->clearflag(status_flags::hash_calculated);
- return (new mul(power(*mulp,exponent),
- power(num_coeff,*num_exponent)))->
- setflag(status_flags::dynallocated);
- } else {
- GINAC_ASSERT(num_coeff.compare(numZERO())<0);
- if (num_coeff.compare(numMINUSONE())!=0) {
- mul * mulp=new mul(mulref);
- mulp->overall_coeff=exMINUSONE();
- mulp->clearflag(status_flags::evaluated);
- mulp->clearflag(status_flags::hash_calculated);
- return (new mul(power(*mulp,exponent),
- power(abs(num_coeff),*num_exponent)))->
- setflag(status_flags::dynallocated);
- }
- }
- }
- }
- }
-
- if (are_ex_trivially_equal(ebasis,basis) &&
- are_ex_trivially_equal(eexponent,exponent)) {
- return this->hold();
- }
- return (new power(ebasis, eexponent))->setflag(status_flags::dynallocated |
- status_flags::evaluated);
+ if ((level==1) && (flags & status_flags::evaluated))
+ return *this;
+ else if (level == -max_recursion_level)
+ throw(std::runtime_error("max recursion level reached"));
+
+ const ex & ebasis = level==1 ? basis : basis.eval(level-1);
+ const ex & eexponent = level==1 ? exponent : exponent.eval(level-1);
+
+ const numeric *num_basis = NULL;
+ const numeric *num_exponent = NULL;
+
+ if (is_exactly_a<numeric>(ebasis)) {
+ num_basis = &ex_to<numeric>(ebasis);
+ }
+ if (is_exactly_a<numeric>(eexponent)) {
+ num_exponent = &ex_to<numeric>(eexponent);
+ }
+
+ // ^(x,0) -> 1 (0^0 also handled here)
+ if (eexponent.is_zero()) {
+ if (ebasis.is_zero())
+ throw (std::domain_error("power::eval(): pow(0,0) is undefined"));
+ else
+ return _ex1;
+ }
+
+ // ^(x,1) -> x
+ if (eexponent.is_equal(_ex1))
+ return ebasis;
+
+ // ^(0,c1) -> 0 or exception (depending on real value of c1)
+ if ( ebasis.is_zero() && num_exponent ) {
+ if ((num_exponent->real()).is_zero())
+ throw (std::domain_error("power::eval(): pow(0,I) is undefined"));
+ else if ((num_exponent->real()).is_negative())
+ throw (pole_error("power::eval(): division by zero",1));
+ else
+ return _ex0;
+ }
+
+ // ^(1,x) -> 1
+ if (ebasis.is_equal(_ex1))
+ return _ex1;
+
+ // power of a function calculated by separate rules defined for this function
+ if (is_exactly_a<function>(ebasis))
+ return ex_to<function>(ebasis).power(eexponent);
+
+ // Turn (x^c)^d into x^(c*d) in the case that x is positive and c is real.
+ if (is_exactly_a<power>(ebasis) && ebasis.op(0).info(info_flags::positive) && ebasis.op(1).info(info_flags::real))
+ return power(ebasis.op(0), ebasis.op(1) * eexponent);
+
+ if ( num_exponent ) {
+
+ // ^(c1,c2) -> c1^c2 (c1, c2 numeric(),
+ // except if c1,c2 are rational, but c1^c2 is not)
+ if ( num_basis ) {
+ const bool basis_is_crational = num_basis->is_crational();
+ const bool exponent_is_crational = num_exponent->is_crational();
+ if (!basis_is_crational || !exponent_is_crational) {
+ // return a plain float
+ return (new numeric(num_basis->power(*num_exponent)))->setflag(status_flags::dynallocated |
+ status_flags::evaluated |
+ status_flags::expanded);
+ }
+
+ const numeric res = num_basis->power(*num_exponent);
+ if (res.is_crational()) {
+ return res;
+ }
+ GINAC_ASSERT(!num_exponent->is_integer()); // has been handled by now
+
+ // ^(c1,n/m) -> *(c1^q,c1^(n/m-q)), 0<(n/m-q)<1, q integer
+ if (basis_is_crational && exponent_is_crational
+ && num_exponent->is_real()
+ && !num_exponent->is_integer()) {
+ const numeric n = num_exponent->numer();
+ const numeric m = num_exponent->denom();
+ numeric r;
+ numeric q = iquo(n, m, r);
+ if (r.is_negative()) {
+ r += m;
+ --q;
+ }
+ if (q.is_zero()) { // the exponent was in the allowed range 0<(n/m)<1
+ if (num_basis->is_rational() && !num_basis->is_integer()) {
+ // try it for numerator and denominator separately, in order to
+ // partially simplify things like (5/8)^(1/3) -> 1/2*5^(1/3)
+ const numeric bnum = num_basis->numer();
+ const numeric bden = num_basis->denom();
+ const numeric res_bnum = bnum.power(*num_exponent);
+ const numeric res_bden = bden.power(*num_exponent);
+ if (res_bnum.is_integer())
+ return (new mul(power(bden,-*num_exponent),res_bnum))->setflag(status_flags::dynallocated | status_flags::evaluated);
+ if (res_bden.is_integer())
+ return (new mul(power(bnum,*num_exponent),res_bden.inverse()))->setflag(status_flags::dynallocated | status_flags::evaluated);
+ }
+ return this->hold();
+ } else {
+ // assemble resulting product, but allowing for a re-evaluation,
+ // because otherwise we'll end up with something like
+ // (7/8)^(4/3) -> 7/8*(1/2*7^(1/3))
+ // instead of 7/16*7^(1/3).
+ ex prod = power(*num_basis,r.div(m));
+ return prod*power(*num_basis,q);
+ }
+ }
+ }
+
+ // ^(^(x,c1),c2) -> ^(x,c1*c2)
+ // (c1, c2 numeric(), c2 integer or -1 < c1 <= 1 or (c1=-1 and c2>0),
+ // case c1==1 should not happen, see below!)
