]> www.ginac.de Git - ginac.git/blobdiff - ginac/inifcns.cpp
Update copyright statements.
[ginac.git] / ginac / inifcns.cpp
index 830b1bff41ff556816e6c398add542179ad6f7e2..02c909f313180456e7598794500cad82c4a0370f 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's initially known functions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2005 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2014 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
@@ -20,9 +20,6 @@
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
-#include <vector>
-#include <stdexcept>
-
 #include "inifcns.h"
 #include "ex.h"
 #include "constant.h"
@@ -37,6 +34,9 @@
 #include "symmetry.h"
 #include "utils.h"
 
+#include <stdexcept>
+#include <vector>
+
 namespace GiNaC {
 
 //////////
@@ -66,12 +66,152 @@ static ex conjugate_conjugate(const ex & arg)
        return arg;
 }
 
+static ex conjugate_real_part(const ex & arg)
+{
+       return arg.real_part();
+}
+
+static ex conjugate_imag_part(const ex & arg)
+{
+       return -arg.imag_part();
+}
+
+static bool func_arg_info(const ex & arg, unsigned inf)
+{
+       // for some functions we can return the info() of its argument
+       // (think of conjugate())
+       switch (inf) {
+               case info_flags::polynomial:
+               case info_flags::integer_polynomial:
+               case info_flags::cinteger_polynomial:
+               case info_flags::rational_polynomial:
+               case info_flags::real:
+               case info_flags::rational:
+               case info_flags::integer:
+               case info_flags::crational:
+               case info_flags::cinteger:
+               case info_flags::even:
+               case info_flags::odd:
+               case info_flags::prime:
+               case info_flags::crational_polynomial:
+               case info_flags::rational_function:
+               case info_flags::algebraic:
+               case info_flags::positive:
+               case info_flags::negative:
+               case info_flags::nonnegative:
+               case info_flags::posint:
+               case info_flags::negint:
+               case info_flags::nonnegint:
+               case info_flags::has_indices:
+                       return arg.info(inf);
+       }
+       return false;
+}
+
+static bool conjugate_info(const ex & arg, unsigned inf)
+{
+       return func_arg_info(arg, inf);
+}
+
 REGISTER_FUNCTION(conjugate_function, eval_func(conjugate_eval).
                                       evalf_func(conjugate_evalf).
+                                      info_func(conjugate_info).
                                       print_func<print_latex>(conjugate_print_latex).
                                       conjugate_func(conjugate_conjugate).
+                                      real_part_func(conjugate_real_part).
+                                      imag_part_func(conjugate_imag_part).
                                       set_name("conjugate","conjugate"));
 
