]> www.ginac.de Git - ginac.git/blobdiff - ginac/inifcns_trans.cpp
Fixed a bug in atan2. It gave a division by zero error for calls like
[ginac.git] / ginac / inifcns_trans.cpp
index 75b812102bbccef71eb218b24a3e723c2f2e0cea..3f161d218c068e2a4d016fce5d5cfcb2d32f789e 100644 (file)
@@ -4,7 +4,7 @@
  *  functions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2010 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 <stdexcept>
-
 #include "inifcns.h"
 #include "ex.h"
 #include "constant.h"
@@ -35,6 +32,9 @@
 #include "pseries.h"
 #include "utils.h"
 
+#include <stdexcept>
+#include <vector>
+
 namespace GiNaC {
 
 //////////
@@ -55,24 +55,26 @@ static ex exp_eval(const ex & x)
        if (x.is_zero()) {
                return _ex1;
        }
+
        // exp(n*Pi*I/2) -> {+1|+I|-1|-I}
        const ex TwoExOverPiI=(_ex2*x)/(Pi*I);
        if (TwoExOverPiI.info(info_flags::integer)) {
-               const numeric z = mod(ex_to<numeric>(TwoExOverPiI),_num4);
-               if (z.is_equal(_num0))
+               const numeric z = mod(ex_to<numeric>(TwoExOverPiI),*_num4_p);
+               if (z.is_equal(*_num0_p))
                        return _ex1;
-               if (z.is_equal(_num1))
+               if (z.is_equal(*_num1_p))
                        return ex(I);
-               if (z.is_equal(_num2))
+               if (z.is_equal(*_num2_p))
                        return _ex_1;
-               if (z.is_equal(_num3))
+               if (z.is_equal(*_num3_p))
                        return ex(-I);
        }
+
        // exp(log(x)) -> x
        if (is_ex_the_function(x, log))
                return x.op(0);
        
-       // exp(float)
+       // exp(float) -> float
        if (x.info(info_flags::numeric) && !x.info(info_flags::crational))
                return exp(ex_to<numeric>(x));
        
@@ -87,9 +89,21 @@ static ex exp_deriv(const ex & x, unsigned deriv_param)
        return exp(x);
 }
 
+static ex exp_real_part(const ex & x)
+{
+       return exp(GiNaC::real_part(x))*cos(GiNaC::imag_part(x));
+}
+
+static ex exp_imag_part(const ex & x)
+{
+       return exp(GiNaC::real_part(x))*sin(GiNaC::imag_part(x));
+}
+
 REGISTER_FUNCTION(exp, eval_func(exp_eval).
                        evalf_func(exp_evalf).
                        derivative_func(exp_deriv).
+                       real_part_func(exp_real_part).
+                       imag_part_func(exp_imag_part).
                        latex_name("\\exp"));
 
 //////////
@@ -109,29 +123,25 @@ static ex log_eval(const ex & x)
        if (x.info(info_flags::numeric)) {
                if (x.is_zero())         // log(0) -> infinity
                        throw(pole_error("log_eval(): log(0)",0));
-               if (x.info(info_flags::real) && x.info(info_flags::negative))
+               if (x.info(info_flags::rational) && x.info(info_flags::negative))
                        return (log(-x)+I*Pi);
                if (x.is_equal(_ex1))  // log(1) -> 0
                        return _ex0;
                if (x.is_equal(I))       // log(I) -> Pi*I/2
-                       return (Pi*I*_num1_2);
+                       return (Pi*I*_ex1_2);
                if (x.is_equal(-I))      // log(-I) -> -Pi*I/2
-                       return (Pi*I*_num_1_2);
-               // log(float)
+                       return (Pi*I*_ex_1_2);
+
+               // log(float) -> float
                if (!x.info(info_flags::crational))
                        return log(ex_to<numeric>(x));
        }
+
        // log(exp(t)) -> t (if -Pi < t.imag() <= Pi):
        if (is_ex_the_function(x, exp)) {
                const ex &t = x.op(0);
-               if (is_a<symbol>(t) && (ex_to<symbol>(t).get_domain() == symbol_options::real)) {
+               if (t.info(info_flags::real))
                        return t;
-               }
-               if (t.info(info_flags::numeric)) {
-                       const numeric &nt = ex_to<numeric>(t);
-                       if (nt.is_real())
-                               return t;
-               }
        }
        