+ if (is_exactly_a<power>(ebasis)) {
+ const power & sub_power = ex_to<power>(ebasis);
+ const ex & sub_basis = sub_power.basis;
+ const ex & sub_exponent = sub_power.exponent;
+ if (is_exactly_a<numeric>(sub_exponent)) {
+ const numeric & num_sub_exponent = ex_to<numeric>(sub_exponent);
+ GINAC_ASSERT(num_sub_exponent!=numeric(1));
+ if (num_exponent->is_integer() || (abs(num_sub_exponent) - (*_num1_p)).is_negative() ||
+ (num_sub_exponent == *_num_1_p && num_exponent->is_positive())) {
+ return power(sub_basis,num_sub_exponent.mul(*num_exponent));
+ }
+ }
+ }
+
+ // ^(*(x,y,z),c1) -> *(x^c1,y^c1,z^c1) (c1 integer)
+ if (num_exponent->is_integer() && is_exactly_a<mul>(ebasis)) {
+ return expand_mul(ex_to<mul>(ebasis), *num_exponent, 0);
+ }
+
+ // (2*x + 6*y)^(-4) -> 1/16*(x + 3*y)^(-4)
+ if (num_exponent->is_integer() && is_exactly_a<add>(ebasis)) {
+ numeric icont = ebasis.integer_content();
+ const numeric lead_coeff =
+ ex_to<numeric>(ex_to<add>(ebasis).seq.begin()->coeff).div(icont);
+
+ const bool canonicalizable = lead_coeff.is_integer();
+ const bool unit_normal = lead_coeff.is_pos_integer();
+ if (canonicalizable && (! unit_normal))
+ icont = icont.mul(*_num_1_p);
+
+ if (canonicalizable && (icont != *_num1_p)) {
+ const add& addref = ex_to<add>(ebasis);
+ add* addp = new add(addref);
+ addp->setflag(status_flags::dynallocated);
+ addp->clearflag(status_flags::hash_calculated);
+ addp->overall_coeff = ex_to<numeric>(addp->overall_coeff).div_dyn(icont);
+ for (epvector::iterator i = addp->seq.begin(); i != addp->seq.end(); ++i)
+ i->coeff = ex_to<numeric>(i->coeff).div_dyn(icont);
+
+ const numeric c = icont.power(*num_exponent);
+ if (likely(c != *_num1_p))
+ return (new mul(power(*addp, *num_exponent), c))->setflag(status_flags::dynallocated);
+ else
+ return power(*addp, *num_exponent);
+ }
+ }
+
+ // ^(*(...,x;c1),c2) -> *(^(*(...,x;1),c2),c1^c2) (c1, c2 numeric(), c1>0)
+ // ^(*(...,x;c1),c2) -> *(^(*(...,x;-1),c2),(-c1)^c2) (c1, c2 numeric(), c1<0)
+ if (is_exactly_a<mul>(ebasis)) {
+ GINAC_ASSERT(!num_exponent->is_integer()); // should have been handled above
+ const mul & mulref = ex_to<mul>(ebasis);
+ if (!mulref.overall_coeff.is_equal(_ex1)) {
+ const numeric & num_coeff = ex_to<numeric>(mulref.overall_coeff);
+ if (num_coeff.is_real()) {
+ if (num_coeff.is_positive()) {
+ mul *mulp = new mul(mulref);
+ mulp->overall_coeff = _ex1;
+ mulp->setflag(status_flags::dynallocated);
+ mulp->clearflag(status_flags::evaluated);
+ mulp->clearflag(status_flags::hash_calculated);
+ return (new mul(power(*mulp,exponent),
+ power(num_coeff,*num_exponent)))->setflag(status_flags::dynallocated);
+ } else {
+ GINAC_ASSERT(num_coeff.compare(*_num0_p)<0);
+ if (!num_coeff.is_equal(*_num_1_p)) {
+ mul *mulp = new mul(mulref);
+ mulp->overall_coeff = _ex_1;
+ mulp->setflag(status_flags::dynallocated);
+ mulp->clearflag(status_flags::evaluated);
+ mulp->clearflag(status_flags::hash_calculated);
+ return (new mul(power(*mulp,exponent),
+ power(abs(num_coeff),*num_exponent)))->setflag(status_flags::dynallocated);
+ }
+ }
+ }
+ }
+ }
+
+ // ^(nc,c1) -> ncmul(nc,nc,...) (c1 positive integer, unless nc is a matrix)
+ if (num_exponent->is_pos_integer() &&
+ ebasis.return_type() != return_types::commutative &&
+ !is_a<matrix>(ebasis)) {
+ return ncmul(exvector(num_exponent->to_int(), ebasis), true);
+ }
+ }
+
+ if (are_ex_trivially_equal(ebasis,basis) &&
+ are_ex_trivially_equal(eexponent,exponent)) {
+ return this->hold();
+ }
+ return (new power(ebasis, eexponent))->setflag(status_flags::dynallocated |
+ status_flags::evaluated);
}
ex power::evalf(int level) const
{
- debugmsg("power evalf",LOGLEVEL_MEMBER_FUNCTION);
+ ex ebasis;
+ ex eexponent;
+
+ if (level==1) {
+ ebasis = basis;
+ eexponent = exponent;
+ } else if (level == -max_recursion_level) {
+ throw(std::runtime_error("max recursion level reached"));
+ } else {
+ ebasis = basis.evalf(level-1);
+ if (!is_exactly_a<numeric>(exponent))
+ eexponent = exponent.evalf(level-1);
+ else
+ eexponent = exponent;
+ }
+
+ return power(ebasis,eexponent);
+}
- ex ebasis;
- ex eexponent;
-
- if (level==1) {
- ebasis=basis;
- eexponent=exponent;
- } else if (level == -max_recursion_level) {
- throw(std::runtime_error("max recursion level reached"));
- } else {
- ebasis=basis.evalf(level-1);
- eexponent=exponent.evalf(level-1);
- }
+ex power::evalm() const
+{
+ const ex ebasis = basis.evalm();
+ const ex eexponent = exponent.evalm();
+ if (is_a<matrix>(ebasis)) {
+ if (is_exactly_a<numeric>(eexponent)) {
+ return (new matrix(ex_to<matrix>(ebasis).pow(eexponent)))->setflag(status_flags::dynallocated);
+ }
+ }
+ return (new power(ebasis, eexponent))->setflag(status_flags::dynallocated);
+}
+
+bool power::has(const ex & other, unsigned options) const
+{
+ if (!(options & has_options::algebraic))
+ return basic::has(other, options);
+ if (!is_a<power>(other))
+ return basic::has(other, options);
+ if (!exponent.info(info_flags::integer) ||
+ !other.op(1).info(info_flags::integer))
+ return basic::has(other, options);
+ if (exponent.info(info_flags::posint) &&
+ other.op(1).info(info_flags::posint) &&
+ ex_to<numeric>(exponent) > ex_to<numeric>(other.op(1)) &&
+ basis.match(other.op(0)))
+ return true;
+ if (exponent.info(info_flags::negint) &&
+ other.op(1).info(info_flags::negint) &&
+ ex_to<numeric>(exponent) < ex_to<numeric>(other.op(1)) &&
+ basis.match(other.op(0)))
+ return true;
+ return basic::has(other, options);
+}
+
+// from mul.cpp
+extern bool tryfactsubs(const ex &, const ex &, int &, exmap&);
+
+ex power::subs(const exmap & m, unsigned options) const
+{
+ const ex &subsed_basis = basis.subs(m, options);
+ const ex &subsed_exponent = exponent.subs(m, options);
+
+ if (!are_ex_trivially_equal(basis, subsed_basis)
+ || !are_ex_trivially_equal(exponent, subsed_exponent))
+ return power(subsed_basis, subsed_exponent).subs_one_level(m, options);
+
+ if (!(options & subs_options::algebraic))
+ return subs_one_level(m, options);
+
+ for (exmap::const_iterator it = m.begin(); it != m.end(); ++it) {
+ int nummatches = std::numeric_limits<int>::max();
+ exmap repls;
+ if (tryfactsubs(*this, it->first, nummatches, repls)) {
+ ex anum = it->second.subs(repls, subs_options::no_pattern);
+ ex aden = it->first.subs(repls, subs_options::no_pattern);
+ ex result = (*this)*power(anum/aden, nummatches);
+ return (ex_to<basic>(result)).subs_one_level(m, options);
+ }
+ }
+
+ return subs_one_level(m, options);
+}
- return power(ebasis,eexponent);
+ex power::eval_ncmul(const exvector & v) const
+{
+ return inherited::eval_ncmul(v);
}
-ex power::subs(lst const & ls, lst const & lr) const
+ex power::conjugate() const
{
- ex const & subsed_basis=basis.subs(ls,lr);
- ex const & subsed_exponent=exponent.subs(ls,lr);
+ // conjugate(pow(x,y))==pow(conjugate(x),conjugate(y)) unless on the
+ // branch cut which runs along the negative real axis.