+//////////
+// real part
+//////////
+
+static ex real_part_evalf(const ex & arg)
+{
+       if (is_exactly_a<numeric>(arg)) {
+               return ex_to<numeric>(arg).real();
+       }
+       return real_part_function(arg).hold();
+}
+
+static ex real_part_eval(const ex & arg)
+{
+       return arg.real_part();
+}
+
+static void real_part_print_latex(const ex & arg, const print_context & c)
+{
+       c.s << "\\Re"; arg.print(c); c.s << "";
+}
+
+static ex real_part_conjugate(const ex & arg)
+{
+       return real_part_function(arg).hold();
+}
+
+static ex real_part_real_part(const ex & arg)
+{
+       return real_part_function(arg).hold();
+}
+
+static ex real_part_imag_part(const ex & arg)
+{
+       return 0;
+}
+
+REGISTER_FUNCTION(real_part_function, eval_func(real_part_eval).
+                                      evalf_func(real_part_evalf).
+                                      print_func<print_latex>(real_part_print_latex).
+                                      conjugate_func(real_part_conjugate).
+                                      real_part_func(real_part_real_part).
+                                      imag_part_func(real_part_imag_part).
+                                      set_name("real_part","real_part"));
+
+//////////
+// imag part
+//////////
+
+static ex imag_part_evalf(const ex & arg)
+{
+       if (is_exactly_a<numeric>(arg)) {
+               return ex_to<numeric>(arg).imag();
+       }
+       return imag_part_function(arg).hold();
+}
+
+static ex imag_part_eval(const ex & arg)
+{
+       return arg.imag_part();
+}
+
+static void imag_part_print_latex(const ex & arg, const print_context & c)
+{
+       c.s << "\\Im"; arg.print(c); c.s << "";
+}
+
+static ex imag_part_conjugate(const ex & arg)
+{
+       return imag_part_function(arg).hold();
+}
+
+static ex imag_part_real_part(const ex & arg)
+{
+       return imag_part_function(arg).hold();
+}
+
+static ex imag_part_imag_part(const ex & arg)
+{
+       return 0;
+}
+
+REGISTER_FUNCTION(imag_part_function, eval_func(imag_part_eval).
+                                      evalf_func(imag_part_evalf).
+                                      print_func<print_latex>(imag_part_print_latex).
+                                      conjugate_func(imag_part_conjugate).
+                                      real_part_func(imag_part_real_part).
+                                      imag_part_func(imag_part_imag_part).
+                                      set_name("imag_part","imag_part"));
+
 //////////
 // absolute value
 //////////
@@ -88,6 +228,49 @@ static ex abs_eval(const ex & arg)
 {
        if (is_exactly_a<numeric>(arg))
                return abs(ex_to<numeric>(arg));
+
+       if (arg.info(info_flags::nonnegative))
+               return arg;
+
+       if (is_ex_the_function(arg, abs))
+               return arg;
+
+       if (is_ex_the_function(arg, exp))
+               return exp(arg.op(0).real_part());
+
+       if (is_exactly_a<power>(arg)) {
+               const ex& base = arg.op(0);
+               const ex& exponent = arg.op(1);
+               if (base.info(info_flags::positive) || exponent.info(info_flags::real))
+                       return pow(abs(base), exponent.real_part());
+       }
+
+       if (is_ex_the_function(arg, conjugate_function))
+               return abs(arg.op(0));
+
+       if (is_ex_the_function(arg, step))
+               return arg;
+
+       return abs(arg).hold();
+}
+
+static ex abs_expand(const ex & arg, unsigned options)
+{
+       if ((options & expand_options::expand_transcendental)
+               && is_exactly_a<mul>(arg)) {
+               exvector prodseq;
+               prodseq.reserve(arg.nops());
+               for (const_iterator i = arg.begin(); i != arg.end(); ++i) {
+                       if (options & expand_options::expand_function_args)
+                               prodseq.push_back(abs(i->expand(options)));
+                       else
+                               prodseq.push_back(abs(*i));
+               }
+               return (new mul(prodseq))->setflag(status_flags::dynallocated | status_flags::expanded);
+       }
+
+       if (options & expand_options::expand_function_args)
+               return abs(arg.expand(options)).hold();
        else
                return abs(arg).hold();
 }
@@ -104,23 +287,65 @@ static void abs_print_csrc_float(const ex & arg, const print_context & c)
 
 static ex abs_conjugate(const ex & arg)
 {
-       return abs(arg);
+       return abs(arg).hold();
+}
+
+static ex abs_real_part(const ex & arg)
+{
+       return abs(arg).hold();
+}
+
+static ex abs_imag_part(const ex& arg)
+{
+       return 0;
 }
 
 static ex abs_power(const ex & arg, const ex & exp)
 {
-       if (arg.is_equal(arg.conjugate()) && is_a<numeric>(exp) && ex_to<numeric>(exp).is_even())
+       if (arg.is_equal(arg.conjugate()) && ((is_a<numeric>(exp) && ex_to<numeric>(exp).is_even())
+                                               || exp.info(info_flags::even)))
                return power(arg, exp);
        else
                return power(abs(arg), exp).hold();
 }
 
+bool abs_info(const ex & arg, unsigned inf)
+{
+       switch (inf) {
+               case info_flags::integer:
+               case info_flags::even:
+               case info_flags::odd:
+               case info_flags::prime:
+                       return arg.info(inf);
+               case info_flags::nonnegint:
+                       return arg.info(info_flags::integer);
+               case info_flags::nonnegative:
+               case info_flags::real:
+                       return true;
+               case info_flags::negative:
+                       return false;
+               case info_flags::positive:
+                       return arg.info(info_flags::positive) || arg.info(info_flags::negative);
+               case info_flags::has_indices: {
+                       if (arg.info(info_flags::has_indices))
+                               return true;
+                       else
+                               return false;
+               }
+       }
+       return false;
+}
+
 REGISTER_FUNCTION(abs, eval_func(abs_eval).
                        evalf_func(abs_evalf).
+                       expand_func(abs_expand).
+                       info_func(abs_info).
                        print_func<print_latex>(abs_print_latex).
                        print_func<print_csrc_float>(abs_print_csrc_float).
                        print_func<print_csrc_double>(abs_print_csrc_float).
                        conjugate_func(abs_conjugate).
+                       real_part_func(abs_real_part).
+                       imag_part_func(abs_imag_part).
                        power_func(abs_power));
 
