X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fpower.cpp;h=0730e3c8bf7fc385c5d4d1c1a97b6c565997cfab;hp=66181941feef1fbeb407922a2006b9263cf5d9df;hb=dbd9c306a74f1cb258c0d15a346b973b39deaad2;hpb=2862087ce55d944c1ac5d37283944b2b37507fd2 diff --git a/ginac/power.cpp b/ginac/power.cpp index 66181941..0730e3c8 100644 --- a/ginac/power.cpp +++ b/ginac/power.cpp @@ -3,7 +3,7 @@ * Implementation of GiNaC's symbolic exponentiation (basis^exponent). */ /* - * GiNaC Copyright (C) 1999-2001 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 @@ -33,10 +33,10 @@ #include "constant.h" #include "inifcns.h" // for log() in power::derivative() #include "matrix.h" +#include "indexed.h" #include "symbol.h" #include "print.h" #include "archive.h" -#include "debugmsg.h" #include "utils.h" namespace GiNaC { @@ -46,13 +46,10 @@ GINAC_IMPLEMENT_REGISTERED_CLASS(power, basic) typedef std::vector intvector; ////////// -// default ctor, dtor, copy ctor assignment operator and helpers +// default ctor, dtor, copy ctor, assignment operator and helpers ////////// -power::power() : inherited(TINFO_power) -{ - debugmsg("power default ctor",LOGLEVEL_CONSTRUCT); -} +power::power() : inherited(TINFO_power) { } void power::copy(const power & other) { @@ -75,7 +72,6 @@ DEFAULT_DESTROY(power) power::power(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst) { - debugmsg("power ctor from archive_node", LOGLEVEL_CONSTRUCT); n.find_ex("basis", basis, sym_lst); n.find_ex("exponent", exponent, sym_lst); } @@ -121,8 +117,6 @@ static void print_sym_pow(const print_context & c, const symbol &x, int exp) void power::print(const print_context & c, unsigned level) const { - debugmsg("power print", LOGLEVEL_PRINT); - if (is_a(c)) { inherited::print(c, level); @@ -131,7 +125,7 @@ void power::print(const print_context & c, unsigned level) const // Integer powers of symbols are printed in a special, optimized way if (exponent.info(info_flags::integer) - && (is_exactly_a(basis) || is_exactly_a(basis))) { + && (is_a(basis) || is_a(basis))) { int exp = ex_to(exponent).to_int(); if (exp > 0) c.s << '('; @@ -146,7 +140,7 @@ void power::print(const print_context & c, unsigned level) const c.s << ')'; // ^-1 is printed as "1.0/" or with the recip() function of CLN - } else if (exponent.compare(_num_1()) == 0) { + } else if (exponent.is_equal(_ex_1)) { if (is_a(c)) c.s << "recip("; else @@ -166,38 +160,49 @@ void power::print(const print_context & c, unsigned level) const c.s << ')'; } + } else if (is_a(c)) { + + c.s << class_name() << '('; + basis.print(c); + c.s << ','; + exponent.print(c); + c.s << ')'; + } else { - if (exponent.is_equal(_ex1_2())) { - if (is_a(c)) - c.s << "\\sqrt{"; - else - c.s << "sqrt("; + bool is_tex = is_a(c); + + if (is_tex && is_exactly_a(exponent) && ex_to(exponent).is_negative()) { + + // Powers with negative numeric exponents are printed as fractions in TeX + c.s << "\\frac{1}{"; + power(basis, -exponent).eval().print(c); + c.s << "}"; + + } else if (exponent.is_equal(_ex1_2)) { + + // Square roots are printed in a special way + c.s << (is_tex ? "\\sqrt{" : "sqrt("); basis.print(c); - if (is_a(c)) - c.s << '}'; - else - c.s << ')'; + c.s << (is_tex ? '}' : ')'); + } else { - if (precedence() <= level) { - if (is_a(c)) - c.s << "{("; - else - c.s << "("; - } + + // Ordinary output of powers using '^' or '**' + if (precedence() <= level) + c.s << (is_tex ? "{(" : "("); basis.print(c, precedence()); - c.s << '^'; - if (is_a(c)) + if (is_a(c)) + c.s << "**"; + else + c.s << '^'; + if (is_tex) c.s << '{'; exponent.print(c, precedence()); - if (is_a(c)) + if (is_tex) c.s << '}'; - if (precedence() <= level) { - if (is_a(c)) - c.s << ")}"; - else - c.s << ')'; - } + if (precedence() <= level) + c.s << (is_tex ? ")}" : ")"); } } } @@ -240,49 +245,59 @@ ex power::map(map_function & f) const int power::degree(const ex & s) const { - if (is_ex_exactly_of_type(exponent, numeric) && ex_to(exponent).is_integer()) { + if (is_equal(ex_to(s))) + return 1; + else if (is_ex_exactly_of_type(exponent, numeric) && ex_to(exponent).is_integer()) { if (basis.is_equal(s)) return ex_to(exponent).to_int(); else return basis.degree(s) * ex_to(exponent).to_int(); - } - return 0; + } else if (basis.has(s)) + throw(std::runtime_error("power::degree(): undefined degree because of non-integer exponent")); + else + return 0; } int power::ldegree(const ex & s) const { - if (is_ex_exactly_of_type(exponent, numeric) && ex_to(exponent).is_integer()) { + if (is_equal(ex_to(s))) + return 1; + else if (is_ex_exactly_of_type(exponent, numeric) && ex_to(exponent).is_integer()) { if (basis.is_equal(s)) return ex_to(exponent).to_int(); else return basis.ldegree(s) * ex_to(exponent).to_int(); - } - return 0; + } 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 (!basis.is_equal(s)) { + if (is_equal(ex_to(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(); + return _ex0; } else { // basis equal to s if (is_ex_exactly_of_type(exponent, numeric) && ex_to(exponent).is_integer()) { // integer exponent int int_exp = ex_to(exponent).to_int(); if (n == int_exp) - return _ex1(); + return _ex1; else - return _ex0(); + return _ex0; } else { // non-integer exponents are treated as zero if (n == 0) return *this; else - return _ex0(); + return _ex0; } } } @@ -303,8 +318,6 @@ ex power::coeff(const ex & s, int n) const * @param level cut-off in recursive evaluation */ ex power::eval(int level) const { - debugmsg("power eval",LOGLEVEL_MEMBER_FUNCTION); - if ((level==1) && (flags & status_flags::evaluated)) return *this; else if (level == -max_recursion_level) @@ -332,11 +345,11 @@ ex power::eval(int level) const if (ebasis.is_zero()) throw (std::domain_error("power::eval(): pow(0,0) is undefined")); else - return _ex1(); + return _ex1; } // ^(x,1) -> x - if (eexponent.is_equal(_ex1())) + if (eexponent.is_equal(_ex1)) return ebasis; // ^(0,c1) -> 0 or exception (depending on real value of c1) @@ -346,12 +359,12 @@ ex power::eval(int level) const else if ((num_exponent->real()).is_negative()) throw (pole_error("power::eval(): division by zero",1)); else - return _ex0(); + return _ex0; } // ^(1,x) -> 1 - if (ebasis.is_equal(_ex1())) - return _ex1(); + if (ebasis.is_equal(_ex1)) + return _ex1; if (exponent_is_numerical) { @@ -420,7 +433,7 @@ ex power::eval(int level) const if (is_ex_exactly_of_type(sub_exponent,numeric)) { const numeric & num_sub_exponent = ex_to(sub_exponent); GINAC_ASSERT(num_sub_exponent!=numeric(1)); - if (num_exponent->is_integer() || (abs(num_sub_exponent) - _num1()).is_negative()) + if (num_exponent->is_integer() || (abs(num_sub_exponent) - _num1).is_negative()) return power(sub_basis,num_sub_exponent.mul(*num_exponent)); } } @@ -435,21 +448,21 @@ ex power::eval(int level) const if (is_ex_exactly_of_type(ebasis,mul)) { GINAC_ASSERT(!num_exponent->is_integer()); // should have been handled above const mul & mulref = ex_to(ebasis); - if (!mulref.overall_coeff.is_equal(_ex1())) { + if (!mulref.overall_coeff.is_equal(_ex1)) { const numeric & num_coeff = ex_to(mulref.overall_coeff); if (num_coeff.is_real()) { if (num_coeff.is_positive()) { mul *mulp = new mul(mulref); - mulp->overall_coeff = _ex1(); + mulp->overall_coeff = _ex1; 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())<0); - if (num_coeff.compare(_num_1())!