+ if (basis.info(info_flags::positive)) {
+ ex newexponent = exponent.conjugate();
+ if (are_ex_trivially_equal(exponent, newexponent)) {
+ return *this;
+ }
+ return (new power(basis, newexponent))->setflag(status_flags::dynallocated);
+ }
+ if (exponent.info(info_flags::integer)) {
+ ex newbasis = basis.conjugate();
+ if (are_ex_trivially_equal(basis, newbasis)) {
+ return *this;
+ }
+ return (new power(newbasis, exponent))->setflag(status_flags::dynallocated);
+ }
+ return conjugate_function(*this).hold();
+}
- if (are_ex_trivially_equal(basis,subsed_basis)&&
- are_ex_trivially_equal(exponent,subsed_exponent)) {
- return *this;
- }
-
- return power(subsed_basis, subsed_exponent);
+ex power::real_part() const
+{
+ // basis == a+I*b, exponent == c+I*d
+ const ex a = basis.real_part();
+ const ex c = exponent.real_part();
+ if (basis.is_equal(a) && exponent.is_equal(c)) {
+ // Re(a^c)
+ return *this;
+ }
+
+ const ex b = basis.imag_part();
+ if (exponent.info(info_flags::integer)) {
+ // Re((a+I*b)^c) w/ c ∈ ℤ
+ long N = ex_to<numeric>(c).to_long();
+ // Use real terms in Binomial expansion to construct
+ // Re(expand(power(a+I*b, N))).
+ long NN = N > 0 ? N : -N;
+ ex numer = N > 0 ? _ex1 : power(power(a,2) + power(b,2), NN);
+ ex result = 0;
+ for (long n = 0; n <= NN; n += 2) {
+ ex term = binomial(NN, n) * power(a, NN-n) * power(b, n) / numer;
+ if (n % 4 == 0) {
+ result += term; // sign: I^n w/ n == 4*m
+ } else {
+ result -= term; // sign: I^n w/ n == 4*m+2
+ }
+ }
+ return result;
+ }
+
+ // Re((a+I*b)^(c+I*d))
+ const ex d = exponent.imag_part();
+ return power(abs(basis),c)*exp(-d*atan2(b,a))*cos(c*atan2(b,a)+d*log(abs(basis)));
}
-ex power::simplify_ncmul(exvector const & v) const
+ex power::imag_part() const
{
- return basic::simplify_ncmul(v);
+ const ex a = basis.real_part();
+ const ex c = exponent.real_part();
+ if (basis.is_equal(a) && exponent.is_equal(c)) {
+ // Im(a^c)
+ return 0;
+ }
+
+ const ex b = basis.imag_part();
+ if (exponent.info(info_flags::integer)) {
+ // Im((a+I*b)^c) w/ c ∈ ℤ
+ long N = ex_to<numeric>(c).to_long();
+ // Use imaginary terms in Binomial expansion to construct
+ // Im(expand(power(a+I*b, N))).
+ long p = N > 0 ? 1 : 3; // modulus for positive sign
+ long NN = N > 0 ? N : -N;
+ ex numer = N > 0 ? _ex1 : power(power(a,2) + power(b,2), NN);
+ ex result = 0;
+ for (long n = 1; n <= NN; n += 2) {
+ ex term = binomial(NN, n) * power(a, NN-n) * power(b, n) / numer;
+ if (n % 4 == p) {
+ result += term; // sign: I^n w/ n == 4*m+p
+ } else {
+ result -= term; // sign: I^n w/ n == 4*m+2+p
+ }
+ }
+ return result;
+ }
+
+ // Im((a+I*b)^(c+I*d))
+ const ex d = exponent.imag_part();
+ return power(abs(basis),c)*exp(-d*atan2(b,a))*sin(c*atan2(b,a)+d*log(abs(basis)));
}
// protected
-int power::compare_same_type(basic const & other) const
+/** Implementation of ex::diff() for a power.
+ * @see ex::diff */
+ex power::derivative(const symbol & s) const
{
- GINAC_ASSERT(is_exactly_of_type(other, power));
- power const & o=static_cast<power const &>(const_cast<basic &>(other));
+ if (is_a<numeric>(exponent)) {
+ // D(b^r) = r * b^(r-1) * D(b) (faster than the formula below)
+ epvector newseq;
+ newseq.reserve(2);
+ newseq.push_back(expair(basis, exponent - _ex1));
+ newseq.push_back(expair(basis.diff(s), _ex1));
+ return mul(newseq, exponent);
+ } else {
+ // D(b^e) = b^e * (D(e)*ln(b) + e*D(b)/b)
+ return mul(*this,
+ add(mul(exponent.diff(s), log(basis)),
+ mul(mul(exponent, basis.diff(s)), power(basis, _ex_1))));
+ }
+}
- int cmpval;
- cmpval=basis.compare(o.basis);
- if (cmpval==0) {
- return exponent.compare(o.exponent);
- }
- return cmpval;
+int power::compare_same_type(const basic & other) const
+{
+ GINAC_ASSERT(is_exactly_a<power>(other));
+ const power &o = static_cast<const power &>(other);
+
+ int cmpval = basis.compare(o.basis);
+ if (cmpval)
+ return cmpval;
+ else
+ return exponent.compare(o.exponent);
}
-unsigned power::return_type(void) const
+unsigned power::return_type() const
{
- return basis.return_type();
+ return basis.return_type();
}
-
-unsigned power::return_type_tinfo(void) const
+
+return_type_t power::return_type_tinfo() const
{
- return basis.return_type_tinfo();
+ return basis.return_type_tinfo();
}
ex power::expand(unsigned options) const
{
- ex expanded_basis=basis.expand(options);
-
- if (!is_ex_exactly_of_type(exponent,numeric)||
- !ex_to_numeric(exponent).is_integer()) {
- if (are_ex_trivially_equal(basis,expanded_basis)) {
- return this->hold();
- } else {
- return (new power(expanded_basis,exponent))->
- setflag(status_flags::dynallocated);
- }
- }
-
- // integer numeric exponent
- numeric const & num_exponent=ex_to_numeric(exponent);
- int int_exponent = num_exponent.to_int();
-
- if (int_exponent > 0 && is_ex_exactly_of_type(expanded_basis,add)) {
- return expand_add(ex_to_add(expanded_basis), int_exponent);
- }
-
- if (is_ex_exactly_of_type(expanded_basis,mul)) {
- return expand_mul(ex_to_mul(expanded_basis), num_exponent);
- }
-
- // cannot expand further
- if (are_ex_trivially_equal(basis,expanded_basis)) {
- return this->hold();
- } else {
- return (new power(expanded_basis,exponent))->
- setflag(status_flags::dynallocated);
- }
+ if (is_a<symbol>(basis) && exponent.info(info_flags::integer)) {
+ // A special case worth optimizing.
