]> www.ginac.de Git - ginac.git/blobdiff - ginac/power.cpp
Added a document about the coding conventions used in GiNaC. Corrections,
[ginac.git] / ginac / power.cpp
index 85e5bd6c9a92e76c470dc83c527a4d6eaa85a0d0..b38b733cb575667e0047fdad10383ccd3b53af0d 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
 
 /*
- *  GiNaC Copyright (C) 1999-2002 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
@@ -23,6 +23,7 @@
 #include <vector>
 #include <iostream>
 #include <stdexcept>
+#include <limits>
 
 #include "power.h"
 #include "expairseq.h"
 #include "ncmul.h"
 #include "numeric.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 "print.h"
+#include "lst.h"
 #include "archive.h"
 #include "utils.h"
 
 namespace GiNaC {
 
-GINAC_IMPLEMENT_REGISTERED_CLASS(power, basic)
+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))
 
 typedef std::vector<int> intvector;
 
 //////////
-// default ctor, dtor, copy ctor, assignment operator and helpers
+// default constructor
 //////////
 
 power::power() : inherited(TINFO_power) { }
 
-void power::copy(const power & other)
-{
-       inherited::copy(other);
-       basis = other.basis;
-       exponent = other.exponent;
-}
-
-DEFAULT_DESTROY(power)
-
 //////////
-// other ctors
+// other constructors
 //////////
 
 // all inlined
@@ -70,7 +68,7 @@ DEFAULT_DESTROY(power)
 // archiving
 //////////
 
-power::power(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+power::power(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
        n.find_ex("basis", basis, sym_lst);
        n.find_ex("exponent", exponent, sym_lst);
@@ -91,11 +89,58 @@ DEFAULT_UNARCHIVE(power)
 
 // public
 
+void power::print_power(const print_context & c, const char *powersymbol, const char *openbrace, const char *closebrace, unsigned level) const
+{
+       // 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;
+}
+
+void power::do_print_dflt(const print_dflt & c, unsigned level) const
+{
+       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);
+}
+
+void power::do_print_latex(const print_latex & c, unsigned level) const
+{
+       if (is_exactly_a<numeric>(exponent) && ex_to<numeric>(exponent).is_negative()) {
+
+               // Powers with negative numeric exponents are printed as fractions
+               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 << "\\sqrt{";
+               basis.print(c);
+               c.s << '}';
+
+       } else
+               print_power(c, "^", "{", "}", level);
+}
+
 static void print_sym_pow(const print_context & c, const symbol &x, int exp)
 {
        // 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 parenthisation is really necessary.
+       // to learn why such a parenthesation is really necessary.
        if (exp == 1) {
                x.print(c);
        } else if (exp == 2) {
@@ -115,84 +160,58 @@ static void print_sym_pow(const print_context & c, const symbol &x, int exp)
        }
 }
 
-void power::print(const print_context & c, unsigned level) const
+void power::do_print_csrc(const print_csrc & c, unsigned level) const
 {
-       if (is_a<print_tree>(c)) {
-
-               inherited::print(c, level);
-
-       } else if (is_a<print_csrc>(c)) {
-
-               // Integer powers of symbols are printed in a special, optimized way
-               if (exponent.info(info_flags::integer)
-                && (is_exactly_a<symbol>(basis) || is_exactly_a<constant>(basis))) {
-                       int exp = ex_to<numeric>(exponent).to_int();
-                       if (exp > 0)
-                               c.s << '(';
-                       else {
-                               exp = -exp;
-                               if (is_a<print_csrc_cl_N>(c))
-                                       c.s << "recip(";
-                               else
-                                       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)) {
+       // 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;
                        if (is_a<print_csrc_cl_N>(c))
                                c.s << "recip(";
                        else
                                c.s << "1.0/(";
-                       basis.print(c);
-                       c.s << ')';
-
-               // Otherwise, use the pow() or expt() (CLN) functions
-               } else {
-                       if (is_a<print_csrc_cl_N>(c))
-                               c.s << "expt(";
-                       else
-                               c.s << "pow(";
-                       basis.print(c);
-                       c.s << ',';
-                       exponent.print(c);
-                       c.s << ')';
                }
+               print_sym_pow(c, ex_to<symbol>(basis), exp);
+               c.s << ')';
 