=0) { + GINAC_ASSERT(num_coeff.compare(_num0)<0); + if (!num_coeff.is_equal(_num_1)) { mul *mulp = new mul(mulref); - mulp->overall_coeff = _ex_1(); + mulp->overall_coeff = _ex_1; mulp->clearflag(status_flags::evaluated); mulp->clearflag(status_flags::hash_calculated); return (new mul(power(*mulp,exponent), @@ -478,8 +491,6 @@ ex power::eval(int level) const ex power::evalf(int level) const { - debugmsg("power evalf",LOGLEVEL_MEMBER_FUNCTION); - ex ebasis; ex eexponent; @@ -490,7 +501,7 @@ ex power::evalf(int level) const throw(std::runtime_error("max recursion level reached")); } else { ebasis = basis.evalf(level-1); - if (!is_ex_exactly_of_type(exponent,numeric)) + if (!is_exactly_a(exponent)) eexponent = exponent.evalf(level-1); else eexponent = exponent; @@ -538,20 +549,20 @@ ex power::derivative(const symbol & s) const // 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())); + 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())))); + mul(mul(exponent, basis.diff(s)), power(basis, _ex_1)))); } } int power::compare_same_type(const basic & other) const { - GINAC_ASSERT(is_exactly_of_type(other, power)); + GINAC_ASSERT(is_exactly_a(other)); const power &o = static_cast(other); int cmpval = basis.compare(o.basis); @@ -645,89 +656,90 @@ ex power::expand(unsigned options) const // non-virtual functions in this class ////////// -/** expand a^n where a is an add and n is an integer. +/** 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) const { if (n==2) return expand_add_2(a); - - int m = a.nops(); - exvector sum; - sum.reserve((n+1)*(m-1)); + + const int m = a.nops(); + exvector result; + // The number of terms will be the number of combinatorial compositions, + // i.e. the number of unordered arrangement of m nonnegative integers + // which sum up to n. It is frequently written as C_n(m) and directly + // related with binomial coefficients: + result.reserve(binomial(numeric(n+m-1), numeric(m-1)).to_int()); 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(b).exponent,numeric) || + GINAC_ASSERT(!is_exactly_a(b)); + GINAC_ASSERT(!is_exactly_a(b) || + !is_exactly_a(ex_to(b).exponent) || !ex_to(ex_to(b).exponent).is_pos_integer() || - !is_ex_exactly_of_type(ex_to(b).basis,add) || - !is_ex_exactly_of_type(ex_to(b).basis,mul) || - !is_ex_exactly_of_type(ex_to(b).basis,power)); + !is_exactly_a(ex_to(b).basis) || + !is_exactly_a(ex_to(b).basis) || + !is_exactly_a(ex_to(b).basis)); if (is_ex_exactly_of_type(b,mul)) term.push_back(expand_mul(ex_to(b),numeric(k[l]))); else term.push_back(power(b,k[l])); } - + const ex & 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(b).exponent,numeric) || + GINAC_ASSERT(!is_exactly_a(b)); + GINAC_ASSERT(!is_exactly_a(b) || + !is_exactly_a(ex_to(b).exponent) || !ex_to(ex_to(b).exponent).is_pos_integer() || - !is_ex_exactly_of_type(ex_to(b).basis,add) || - !is_ex_exactly_of_type(ex_to(b).basis,mul) || - !is_ex_exactly_of_type(ex_to(b).basis,power)); + !is_exactly_a(ex_to(b).basis) || + !is_exactly_a(ex_to(b).basis) || + !is_exactly_a(ex_to(b).basis)); if (is_ex_exactly_of_type(b,mul)) term.push_back(expand_mul(ex_to(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; lsetflag(status_flags::dynallocated)); - + + result.