+ setflag(status_flags::expanded);
+ return *this;
+ }
+
+ // (x*p)^c -> x^c * p^c, if p>0
+ // makes sense before expanding the basis
+ if (is_exactly_a<mul>(basis) && !basis.info(info_flags::indefinite)) {
+ const mul &m = ex_to<mul>(basis);
+ exvector prodseq;
+ epvector powseq;
+ prodseq.reserve(m.seq.size() + 1);
+ powseq.reserve(m.seq.size() + 1);
+ epvector::const_iterator last = m.seq.end();
+ epvector::const_iterator cit = m.seq.begin();
+ bool possign = true;
+
+ // search for positive/negative factors
+ while (cit!=last) {
+ ex e=m.recombine_pair_to_ex(*cit);
+ if (e.info(info_flags::positive))
+ prodseq.push_back(pow(e, exponent).expand(options));
+ else if (e.info(info_flags::negative)) {
+ prodseq.push_back(pow(-e, exponent).expand(options));
+ possign = !possign;
+ } else
+ powseq.push_back(*cit);
+ ++cit;
+ }
+
+ // take care on the numeric coefficient
+ ex coeff=(possign? _ex1 : _ex_1);
+ if (m.overall_coeff.info(info_flags::positive) && m.overall_coeff != _ex1)
+ prodseq.push_back(power(m.overall_coeff, exponent));
+ else if (m.overall_coeff.info(info_flags::negative) && m.overall_coeff != _ex_1)
+ prodseq.push_back(power(-m.overall_coeff, exponent));
+ else
+ coeff *= m.overall_coeff;
+
+ // If positive/negative factors are found, then extract them.
+ // In either case we set a flag to avoid the second run on a part
+ // which does not have positive/negative terms.
+ if (prodseq.size() > 0) {
+ ex newbasis = coeff*mul(powseq);
+ ex_to<basic>(newbasis).setflag(status_flags::purely_indefinite);
+ return ((new mul(prodseq))->setflag(status_flags::dynallocated)*(new power(newbasis, exponent))->setflag(status_flags::dynallocated).expand(options)).expand(options);
+ } else
+ ex_to<basic>(basis).setflag(status_flags::purely_indefinite);
+ }
+
+ const ex expanded_basis = basis.expand(options);
+ const ex expanded_exponent = exponent.expand(options);
+
+ // x^(a+b) -> x^a * x^b
+ if (is_exactly_a<add>(expanded_exponent)) {
+ const add &a = ex_to<add>(expanded_exponent);
+ exvector distrseq;
+ distrseq.reserve(a.seq.size() + 1);
+ epvector::const_iterator last = a.seq.end();
+ epvector::const_iterator cit = a.seq.begin();
+ while (cit!=last) {
+ distrseq.push_back(power(expanded_basis, a.recombine_pair_to_ex(*cit)));
+ ++cit;
+ }
+
+ // Make sure that e.g. (x+y)^(2+a) expands the (x+y)^2 factor
+ if (ex_to<numeric>(a.overall_coeff).is_integer()) {
+ const numeric &num_exponent = ex_to<numeric>(a.overall_coeff);
+ int int_exponent = num_exponent.to_int();
+ if (int_exponent > 0 && is_exactly_a<add>(expanded_basis))
+ distrseq.push_back(expand_add(ex_to<add>(expanded_basis), int_exponent, options));
+ else
+ distrseq.push_back(power(expanded_basis, a.overall_coeff));
+ } else
+ distrseq.push_back(power(expanded_basis, a.overall_coeff));
+
+ // Make sure that e.g. (x+y)^(1+a) -> x*(x+y)^a + y*(x+y)^a
+ ex r = (new mul(distrseq))->setflag(status_flags::dynallocated);
+ return r.expand(options);
+ }
+
+ if (!is_exactly_a<numeric>(expanded_exponent) ||
+ !ex_to<numeric>(expanded_exponent).is_integer()) {
+ if (are_ex_trivially_equal(basis,expanded_basis) && are_ex_trivially_equal(exponent,expanded_exponent)) {
+ return this->hold();
+ } else {
+ return (new power(expanded_basis,expanded_exponent))->setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));
+ }
+ }
+
+ // integer numeric exponent
+ const numeric & num_exponent = ex_to<numeric>(expanded_exponent);
+ int int_exponent = num_exponent.to_int();
+
+ // (x+y)^n, n>0
+ if (int_exponent > 0 && is_exactly_a<add>(expanded_basis))
+ return expand_add(ex_to<add>(expanded_basis), int_exponent, options);
+
+ // (x*y)^n -> x^n * y^n
+ if (is_exactly_a<mul>(expanded_basis))
+ return expand_mul(ex_to<mul>(expanded_basis), num_exponent, options, true);
+
+ // cannot expand further
+ if (are_ex_trivially_equal(basis,expanded_basis) && are_ex_trivially_equal(exponent,expanded_exponent))
+ return this->hold();
+ else
+ return (new power(expanded_basis,expanded_exponent))->setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));
}
//////////
// non-virtual functions in this class
//////////
-ex power::expand_add(add const & a, int const n) const
-{
- // expand a^n where a is an add and n is an integer
-
- if (n==2) {
- return expand_add_2(a);
- }
-
- int m=a.nops();
- exvector sum;
- sum.reserve((n+1)*(m-1));
- intvector k(m-1);
- intvector k_cum(m-1); // k_cum[l]:=sum(i=0,l,k[l]);
- intvector upper_limit(m-1);
- int l;
-
- for (int l=0; l<m-1; l++) {
- k[l]=0;
- k_cum[l]=0;
- upper_limit[l]=n;
- }
-
- while (1) {
- exvector term;
- term.reserve(m+1);
- for (l=0; l<m-1; l++) {
- ex const & b=a.op(l);
- GINAC_ASSERT(!is_ex_exactly_of_type(b,add));
- GINAC_ASSERT(!is_ex_exactly_of_type(b,power)||
- !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric)||
- !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer());
- if (is_ex_exactly_of_type(b,mul)) {
- term.push_back(expand_mul(ex_to_mul(b),numeric(k[l])));
- } else {
- term.push_back(power(b,k[l]));
- }
- }
-
- ex const & b=a.op(l);
- GINAC_ASSERT(!is_ex_exactly_of_type(b,add));
- GINAC_ASSERT(!is_ex_exactly_of_type(b,power)||
- !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric)||
- !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer());
- if (is_ex_exactly_of_type(b,mul)) {
- term.push_back(expand_mul(ex_to_mul(b),numeric(n-k_cum[m-2])));
- } else {
- term.push_back(power(b,n-k_cum[m-2]));
- }
-
- numeric f=binomial(numeric(n),numeric(k[0]));