-       } else if (is_a<print_python_repr>(c)) {
+       // <expr>^-1 is printed as "1.0/<expr>" or with the recip() function of CLN
+       } else if (exponent.is_equal(_ex_1)) {
+               if (is_a<print_csrc_cl_N>(c))
+                       c.s << "recip(";
+               else
+                       c.s << "1.0/(";
+               basis.print(c);
+               c.s << ')';
 
-               c.s << class_name() << '(';
+       // Otherwise, use the pow() or expt() (CLN) functions
+       } else {
+               if (is_a<print_csrc_cl_N>(c))
+                       c.s << "expt(";
+               else
+                       c.s << "pow(";
                basis.print(c);
                c.s << ',';
                exponent.print(c);
                c.s << ')';
+       }
+}
 
-       } else {
-
-               bool is_tex = is_a<print_latex>(c);
+void power::do_print_python(const print_python & c, unsigned level) const
+{
+       print_power(c, "**", "", "", level);
+}
 
-               if (exponent.is_equal(_ex1_2)) {
-                       c.s << (is_tex ? "\\sqrt{" : "sqrt(");
-                       basis.print(c);
-                       c.s << (is_tex ? '}' : ')');
-               } else {
-                       if (precedence() <= level)
-                               c.s << (is_tex ? "{(" : "(");
-                       basis.print(c, precedence());
-                       if (is_a<print_python>(c))
-                               c.s << "**";
-                       else
-                               c.s << '^';
-                       if (is_tex)
-                               c.s << '{';
-                       exponent.print(c, precedence());
-                       if (is_tex)
-                               c.s << '}';
-                       if (precedence() <= level)
-                               c.s << (is_tex ? ")}" : ")");
-               }
-       }
+void power::do_print_python_repr(const print_python_repr & c, unsigned level) const
+{
+       c.s << class_name() << '(';
+       basis.print(c);
+       c.s << ',';
+       exponent.print(c);
+       c.s << ')';
 }
 
 bool power::info(unsigned inf) const
@@ -213,14 +232,13 @@ bool power::info(unsigned inf) const
        return inherited::info(inf);
 }
 
-unsigned power::nops() const
+size_t power::nops() const
 {
        return 2;
 }
 
-ex & power::let_op(int i)
+ex power::op(size_t i) const
 {
-       GINAC_ASSERT(i>=0);
        GINAC_ASSERT(i<2);
 
        return i==0 ? basis : exponent;
@@ -235,7 +253,7 @@ int power::degree(const ex & s) const
 {
        if (is_equal(ex_to<basic>(s)))
                return 1;
-       else if (is_ex_exactly_of_type(exponent, numeric) && ex_to<numeric>(exponent).is_integer()) {
+       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
@@ -250,7 +268,7 @@ int power::ldegree(const ex & s) const
 {
        if (is_equal(ex_to<basic>(s)))
                return 1;
-       else if (is_ex_exactly_of_type(exponent, numeric) && ex_to<numeric>(exponent).is_integer()) {
+       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
@@ -273,7 +291,7 @@ ex power::coeff(const ex & s, int n) const
                        return _ex0;
        } else {
                // basis equal to s
-               if (is_ex_exactly_of_type(exponent, numeric) && ex_to<numeric>(exponent).is_integer()) {
+               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)
@@ -319,11 +337,11 @@ ex power::eval(int level) const
        const numeric *num_basis;
        const numeric *num_exponent;
        
-       if (is_ex_exactly_of_type(ebasis, numeric)) {
+       if (is_exactly_a<numeric>(ebasis)) {
                basis_is_numerical = true;
                num_basis = &ex_to<numeric>(ebasis);
        }
-       if (is_ex_exactly_of_type(eexponent, numeric)) {
+       if (is_exactly_a<numeric>(eexponent)) {
                exponent_is_numerical = true;
                num_exponent = &ex_to<numeric>(eexponent);
        }
@@ -414,11 +432,11 @@ ex power::eval(int level) const
                // ^(^(x,c1),c2) -> ^(x,c1*c2)
                // (c1, c2 numeric(), c2 integer or -1 < c1 <= 1,
                // case c1==1 should not happen, see below!)
-               if (is_ex_exactly_of_type(ebasis,power)) {
+               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_ex_exactly_of_type(sub_exponent,numeric)) {
+                       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).is_negative())
@@ -427,13 +445,13 @@ ex power::eval(int level) const
                }
        