        return log(x).hold();
@@ -196,6 +206,22 @@ static ex log_series(const ex &arg,
                if (!argser.is_terminating() || argser.nops()!=1) {
                        // in this case n more (or less) terms are needed
                        // (sadly, to generate them, we have to start from the beginning)
+                       if (n == 0 && coeff == 1) {
+                               epvector epv;
+                               ex acc = (new pseries(rel, epv))->setflag(status_flags::dynallocated);
+                               epv.reserve(2);
+                               epv.push_back(expair(-1, _ex0));
+                               epv.push_back(expair(Order(_ex1), order));
+                               ex rest = pseries(rel, epv).add_series(argser);
+                               for (int i = order-1; i>0; --i) {
+                                       epvector cterm;
+                                       cterm.reserve(1);
+                                       cterm.push_back(expair(i%2 ? _ex1/i : _ex_1/i, _ex0));
+                                       acc = pseries(rel, cterm).add_series(ex_to<pseries>(acc));
+                                       acc = (ex_to<pseries>(rest)).mul_series(ex_to<pseries>(acc));
+                               }
+                               return acc;
+                       }
                        const ex newarg = ex_to<pseries>((arg/coeff).series(rel, order+n, options)).shift_exponents(-n).convert_to_poly(true);
                        return pseries(rel, seq).add_series(ex_to<pseries>(log(newarg).series(rel, order, options)));
                } else  // it was a monomial
@@ -218,10 +244,26 @@ static ex log_series(const ex &arg,
        throw do_taylor();  // caught by function::series()
 }
 
+static ex log_real_part(const ex & x)
+{
+       if (x.info(info_flags::nonnegative))
+               return log(x).hold();
+       return log(abs(x));
+}
+
+static ex log_imag_part(const ex & x)
+{
+       if (x.info(info_flags::nonnegative))
+               return 0;
+       return atan2(GiNaC::imag_part(x), GiNaC::real_part(x));
+}
+
 REGISTER_FUNCTION(log, eval_func(log_eval).
                        evalf_func(log_evalf).
                        derivative_func(log_deriv).
                        series_func(log_series).
+                       real_part_func(log_real_part).
+                       imag_part_func(log_imag_part).
                        latex_name("\\ln"));
 
 //////////
@@ -242,44 +284,47 @@ static ex sin_eval(const ex & x)
        const ex SixtyExOverPi = _ex60*x/Pi;
        ex sign = _ex1;
        if (SixtyExOverPi.info(info_flags::integer)) {
-               numeric z = mod(ex_to<numeric>(SixtyExOverPi),_num120);
-               if (z>=_num60) {
+               numeric z = mod(ex_to<numeric>(SixtyExOverPi),*_num120_p);
+               if (z>=*_num60_p) {
                        // wrap to interval [0, Pi)
-                       z -= _num60;
+                       z -= *_num60_p;
                        sign = _ex_1;
                }
-               if (z>_num30) {
+               if (z>*_num30_p) {
                        // wrap to interval [0, Pi/2)
-                       z = _num60-z;
+                       z = *_num60_p-z;
                }
-               if (z.is_equal(_num0))  // sin(0)       -> 0
+               if (z.is_equal(*_num0_p))  // sin(0)       -> 0
                        return _ex0;
-               if (z.is_equal(_num5))  // sin(Pi/12)   -> sqrt(6)/4*(1-sqrt(3)/3)
+               if (z.is_equal(*_num5_p))  // sin(Pi/12)   -> sqrt(6)/4*(1-sqrt(3)/3)
                        return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex_1_3*sqrt(_ex3));
-               if (z.is_equal(_num6))  // sin(Pi/10)   -> sqrt(5)/4-1/4
+               if (z.is_equal(*_num6_p))  // sin(Pi/10)   -> sqrt(5)/4-1/4
                        return sign*(_ex1_4*sqrt(_ex5)+_ex_1_4);
-               if (z.is_equal(_num10)) // sin(Pi/6)    -> 1/2
+               if (z.is_equal(*_num10_p)) // sin(Pi/6)    -> 1/2
                        return sign*_ex1_2;
-               if (z.is_equal(_num15)) // sin(Pi/4)    -> sqrt(2)/2
+               if (z.is_equal(*_num15_p)) // sin(Pi/4)    -> sqrt(2)/2
                        return sign*_ex1_2*sqrt(_ex2);
-               if (z.is_equal(_num18)) // sin(3/10*Pi) -> sqrt(5)/4+1/4
+               if (z.is_equal(*_num18_p)) // sin(3/10*Pi) -> sqrt(5)/4+1/4
                        return sign*(_ex1_4*sqrt(_ex5)+_ex1_4);
-               if (z.is_equal(_num20)) // sin(Pi/3)    -> sqrt(3)/2
+               if (z.is_equal(*_num20_p)) // sin(Pi/3)    -> sqrt(3)/2
                        return sign*_ex1_2*sqrt(_ex3);
-               if (z.is_equal(_num25)) // sin(5/12*Pi) -> sqrt(6)/4*(1+sqrt(3)/3)
+               if (z.is_equal(*_num25_p)) // sin(5/12*Pi) -> sqrt(6)/4*(1+sqrt(3)/3)
                        return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex1_3*sqrt(_ex3));
-               if (z.is_equal(_num30)) // sin(Pi/2)    -> 1
+               if (z.is_equal(*_num30_p)) // sin(Pi/2)    -> 1
                        return sign;
        }
-       
+
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // sin(asin(x)) -> x
                if (is_ex_the_function(x, asin))
                        return t;
+
                // sin(acos(x)) -> sqrt(1-x^2)
                if (is_ex_the_function(x, acos))
                        return sqrt(_ex1-power(t,_ex2));
+
                // sin(atan(x)) -> x/sqrt(1+x^2)
                if (is_ex_the_function(x, atan))
                        return t*power(_ex1+power(t,_ex2),_ex_1_2);
@@ -288,6 +333,10 @@ static ex sin_eval(const ex & x)
        // sin(float) -> float
        if (x.info(info_flags::numeric) && !x.info(info_flags::crational))
                return sin(ex_to<numeric>(x));
+
+       // sin() is odd
+       if (x.info(info_flags::negative))
+               return -sin(-x);
        