- for (l=1; l<m-1; l++) {
- f=f*binomial(numeric(n-k_cum[l-1]),numeric(k[l]));
- }
- term.push_back(f);
-
- /*
- cout << "begin term" << endl;
- for (int i=0; i<m-1; i++) {
- cout << "k[" << i << "]=" << k[i] << endl;
- cout << "k_cum[" << i << "]=" << k_cum[i] << endl;
- cout << "upper_limit[" << i << "]=" << upper_limit[i] << endl;
- }
- for (exvector::const_iterator cit=term.begin(); cit!=term.end(); ++cit) {
- cout << *cit << endl;
- }
- cout << "end term" << endl;
- */
-
- // TODO: optimize this
- sum.push_back((new mul(term))->setflag(status_flags::dynallocated));
-
- // increment k[]
- l=m-2;
- while ((l>=0)&&((++k[l])>upper_limit[l])) {
- k[l]=0;
- l--;
- }
- if (l<0) break;
-
- // recalc k_cum[] and upper_limit[]
- if (l==0) {
- k_cum[0]=k[0];
- } else {
- k_cum[l]=k_cum[l-1]+k[l];
- }
- for (int i=l+1; i<m-1; i++) {
- k_cum[i]=k_cum[i-1]+k[i];
- }
-
- for (int i=l+1; i<m-1; i++) {
- upper_limit[i]=n-k_cum[i-1];
- }
- }
- return (new add(sum))->setflag(status_flags::dynallocated);
-}
+namespace { // anonymous namespace for power::expand_add() helpers
-/*
-ex power::expand_add_2(add const & a) const
-{
- // special case: expand a^2 where a is an add
-
- epvector sum;
- sum.reserve((a.seq.size()*(a.seq.size()+1))/2);
- epvector::const_iterator last=a.seq.end();
-
- for (epvector::const_iterator cit0=a.seq.begin(); cit0!=last; ++cit0) {
- ex const & b=a.recombine_pair_to_ex(*cit0);
- GINAC_ASSERT(!is_ex_exactly_of_type(b,add));
- GINAC_ASSERT(!is_ex_exactly_of_type(b,power)||
- !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric)||
- !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer());
- if (is_ex_exactly_of_type(b,mul)) {
- sum.push_back(a.split_ex_to_pair(expand_mul(ex_to_mul(b),numTWO())));
- } else {
- sum.push_back(a.split_ex_to_pair((new power(b,exTWO()))->
- setflag(status_flags::dynallocated)));
- }
- for (epvector::const_iterator cit1=cit0+1; cit1!=last; ++cit1) {
- sum.push_back(a.split_ex_to_pair((new mul(a.recombine_pair_to_ex(*cit0),
- a.recombine_pair_to_ex(*cit1)))->
- setflag(status_flags::dynallocated),
- exTWO()));
- }
- }
-
- GINAC_ASSERT(sum.size()==(a.seq.size()*(a.seq.size()+1))/2);
-
- return (new add(sum))->setflag(status_flags::dynallocated);
-}
-*/
-
-ex power::expand_add_2(add const & a) const
-{
- // special case: expand a^2 where a is an add
-
- epvector sum;
- unsigned a_nops=a.nops();
- sum.reserve((a_nops*(a_nops+1))/2);
- epvector::const_iterator last=a.seq.end();
-
- // power(+(x,...,z;c),2)=power(+(x,...,z;0),2)+2*c*+(x,...,z;0)+c*c
- // first part: ignore overall_coeff and expand other terms
- for (epvector::const_iterator cit0=a.seq.begin(); cit0!=last; ++cit0) {
- ex const & r=(*cit0).rest;
- ex const & c=(*cit0).coeff;
-
- GINAC_ASSERT(!is_ex_exactly_of_type(r,add));
- GINAC_ASSERT(!is_ex_exactly_of_type(r,power)||
- !is_ex_exactly_of_type(ex_to_power(r).exponent,numeric)||
- !ex_to_numeric(ex_to_power(r).exponent).is_pos_integer()||
- !is_ex_exactly_of_type(ex_to_power(r).basis,add)||
- !is_ex_exactly_of_type(ex_to_power(r).basis,mul)||
- !is_ex_exactly_of_type(ex_to_power(r).basis,power));
-
- if (are_ex_trivially_equal(c,exONE())) {
- if (is_ex_exactly_of_type(r,mul)) {
- sum.push_back(expair(expand_mul(ex_to_mul(r),numTWO()),exONE()));
- } else {
- sum.push_back(expair((new power(r,exTWO()))->setflag(status_flags::dynallocated),
- exONE()));
- }
- } else {
- if (is_ex_exactly_of_type(r,mul)) {
- sum.push_back(expair(expand_mul(ex_to_mul(r),numTWO()),
- ex_to_numeric(c).power_dyn(numTWO())));
- } else {
- sum.push_back(expair((new power(r,exTWO()))->setflag(status_flags::dynallocated),
- ex_to_numeric(c).power_dyn(numTWO())));
- }
- }
-
- for (epvector::const_iterator cit1=cit0+1; cit1!=last; ++cit1) {
- ex const & r1=(*cit1).rest;
- ex const & c1=(*cit1).coeff;
- sum.push_back(a.combine_ex_with_coeff_to_pair((new mul(r,r1))->setflag(status_flags::dynallocated),
- numTWO().mul(ex_to_numeric(c)).mul_dyn(ex_to_numeric(c1))));
- }
- }
-
- GINAC_ASSERT(sum.size()==(a.seq.size()*(a.seq.size()+1))/2);
-
- // second part: add terms coming from overall_factor (if != 0)
- if (!a.overall_coeff.is_equal(exZERO())) {
- for (epvector::const_iterator cit=a.seq.begin(); cit!=a.seq.end(); ++cit) {
- sum.push_back(a.combine_pair_with_coeff_to_pair(*cit,ex_to_numeric(a.overall_coeff).mul_dyn(numTWO())));
- }
- sum.push_back(expair(ex_to_numeric(a.overall_coeff).power_dyn(numTWO()),exONE()));
- }
-
- GINAC_ASSERT(sum.size()==(a_nops*(a_nops+1))/2);
-
- return (new add(sum))->setflag(status_flags::dynallocated);
-}
-
-ex power::expand_mul(mul const & m, numeric const & n) const
-{
- // expand m^n where m is a mul and n is and integer
-
- if (n.is_equal(numZERO())) {
- return exONE();
- }
-
- epvector distrseq;
- distrseq.reserve(m.seq.size());
- epvector::const_iterator last=m.seq.end();
- epvector::const_iterator cit=m.seq.begin();
- while (cit!=last) {
- if (is_ex_exactly_of_type((*cit).rest,numeric)) {
- distrseq.push_back(m.combine_pair_with_coeff_to_pair(*cit,n));
- } else {
- // it is safe not to call mul::combine_pair_with_coeff_to_pair()
- // since n is an integer
- distrseq.push_back(expair((*cit).rest,
- ex_to_numeric((*cit).coeff).mul(n)));
- }
- ++cit;
- }
- return (new mul(distrseq,ex_to_numeric(m.overall_coeff).power_dyn(n)))
- ->setflag(status_flags::dynallocated);
+/** Helper class to generate all bounded combinatorial partitions of an integer
+ * n with exactly m parts (including zero parts) in non-decreasing order.