 //////////
@@ -180,24 +405,27 @@ static ex step_series(const ex & arg,
        return pseries(rel,seq);
 }
 
-static ex step_power(const ex & arg, const ex & exp)
+static ex step_conjugate(const ex& arg)
 {
-       if (exp.info(info_flags::positive))
-               return step(arg);
-       
-       return power(step(arg), exp).hold();
+       return step(arg).hold();
 }
 
-static ex step_conjugate(const ex& arg)
+static ex step_real_part(const ex& arg)
+{
+       return step(arg).hold();
+}
+
+static ex step_imag_part(const ex& arg)
 {
-       return step(arg);
+       return 0;
 }
 
 REGISTER_FUNCTION(step, eval_func(step_eval).
                         evalf_func(step_evalf).
                         series_func(step_series).
                         conjugate_func(step_conjugate).
-                        power_func(step_power));
+                        real_part_func(step_real_part).
+                        imag_part_func(step_imag_part));
 
 //////////
 // Complex sign
@@ -258,13 +486,38 @@ static ex csgn_series(const ex & arg,
 
 static ex csgn_conjugate(const ex& arg)
 {
-       return csgn(arg);
+       return csgn(arg).hold();
+}
+
+static ex csgn_real_part(const ex& arg)
+{
+       return csgn(arg).hold();
+}
+
+static ex csgn_imag_part(const ex& arg)
+{
+       return 0;
+}
+
+static ex csgn_power(const ex & arg, const ex & exp)
+{
+       if (is_a<numeric>(exp) && exp.info(info_flags::positive) && ex_to<numeric>(exp).is_integer()) {
+               if (ex_to<numeric>(exp).is_odd())
+                       return csgn(arg).hold();
+               else
+                       return power(csgn(arg), _ex2).hold();
+       } else
+               return power(csgn(arg), exp).hold();
 }
 
+
 REGISTER_FUNCTION(csgn, eval_func(csgn_eval).
                         evalf_func(csgn_evalf).
                         series_func(csgn_series).
-                        conjugate_func(csgn_conjugate));
+                        conjugate_func(csgn_conjugate).
+                        real_part_func(csgn_real_part).
+                        imag_part_func(csgn_imag_part).
+                        power_func(csgn_power));
 
 
 //////////
@@ -341,7 +594,17 @@ static ex eta_series(const ex & x, const ex & y,
 
 static ex eta_conjugate(const ex & x, const ex & y)
 {
-       return -eta(x,y);
+       return -eta(x, y).hold();
+}
+
+static ex eta_real_part(const ex & x, const ex & y)
+{
+       return 0;
+}
+
+static ex eta_imag_part(const ex & x, const ex & y)
+{
+       return -I*eta(x, y).hold();
 }
 
 REGISTER_FUNCTION(eta, eval_func(eta_eval).
@@ -349,7 +612,9 @@ REGISTER_FUNCTION(eta, eval_func(eta_eval).
                        series_func(eta_series).
                        latex_name("\\eta").
                        set_symmetry(sy_symm(0, 1)).
-                       conjugate_func(eta_conjugate));
+                       conjugate_func(eta_conjugate).
+                       real_part_func(eta_real_part).
+                       imag_part_func(eta_imag_part));
 
 
 //////////
@@ -483,11 +748,26 @@ static ex Li2_series(const ex &x, const relational &rel, int order, unsigned opt
        throw do_taylor();  // caught by function::series()
 }
 
+static ex Li2_conjugate(const ex & x)
+{
+       // conjugate(Li2(x))==Li2(conjugate(x)) unless on the branch cuts which
+       // run along the positive real axis beginning at 1.
+       if (x.info(info_flags::negative)) {
+               return Li2(x).hold();
+       }
+       if (is_exactly_a<numeric>(x) &&
+           (!x.imag_part().is_zero() || x < *_num1_p)) {
+               return Li2(x.conjugate());
+       }
+       return conjugate_function(Li2(x)).hold();
+}
+
 REGISTER_FUNCTION(Li2, eval_func(Li2_eval).
                        evalf_func(Li2_evalf).
                        derivative_func(Li2_deriv).
                        series_func(Li2_series).
-                       latex_name("\\mbox{Li}_2"));
+                       conjugate_func(Li2_conjugate).
+                       latex_name("\\mathrm{Li}_2"));
 