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; + 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; isetflag(status_flags::dynallocated | - status_flags::expanded ); + + return (new add(result))->setflag(status_flags::dynallocated | + status_flags::expanded); } @@ -739,36 +751,36 @@ ex power::expand_add_2(const add & a) const 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) { const ex & r = cit0->rest; const ex & 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(r).exponent,numeric) || + GINAC_ASSERT(!is_exactly_a(r)); + GINAC_ASSERT(!is_exactly_a(r) || + !is_exactly_a(ex_to(r).exponent) || !ex_to(ex_to(r).exponent).is_pos_integer() || - !is_ex_exactly_of_type(ex_to(r).basis,add) || - !is_ex_exactly_of_type(ex_to(r).basis,mul) || - !is_ex_exactly_of_type(ex_to(r).basis,power)); + !is_exactly_a(ex_to(r).basis) || + !is_exactly_a(ex_to(r).basis) || + !is_exactly_a(ex_to(r).basis)); - if (are_ex_trivially_equal(c,_ex1())) { + if (are_ex_trivially_equal(c,_ex1)) { if (is_ex_exactly_of_type(r,mul)) { - sum.push_back(expair(expand_mul(ex_to(r),_num2()), - _ex1())); + sum.push_back(expair(expand_mul(ex_to(r),_num2), + _ex1)); } else { - sum.push_back(expair((new power(r,_ex2()))->setflag(status_flags::dynallocated), - _ex1())); + sum.push_back(expair((new power(r,_ex2))->setflag(status_flags::dynallocated), + _ex1)); } } else { if (is_ex_exactly_of_type(r,mul)) { - sum.push_back(expair(expand_mul(ex_to(r),_num2()), - ex_to(c).power_dyn(_num2()))); + sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to(r),_num2), + ex_to(c).power_dyn(_num2))); } else { - sum.push_back(expair((new power(r,_ex2()))->setflag(status_flags::dynallocated), - ex_to(c).power_dyn(_num2()))); + sum.push_back(a.combine_ex_with_coeff_to_pair((new power(r,_ex2))->setflag(status_flags::dynallocated), + ex_to(c).power_dyn(_num2))); } } @@ -776,7 +788,7 @@ ex power::expand_add_2(const add & a) const const ex & r1 = cit1->rest; const ex & c1 = cit1->coeff; sum.push_back(a.combine_ex_with_coeff_to_pair((new mul(r,r1))->setflag(status_flags::dynallocated), - _num2().mul(ex_to(c)).mul_dyn(ex_to(c1)))); + _num2.mul(ex_to(c)).mul_dyn(ex_to(c1)))); } } @@ -786,10 +798,10 @@ ex power::expand_add_2(const add & a) const 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(a.overall_coeff).mul_dyn(_num2()))); + sum.push_back(a.combine_pair_with_coeff_to_pair(*i, ex_to(a.overall_coeff).mul_dyn(_num2))); ++i; } - sum.push_back(expair(ex_to(a.overall_coeff).power_dyn(_num2()),_ex1())); + sum.push_back(expair(ex_to(a.overall_coeff).power_dyn(_num2),_ex1)); } GINAC_ASSERT(sum.size()==(a_nops*(a_nops+1))/2); @@ -797,35 +809,30 @@ ex power::expand_add_2(const add & a) const return (new add(sum))->setflag(status_flags::dynallocated | status_flags::expanded); } -/** Expand factors of m in m^n where m is a mul and n is and integer +/** Expand factors of m in m^n where m is a mul and n is and integer. * @see power::expand */ ex power::expand_mul(const mul & m, const numeric & n) const { + GINAC_ASSERT(n.is_integer()); + if (n.is_zero()) - return _ex1(); - + return _ex1; + 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)); + 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((*cit).coeff).mul(n))); + distrseq.push_back(expair(cit->rest, ex_to(cit->coeff).mul(n))); } ++cit; } - return (new mul(distrseq,ex_to(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated); -} - -// helper function - -ex sqrt(const ex & a) -{ - return power(a,_ex1_2()); + return (new mul(distrseq, ex_to(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated); } } // namespace GiNaC