+ */
+class partition_generator {
+private:
+ // Partitions n into m parts, not including zero parts.
+ // (Cf. OEIS sequence A008284; implementation adapted from Jörg Arndt's
+ // FXT library)
+ struct mpartition2
+ {
+ // partition: x[1] + x[2] + ... + x[m] = n and sentinel x[0] == 0
+ std::vector<int> x;
+ int n; // n>0
+ int m; // 0<m<=n
+ mpartition2(unsigned n_, unsigned m_)
+ : x(m_+1), n(n_), m(m_)
+ {
+ for (int k=1; k<m; ++k)
+ x[k] = 1;
+ x[m] = n - m + 1;
+ }
+ bool next_partition()
+ {
+ int u = x[m]; // last element
+ int k = m;
+ int s = u;
+ while (--k) {
+ s += x[k];
+ if (x[k] + 2 <= u)
+ break;
+ }
+ if (k==0)
+ return false; // current is last
+ int f = x[k] + 1;
+ while (k < m) {
+ x[k] = f;
+ s -= f;
+ ++k;
+ }
+ x[m] = s;
+ return true;
+ }
+ } mpgen;
+ int m; // number of parts 0<m<=n
+ mutable std::vector<int> partition; // current partition
+public:
+ partition_generator(unsigned n_, unsigned m_)
+ : mpgen(n_, 1), m(m_), partition(m_)
+ { }
+ // returns current partition in non-decreasing order, padded with zeros
+ const std::vector<int>& current() const
+ {
+ for (int i = 0; i < m - mpgen.m; ++i)
+ partition[i] = 0; // pad with zeros
+
+ for (int i = m - mpgen.m; i < m; ++i)
+ partition[i] = mpgen.x[i - m + mpgen.m + 1];
+
+ return partition;
+ }
+ bool next()
+ {
+ if (!mpgen.next_partition()) {
+ if (mpgen.m == m || mpgen.m == mpgen.n)
+ return false; // current is last
+ // increment number of parts
+ mpgen = mpartition2(mpgen.n, mpgen.m + 1);
+ }
+ return true;
+ }
+};
+
+/** Helper class to generate all compositions of a partition of an integer n,
+ * starting with the compositions which has non-decreasing order.
+ */
+class composition_generator {
+private:
+ // Generates all distinct permutations of a multiset.
+ // (Based on Aaron Williams' algorithm 1 from "Loopless Generation of
+ // Multiset Permutations using a Constant Number of Variables by Prefix
+ // Shifts." <http://webhome.csc.uvic.ca/~haron/CoolMulti.pdf>)
+ struct coolmulti {
+ // element of singly linked list
+ struct element {
+ int value;
+ element* next;
+ element(int val, element* n)
+ : value(val), next(n) {}
+ ~element()
+ { // recurses down to the end of the singly linked list
+ delete next;
+ }
+ };
+ element *head, *i, *after_i;
+ // NB: Partition must be sorted in non-decreasing order.
+ explicit coolmulti(const std::vector<int>& partition)
+ {
+ head = NULL;
+ for (unsigned n = 0; n < partition.size(); ++n) {
+ head = new element(partition[n], head);
+ if (n <= 1)
+ i = head;
+ }
+ after_i = i->next;
+ }
+ ~coolmulti()
+ { // deletes singly linked list
+ delete head;
+ }
+ void next_permutation()
+ {
+ element *before_k;
+ if (after_i->next != NULL && i->value >= after_i->next->value)
+ before_k = after_i;
+ else
+ before_k = i;
+ element *k = before_k->next;
+ before_k->next = k->next;
+ k->next = head;
+ if (k->value < head->value)
+ i = k;
+ after_i = i->next;
+ head = k;
+ }
+ bool finished() const
+ {
+ return after_i->next == NULL && after_i->value >= head->value;
+ }
+ } cmgen;
+ bool atend; // needed for simplifying iteration over permutations
+ bool trivial; // likewise, true if all elements are equal
+ mutable std::vector<int> composition; // current compositions
+public:
+ explicit composition_generator(const std::vector<int>& partition)
+ : cmgen(partition), atend(false), trivial(true), composition(partition.size())
+ {
+ for (unsigned i=1; i<partition.size(); ++i)
+ trivial = trivial && (partition[0] == partition[i]);
+ }
+ const std::vector<int>& current() const
+ {
+ coolmulti::element* it = cmgen.head;
+ size_t i = 0;
+ while (it != NULL) {
+ composition[i] = it->value;
+ it = it->next;
+ ++i;
+ }
+ return composition;
+ }
+ bool next()
+ {
+ // This ugly contortion is needed because the original coolmulti
+ // algorithm requires code duplication of the payload procedure,
+ // one before the loop and one inside it.
+ if (trivial || atend)
+ return false;
+ cmgen.next_permutation();
+ atend = cmgen.finished();
+ return true;
+ }
+};
+
+/** Helper function to compute the multinomial coefficient n!/(p1!*p2!*...*pk!)
+ * where n = p1+p2+...+pk, i.e. p is a partition of n.
+ */
+const numeric
+multinomial_coefficient(const std::vector<int> & p)
+{
+ numeric n = 0, d = 1;
+ std::vector<int>::const_iterator it = p.begin(), itend = p.end();
+ while (it != itend) {
+ n += numeric(*it);
+ d *= factorial(numeric(*it));
+ ++it;
+ }
+ return factorial(numeric(n)) / d;
}
-/*
-ex power::expand_commutative_3(ex const & basis, numeric const & exponent,
- unsigned options) const
-{
- // obsolete
+} // anonymous namespace
- exvector distrseq;
- epvector splitseq;
+/** expand a^n where a is an add and n is a positive integer.
+ * @see power::expand */
+ex power::expand_add(const add & a, int n, unsigned options) const
+{
+ // The special case power(+(x,...y;x),2) can be optimized better.