                // ^(*(x,y,z),c1) -> *(x^c1,y^c1,z^c1) (c1 integer)
-               if (num_exponent->is_integer() && is_ex_exactly_of_type(ebasis,mul)) {
+               if (num_exponent->is_integer() && is_exactly_a<mul>(ebasis)) {
                        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 (is_ex_exactly_of_type(ebasis,mul)) {
+               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)) {
@@ -464,7 +482,7 @@ ex power::eval(int level) const
                // ^(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_ex_of_type(ebasis,matrix)) {
+                   !is_a<matrix>(ebasis)) {
                        return ncmul(exvector(num_exponent->to_int(), ebasis), true);
                }
        }
@@ -498,33 +516,46 @@ ex power::evalf(int level) const
        return power(ebasis,eexponent);
 }
 
-ex power::evalm(void) const
+ex power::evalm() const
 {
        const ex ebasis = basis.evalm();
        const ex eexponent = exponent.evalm();
-       if (is_ex_of_type(ebasis,matrix)) {
-               if (is_ex_of_type(eexponent,numeric)) {
+       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);
 }
 
-ex power::subs(const lst & ls, const lst & lr, bool no_pattern) const
-{
-       const ex &subsed_basis = basis.subs(ls, lr, no_pattern);
-       const ex &subsed_exponent = exponent.subs(ls, lr, no_pattern);
+// from mul.cpp
+extern bool tryfactsubs(const ex &, const ex &, int &, lst &);
 
-       if (are_ex_trivially_equal(basis, subsed_basis)
-        && are_ex_trivially_equal(exponent, subsed_exponent))
-               return basic::subs(ls, lr, no_pattern);
-       else
-               return power(subsed_basis, subsed_exponent).basic::subs(ls, lr, no_pattern);
+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();
+               lst repls;
+               if (tryfactsubs(*this, it->first, nummatches, repls))
+                       return (ex_to<basic>((*this) * power(it->second.subs(ex(repls), subs_options::no_pattern) / it->first.subs(ex(repls), subs_options::no_pattern), nummatches))).subs_one_level(m, options);
+       }
+
+       return subs_one_level(m, options);
 }
 
-ex power::simplify_ncmul(const exvector & v) const
+ex power::eval_ncmul(const exvector & v) const
 {
-       return inherited::simplify_ncmul(v);
+       return inherited::eval_ncmul(v);
 }
 
 // protected
@@ -560,12 +591,12 @@ int power::compare_same_type(const basic & other) const
                return exponent.compare(o.exponent);
 }
 
-unsigned power::return_type(void) const
+unsigned power::return_type() const
 {
        return basis.return_type();
 }
    
-unsigned power::return_type_tinfo(void) const
+unsigned power::return_type_tinfo() const
 {
        return basis.return_type_tinfo();
 }
@@ -579,7 +610,7 @@ ex power::expand(unsigned options) const
        const ex expanded_exponent = exponent.expand(options);
        
        // x^(a+b) -> x^a * x^b
-       if (is_ex_exactly_of_type(expanded_exponent, add)) {
+       if (is_exactly_a<add>(expanded_exponent)) {
                const add &a = ex_to<add>(expanded_exponent);
                exvector distrseq;
                distrseq.reserve(a.seq.size() + 1);
@@ -594,7 +625,7 @@ ex power::expand(unsigned options) const
                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_ex_exactly_of_type(expanded_basis, add))
+                       if (int_exponent > 0 && is_exactly_a<add>(expanded_basis))
                                distrseq.push_back(expand_add(ex_to<add>(expanded_basis), int_exponent));
                        else
                                distrseq.push_back(power(expanded_basis, a.overall_coeff));
@@ -606,7 +637,7 @@ ex power::expand(unsigned options) const
                return r.expand();
        }
        
-       if (!is_ex_exactly_of_type(expanded_exponent, numeric) ||
+       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();
@@ -620,11 +651,11 @@ ex power::expand(unsigned options) const
        int int_exponent = num_exponent.to_int();
        
        // (x+y)^n, n>0
-       if (int_exponent > 0 && is_ex_exactly_of_type(expanded_basis,add))
+       if (int_exponent > 0 && is_exactly_a<add>(expanded_basis))
                return expand_add(ex_to<add>(expanded_basis), int_exponent);
        