 //////////
 // trilogarithm
@@ -501,7 +781,7 @@ static ex Li3_eval(const ex & x)
 }
 
 REGISTER_FUNCTION(Li3, eval_func(Li3_eval).
-                       latex_name("\\mbox{Li}_3"));
+                       latex_name("\\mathrm{Li}_3"));
 
 //////////
 // Derivatives of Riemann's Zeta-function  zetaderiv(0,x)==zeta(x)
@@ -512,7 +792,7 @@ static ex zetaderiv_eval(const ex & n, const ex & x)
        if (n.info(info_flags::numeric)) {
                // zetaderiv(0,x) -> zeta(x)
                if (n.is_zero())
-                       return zeta(x);
+                       return zeta(x).hold();
        }
        
        return zetaderiv(n, x).hold();
@@ -564,14 +844,26 @@ static void factorial_print_dflt_latex(const ex & x, const print_context & c)
 
 static ex factorial_conjugate(const ex & x)
 {
-       return factorial(x);
+       return factorial(x).hold();
+}
+
+static ex factorial_real_part(const ex & x)
+{
+       return factorial(x).hold();
+}
+
+static ex factorial_imag_part(const ex & x)
+{
+       return 0;
 }
 
 REGISTER_FUNCTION(factorial, eval_func(factorial_eval).
                              evalf_func(factorial_evalf).
                              print_func<print_dflt>(factorial_print_dflt_latex).
                              print_func<print_latex>(factorial_print_dflt_latex).
-                             conjugate_func(factorial_conjugate));
+                             conjugate_func(factorial_conjugate).
+                             real_part_func(factorial_real_part).
+                             imag_part_func(factorial_imag_part));
 
 //////////
 // binomial
@@ -587,7 +879,7 @@ static ex binomial_sym(const ex & x, const numeric & y)
        if (y.is_integer()) {
                if (y.is_nonneg_integer()) {
                        const unsigned N = y.to_int();
-                       if (N == 0) return _ex0;
+                       if (N == 0) return _ex1;
                        if (N == 1) return x;
                        ex t = x.expand();
                        for (unsigned i = 2; i <= N; ++i)
@@ -616,12 +908,24 @@ static ex binomial_eval(const ex & x, const ex &y)
 // function, also complex conjugation should be changed (or rather, deleted).
 static ex binomial_conjugate(const ex & x, const ex & y)
 {
-       return binomial(x,y);
+       return binomial(x,y).hold();
+}
+
+static ex binomial_real_part(const ex & x, const ex & y)
+{
+       return binomial(x,y).hold();
+}
+
+static ex binomial_imag_part(const ex & x, const ex & y)
+{
+       return 0;
 }
 
 REGISTER_FUNCTION(binomial, eval_func(binomial_eval).
                             evalf_func(binomial_evalf).
-                            conjugate_func(binomial_conjugate));
+                            conjugate_func(binomial_conjugate).
+                            real_part_func(binomial_real_part).
+                            imag_part_func(binomial_imag_part));
 
 //////////
 // Order term function (for truncated power series)
@@ -656,7 +960,19 @@ static ex Order_series(const ex & x, const relational & r, int order, unsigned o
 
 static ex Order_conjugate(const ex & x)
 {
-       return Order(x);
+       return Order(x).hold();
+}
+
+static ex Order_real_part(const ex & x)
+{
+       return Order(x).hold();
+}
+
+static ex Order_imag_part(const ex & x)
+{
+       if(x.info(info_flags::real))
+               return 0;
+       return Order(x).hold();
 }
 
 // Differentiation is handled in function::derivative because of its special requirements
@@ -664,7 +980,9 @@ static ex Order_conjugate(const ex & x)
 REGISTER_FUNCTION(Order, eval_func(Order_eval).
                          series_func(Order_series).
                          latex_name("\\mathcal{O}").
-                         conjugate_func(Order_conjugate));
+                         conjugate_func(Order_conjugate).
+                         real_part_func(Order_real_part).
+                         imag_part_func(Order_imag_part));
 
 //////////
 // Solve linear system
@@ -686,7 +1004,7 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
        