+ if (n==2)
+ return expand_add_2(a, options);
+
+ // method:
+ //
+ // Consider base as the sum of all symbolic terms and the overall numeric
+ // coefficient and apply the binomial theorem:
+ // S = power(+(x,...,z;c),n)
+ // = power(+(+(x,...,z;0);c),n)
+ // = sum(binomial(n,k)*power(+(x,...,z;0),k)*c^(n-k), k=1..n) + c^n
+ // Then, apply the multinomial theorem to expand all power(+(x,...,z;0),k):
+ // The multinomial theorem is computed by an outer loop over all
+ // partitions of the exponent and an inner loop over all compositions of
+ // that partition. This method makes the expansion a combinatorial
+ // problem and allows us to directly construct the expanded sum and also
+ // to re-use the multinomial coefficients (since they depend only on the
+ // partition, not on the composition).
+ //
+ // multinomial power(+(x,y,z;0),3) example:
+ // partition : compositions : multinomial coefficient
+ // [0,0,3] : [3,0,0],[0,3,0],[0,0,3] : 3!/(3!*0!*0!) = 1
+ // [0,1,2] : [2,1,0],[1,2,0],[2,0,1],... : 3!/(2!*1!*0!) = 3
+ // [1,1,1] : [1,1,1] : 3!/(1!*1!*1!) = 6
+ // => (x + y + z)^3 =
+ // x^3 + y^3 + z^3
+ // + 3*x^2*y + 3*x*y^2 + 3*y^2*z + 3*y*z^2 + 3*x*z^2 + 3*x^2*z
+ // + 6*x*y*z
+ //
+ // multinomial power(+(x,y,z;0),4) example:
+ // partition : compositions : multinomial coefficient
+ // [0,0,4] : [4,0,0],[0,4,0],[0,0,4] : 4!/(4!*0!*0!) = 1
+ // [0,1,3] : [3,1,0],[1,3,0],[3,0,1],... : 4!/(3!*1!*0!) = 4
+ // [0,2,2] : [2,2,0],[2,0,2],[0,2,2] : 4!/(2!*2!*0!) = 6
+ // [1,1,2] : [2,1,1],[1,2,1],[1,1,2] : 4!/(2!*1!*1!) = 12
+ // (no [1,1,1,1] partition since it has too many parts)
+ // => (x + y + z)^4 =
+ // x^4 + y^4 + z^4
+ // + 4*x^3*y + 4*x*y^3 + 4*y^3*z + 4*y*z^3 + 4*x*z^3 + 4*x^3*z
+ // + 6*x^2*y^2 + 6*y^2*z^2 + 6*x^2*z^2
+ // + 12*x^2*y*z + 12*x*y^2*z + 12*x*y*z^2
+ //
+ // Summary:
+ // r = 0
+ // for k from 0 to n:
+ // f = c^(n-k)*binomial(n,k)
+ // for p in all partitions of n with m parts (including zero parts):
+ // h = f * multinomial coefficient of p
+ // for c in all compositions of p:
+ // t = 1
+ // for e in all elements of c:
+ // t = t * a[e]^e
+ // r = r + h*t
+ // return r
+
+ epvector result;
+ // The number of terms will be the number of combinatorial compositions,
+ // i.e. the number of unordered arrangements of m nonnegative integers
+ // which sum up to n. It is frequently written as C_n(m) and directly
+ // related with binomial coefficients: binomial(n+m-1,m-1).
+ size_t result_size = binomial(numeric(n+a.nops()-1), numeric(a.nops()-1)).to_int();
+ if (!a.overall_coeff.is_zero()) {
+ // the result's overall_coeff is one of the terms
+ --result_size;
+ }
+ result.reserve(result_size);
+
+ // Iterate over all terms in binomial expansion of
+ // S = power(+(x,...,z;c),n)
+ // = sum(binomial(n,k)*power(+(x,...,z;0),k)*c^(n-k), k=1..n) + c^n
+ for (int k = 1; k <= n; ++k) {
+ numeric binomial_coefficient; // binomial(n,k)*c^(n-k)
+ if (a.overall_coeff.is_zero()) {
+ // degenerate case with zero overall_coeff:
+ // apply multinomial theorem directly to power(+(x,...z;0),n)
+ binomial_coefficient = 1;
+ if (k < n) {
+ continue;
+ }
+ } else {
+ binomial_coefficient = binomial(numeric(n), numeric(k)) * pow(ex_to<numeric>(a.overall_coeff), numeric(n-k));
+ }
+
+ // Multinomial expansion of power(+(x,...,z;0),k)*c^(n-k):
+ // Iterate over all partitions of k with exactly as many parts as
+ // there are symbolic terms in the basis (including zero parts).
+ partition_generator partitions(k, a.seq.size());
+ do {
+ const std::vector<int>& partition = partitions.current();
+ // All monomials of this partition have the same number of terms and the same coefficient.
+ const unsigned msize = count_if(partition.begin(), partition.end(), bind2nd(std::greater<int>(), 0));
+ const numeric coeff = multinomial_coefficient(partition) * binomial_coefficient;
+
+ // Iterate over all compositions of the current partition.
+ composition_generator compositions(partition);
+ do {
+ const std::vector<int>& exponent = compositions.current();
+ exvector monomial;
+ monomial.reserve(msize);
+ numeric factor = coeff;
+ for (unsigned i = 0; i < exponent.size(); ++i) {
+ const ex & r = a.seq[i].rest;
+ GINAC_ASSERT(!is_exactly_a<add>(r));
+ GINAC_ASSERT(!is_exactly_a<power>(r) ||
+ !is_exactly_a<numeric>(ex_to<power>(r).exponent) ||
+ !ex_to<numeric>(ex_to<power>(r).exponent).is_pos_integer() ||
+ !is_exactly_a<add>(ex_to<power>(r).basis) ||
+ !is_exactly_a<mul>(ex_to<power>(r).basis) ||
+ !is_exactly_a<power>(ex_to<power>(r).basis));
+ GINAC_ASSERT(is_exactly_a<numeric>(a.seq[i].coeff));
+ const numeric & c = ex_to<numeric>(a.seq[i].coeff);
+ if (exponent[i] == 0) {
+ // optimize away
+ } else if (exponent[i] == 1) {
+ // optimized
+ monomial.push_back(r);
+ if (c != *_num1_p)
+ factor = factor.mul(c);
+ } else { // general case exponent[i] > 1
+ monomial.push_back((new power(r, exponent[i]))->setflag(status_flags::dynallocated));
+ if (c != *_num1_p)
+ factor = factor.mul(c.power(exponent[i]));
+ }
+ }
+ result.push_back(a.combine_ex_with_coeff_to_pair(mul(monomial).expand(options), factor));
+ } while (compositions.next());
+ } while (partitions.next());
+ }
+
+ GINAC_ASSERT(result.size() == result_size);
+
+ if (a.overall_coeff.is_zero()) {
+ return (new add(result))->setflag(status_flags::dynallocated |
+ status_flags::expanded);
+ } else {
+ return (new add(result, ex_to<numeric>(a.overall_coeff).power(n)))->setflag(status_flags::dynallocated |
+ status_flags::expanded);
+ }
+}
- add const & addref=static_cast<add const &>(*basis.bp);
- splitseq=addref.seq;
- splitseq.pop_back();
- ex first_operands=add(splitseq);
- ex last_operand=addref.recombine_pair_to_ex(*(addref.seq.end()-1));
-
- int n=exponent.to_int();
- for (int k=0; k<=n; k++) {
- distrseq.push_back(binomial(n,k)*power(first_operands,numeric(k))*
- power(last_operand,numeric(n-k)));
- }
- return ex((new add(distrseq))->setflag(status_flags::sub_expanded |
- status_flags::expanded |
- status_flags::dynallocated )).