        // (x*y)^n -> x^n * y^n
-       if (is_ex_exactly_of_type(expanded_basis,mul))
+       if (is_exactly_a<mul>(expanded_basis))
                return expand_mul(ex_to<mul>(expanded_basis), num_exponent);
        
        // cannot expand further
@@ -651,7 +682,7 @@ ex power::expand_add(const add & a, int n) const
        if (n==2)
                return expand_add_2(a);
 
-       const int m = a.nops();
+       const size_t 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
@@ -663,7 +694,7 @@ ex power::expand_add(const add & a, int n) const
        intvector upper_limit(m-1);
        int l;
 
-       for (int l=0; l<m-1; ++l) {
+       for (size_t l=0; l<m-1; ++l) {
                k[l] = 0;
                k_cum[l] = 0;
                upper_limit[l] = n;
@@ -681,7 +712,7 @@ ex power::expand_add(const add & a, int n) const
                                     !is_exactly_a<add>(ex_to<power>(b).basis) ||
                                     !is_exactly_a<mul>(ex_to<power>(b).basis) ||
                                     !is_exactly_a<power>(ex_to<power>(b).basis));
-                       if (is_ex_exactly_of_type(b,mul))
+                       if (is_exactly_a<mul>(b))
                                term.push_back(expand_mul(ex_to<mul>(b),numeric(k[l])));
                        else
                                term.push_back(power(b,k[l]));
@@ -695,7 +726,7 @@ ex power::expand_add(const add & a, int n) const
                             !is_exactly_a<add>(ex_to<power>(b).basis) ||
                             !is_exactly_a<mul>(ex_to<power>(b).basis) ||
                             !is_exactly_a<power>(ex_to<power>(b).basis));
-               if (is_ex_exactly_of_type(b,mul))
+               if (is_exactly_a<mul>(b))
                        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]));
@@ -719,10 +750,10 @@ ex power::expand_add(const add & a, int n) const
                // recalc k_cum[] and upper_limit[]
                k_cum[l] = (l==0 ? k[0] : k_cum[l-1]+k[l]);
 
-               for (int i=l+1; i<m-1; ++i)
+               for (size_t 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)
+               for (size_t i=l+1; i<m-1; ++i)
                        upper_limit[i] = n-k_cum[i-1];
        }
 
@@ -736,7 +767,7 @@ ex power::expand_add(const add & a, int n) const
 ex power::expand_add_2(const add & a) const
 {
        epvector sum;
-       unsigned a_nops = a.nops();
+       size_t a_nops = a.nops();
        sum.reserve((a_nops*(a_nops+1))/2);
        epvector::const_iterator last = a.seq.end();
 
@@ -754,8 +785,8 @@ ex power::expand_add_2(const add & a) const
                             !is_exactly_a<mul>(ex_to<power>(r).basis) ||
                             !is_exactly_a<power>(ex_to<power>(r).basis));
                
-               if (are_ex_trivially_equal(c,_ex1)) {
-                       if (is_ex_exactly_of_type(r,mul)) {
+               if (c.is_equal(_ex1)) {
+                       if (is_exactly_a<mul>(r)) {
                                sum.push_back(expair(expand_mul(ex_to<mul>(r),_num2),
                                                     _ex1));
                        } else {
@@ -763,7 +794,7 @@ ex power::expand_add_2(const add & a) const
                                                     _ex1));
                        }
                } else {
-                       if (is_ex_exactly_of_type(r,mul)) {
+                       if (is_exactly_a<mul>(r)) {
                                sum.push_back(a.combine_ex_with_coeff_to_pair(expand_mul(ex_to<mul>(r),_num2),
                                                     ex_to<numeric>(c).power_dyn(_num2)));
                        } else {
@@ -771,7 +802,7 @@ ex power::expand_add_2(const add & a) const
                                                     ex_to<numeric>(c).power_dyn(_num2)));
                        }
                }
-                       
+
                for (epvector::const_iterator cit1=cit0+1; cit1!=last; ++cit1) {
                        const ex & r1 = cit1->rest;
                        const ex & c1 = cit1->coeff;
@@ -811,7 +842,7 @@ ex power::expand_mul(const mul & m, const numeric & n) const
        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)) {
+               if (is_exactly_a<numeric>(cit->rest)) {
                        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()