        // syntax checks
        if (!eqns.info(info_flags::list)) {
-               throw(std::invalid_argument("lsolve(): 1st argument must be a list"));
+               throw(std::invalid_argument("lsolve(): 1st argument must be a list or an equation"));
        }
        for (size_t i=0; i<eqns.nops(); i++) {
                if (!eqns.op(i).info(info_flags::relation_equal)) {
@@ -694,7 +1012,7 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
                }
        }
        if (!symbols.info(info_flags::list)) {
-               throw(std::invalid_argument("lsolve(): 2nd argument must be a list"));
+               throw(std::invalid_argument("lsolve(): 2nd argument must be a list or a symbol"));
        }
        for (size_t i=0; i<symbols.nops(); i++) {
                if (!symbols.op(i).info(info_flags::symbol)) {
@@ -794,9 +1112,24 @@ fsolve(const ex& f_in, const symbol& x, const numeric& x1, const numeric& x2)
        do {
                xxprev = xx[side];
                fxprev = fx[side];
-               xx[side] += ex_to<numeric>(ff.subs(x==xx[side]).evalf());
-               fx[side] = ex_to<numeric>(f.subs(x==xx[side]).evalf());
-               if ((side==0 && xx[0]<xxprev) || (side==1 && xx[1]>xxprev) || xx[0]>xx[1]) {
+               ex dx_ = ff.subs(x == xx[side]).evalf();
+               if (!is_a<numeric>(dx_))
+                       throw std::runtime_error("fsolve(): function derivative does not evaluate numerically");
+               xx[side] += ex_to<numeric>(dx_);
+               // Now check if Newton-Raphson method shot out of the interval 
+               bool bad_shot = (side == 0 && xx[0] < xxprev) || 
+                               (side == 1 && xx[1] > xxprev) || xx[0] > xx[1];
+               if (!bad_shot) {
+                       // Compute f(x) only if new x is inside the interval.
+                       // The function might be difficult to compute numerically
+                       // or even ill defined outside the interval. Also it's
+                       // a small optimization. 
+                       ex f_x = f.subs(x == xx[side]).evalf();
+                       if (!is_a<numeric>(f_x))
+                               throw std::runtime_error("fsolve(): function does not evaluate numerically");
+                       fx[side] = ex_to<numeric>(f_x);
+               }
+               if (bad_shot) {
                        // Oops, Newton-Raphson method shot out of the interval.
                        // Restore, and try again with the other side instead!
                        xx[side] = xxprev;
@@ -804,8 +1137,16 @@ fsolve(const ex& f_in, const symbol& x, const numeric& x1, const numeric& x2)
                        side = !side;
                        xxprev = xx[side];
                        fxprev = fx[side];
-                       xx[side] += ex_to<numeric>(ff.subs(x==xx[side]).evalf());
-                       fx[side] = ex_to<numeric>(f.subs(x==xx[side]).evalf());
+
+                       ex dx_ = ff.subs(x == xx[side]).evalf();
+                       if (!is_a<numeric>(dx_))
+                               throw std::runtime_error("fsolve(): function derivative does not evaluate numerically [2]");
+                       xx[side] += ex_to<numeric>(dx_);
+
+                       ex f_x = f.subs(x==xx[side]).evalf();
+                       if (!is_a<numeric>(f_x))
+                               throw std::runtime_error("fsolve(): function does not evaluate numerically [2]");
+                       fx[side] = ex_to<numeric>(f_x);
                }
                if ((fx[side]<0 && fx[!side]<0) || (fx[side]>0 && fx[!side]>0)) {
                        // Oops, the root isn't bracketed any more.
@@ -829,7 +1170,10 @@ fsolve(const ex& f_in, const symbol& x, const numeric& x1, const numeric& x2)
                        static const double secant_weight = 0.984375;  // == 63/64 < 1
                        numeric xxmid = (1-secant_weight)*0.5*(xx[0]+xx[1])
                            + secant_weight*(xx[0]+fx[0]*(xx[0]-xx[1])/(fx[1]-fx[0]));
-                       numeric fxmid = ex_to<numeric>(f.subs(x==xxmid).evalf());
+                       ex fxmid_ = f.subs(x == xxmid).evalf();
+                       if (!is_a<numeric>(fxmid_))
+                               throw std::runtime_error("fsolve(): function does not evaluate numerically [3]");
+                       numeric fxmid = ex_to<numeric>(fxmid_);
                        if (fxmid.is_zero()) {
                                // Luck strikes...
                                return xxmid;