- expand(options);
+/** Special case of power::expand_add. Expands a^2 where a is an add.
+ * @see power::expand_add */
+ex power::expand_add_2(const add & a, unsigned options) const
+{
+ epvector sum;
+ size_t a_nops = a.nops();
+ sum.reserve((a_nops*(a_nops+1))/2);
+ epvector::const_iterator last = a.seq.end();
+
+ // power(+(x,...,z;c),2)=power(+(x,...,z;0),2)+2*c*+(x,...,z;0)+c*c
+ // first part: ignore overall_coeff and expand other terms
+ for (epvector::const_iterator cit0=a.seq.begin(); cit0!=last; ++cit0) {
+ const ex & r = cit0->rest;
+ const ex & c = cit0->coeff;
+
+ GINAC_ASSERT(!is_exactly_a<add>(r));
+ GINAC_ASSERT(!is_exactly_a<power>(r) ||
+ !is_exactly_a<numeric>(ex_to<power>(r).exponent) ||
+ !ex_to<numeric>(ex_to<power>(r).exponent).is_pos_integer() ||
+ !is_exactly_a<add>(ex_to<power>(r).basis) ||
+ !is_exactly_a<mul>(ex_to<power>(r).basis) ||
+ !is_exactly_a<power>(ex_to<power>(r).basis));
+
+ if (c.is_equal(_ex1)) {
+ if (is_exactly_a<mul>(r)) {
+ sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to<mul>(r), *_num2_p, options, true),
+ _ex1));
+ } else {
+ sum.push_back(a.combine_ex_with_coeff_to_pair((new power(r,_ex2))->setflag(status_flags::dynallocated),
+ _ex1));
+ }
+ } else {
+ if (is_exactly_a<mul>(r)) {
+ sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to<mul>(r), *_num2_p, options, true),
+ ex_to<numeric>(c).power_dyn(*_num2_p)));
+ } else {
+ sum.push_back(a.combine_ex_with_coeff_to_pair((new power(r,_ex2))->setflag(status_flags::dynallocated),
+ ex_to<numeric>(c).power_dyn(*_num2_p)));
+ }
+ }
+
+ for (epvector::const_iterator cit1=cit0+1; cit1!=last; ++cit1) {
+ const ex & r1 = cit1->rest;
+ const ex & c1 = cit1->coeff;
+ sum.push_back(a.combine_ex_with_coeff_to_pair(mul(r,r1).expand(options),
+ _num2_p->mul(ex_to<numeric>(c)).mul_dyn(ex_to<numeric>(c1))));
+ }
+ }
+
+ GINAC_ASSERT(sum.size()==(a.seq.size()*(a.seq.size()+1))/2);
+
+ // second part: add terms coming from overall_coeff (if != 0)
+ if (!a.overall_coeff.is_zero()) {
+ epvector::const_iterator i = a.seq.begin(), end = a.seq.end();
+ while (i != end) {
+ sum.push_back(a.combine_pair_with_coeff_to_pair(*i, ex_to<numeric>(a.overall_coeff).mul_dyn(*_num2_p)));
+ ++i;
+ }
+ sum.push_back(expair(ex_to<numeric>(a.overall_coeff).power_dyn(*_num2_p),_ex1));
+ }
+
+ GINAC_ASSERT(sum.size()==(a_nops*(a_nops+1))/2);
+
+ return (new add(sum))->setflag(status_flags::dynallocated | status_flags::expanded);
}
-*/
-/*
-ex power::expand_noncommutative(ex const & basis, numeric const & exponent,
- unsigned options) const
+/** Expand factors of m in m^n where m is a mul and n is an integer.
+ * @see power::expand */
+ex power::expand_mul(const mul & m, const numeric & n, unsigned options, bool from_expand) const
{
- ex rest_power=ex(power(basis,exponent.add(numMINUSONE()))).
- expand(options | expand_options::internal_do_not_expand_power_operands);
-
- return ex(mul(rest_power,basis),0).
- expand(options | expand_options::internal_do_not_expand_mul_operands);
+ GINAC_ASSERT(n.is_integer());
+
+ if (n.is_zero()) {
+ return _ex1;
+ }
+
+ // do not bother to rename indices if there are no any.
+ if (!(options & expand_options::expand_rename_idx) &&
+ m.info(info_flags::has_indices))
+ options |= expand_options::expand_rename_idx;
+ // Leave it to multiplication since dummy indices have to be renamed
+ if ((options & expand_options::expand_rename_idx) &&
+ (get_all_dummy_indices(m).size() > 0) && n.is_positive()) {
+ ex result = m;
+ exvector va = get_all_dummy_indices(m);
+ sort(va.begin(), va.end(), ex_is_less());
+
+ for (int i=1; i < n.to_int(); i++)
+ result *= rename_dummy_indices_uniquely(va, m);
+ return result;
+ }
+
+ epvector distrseq;
+ distrseq.reserve(m.seq.size());
+ bool need_reexpand = false;
+
+ epvector::const_iterator last = m.seq.end();
+ epvector::const_iterator cit = m.seq.begin();
+ while (cit!=last) {
+ expair p = m.combine_pair_with_coeff_to_pair(*cit, n);
+ if (from_expand && is_exactly_a<add>(cit->rest) && ex_to<numeric>(p.coeff).is_pos_integer()) {
+ // this happens when e.g. (a+b)^(1/2) gets squared and
+ // the resulting product needs to be reexpanded
+ need_reexpand = true;
+ }
+ distrseq.push_back(p);
+ ++cit;
+ }
+
+ const mul & result = static_cast<const mul &>((new mul(distrseq, ex_to<numeric>(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated));
+ if (need_reexpand)
+ return ex(result).expand(options);
+ if (from_expand)
+ return result.setflag(status_flags::expanded);
+ return result;
}
-*/
-
-//////////
-// static member variables
-//////////
-
-// protected
-
-unsigned power::precedence=60;
-
-//////////
-// global constants
-//////////
-const power some_power;
-type_info const & typeid_power=typeid(some_power);
+GINAC_BIND_UNARCHIVER(power);
-#ifndef NO_GINAC_NAMESPACE
} // namespace GiNaC
-#endif // ndef NO_GINAC_NAMESPACE