        return sin(x).hold();
 }
@@ -300,9 +349,21 @@ static ex sin_deriv(const ex & x, unsigned deriv_param)
        return cos(x);
 }
 
+static ex sin_real_part(const ex & x)
+{
+       return cosh(GiNaC::imag_part(x))*sin(GiNaC::real_part(x));
+}
+
+static ex sin_imag_part(const ex & x)
+{
+       return sinh(GiNaC::imag_part(x))*cos(GiNaC::real_part(x));
+}
+
 REGISTER_FUNCTION(sin, eval_func(sin_eval).
                        evalf_func(sin_evalf).
                        derivative_func(sin_deriv).
+                       real_part_func(sin_real_part).
+                       imag_part_func(sin_imag_part).
                        latex_name("\\sin"));
 
 //////////
@@ -323,44 +384,47 @@ static ex cos_eval(const ex & x)
        const ex SixtyExOverPi = _ex60*x/Pi;
        ex sign = _ex1;
        if (SixtyExOverPi.info(info_flags::integer)) {
-               numeric z = mod(ex_to<numeric>(SixtyExOverPi),_num120);
-               if (z>=_num60) {
+               numeric z = mod(ex_to<numeric>(SixtyExOverPi),*_num120_p);
+               if (z>=*_num60_p) {
                        // wrap to interval [0, Pi)
-                       z = _num120-z;
+                       z = *_num120_p-z;
                }
-               if (z>=_num30) {
+               if (z>=*_num30_p) {
                        // wrap to interval [0, Pi/2)
-                       z = _num60-z;
+                       z = *_num60_p-z;
                        sign = _ex_1;
                }
-               if (z.is_equal(_num0))  // cos(0)       -> 1
+               if (z.is_equal(*_num0_p))  // cos(0)       -> 1
                        return sign;
-               if (z.is_equal(_num5))  // cos(Pi/12)   -> sqrt(6)/4*(1+sqrt(3)/3)
+               if (z.is_equal(*_num5_p))  // cos(Pi/12)   -> sqrt(6)/4*(1+sqrt(3)/3)
                        return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex1_3*sqrt(_ex3));
-               if (z.is_equal(_num10)) // cos(Pi/6)    -> sqrt(3)/2
+               if (z.is_equal(*_num10_p)) // cos(Pi/6)    -> sqrt(3)/2
                        return sign*_ex1_2*sqrt(_ex3);
-               if (z.is_equal(_num12)) // cos(Pi/5)    -> sqrt(5)/4+1/4
+               if (z.is_equal(*_num12_p)) // cos(Pi/5)    -> sqrt(5)/4+1/4
                        return sign*(_ex1_4*sqrt(_ex5)+_ex1_4);
-               if (z.is_equal(_num15)) // cos(Pi/4)    -> sqrt(2)/2
+               if (z.is_equal(*_num15_p)) // cos(Pi/4)    -> sqrt(2)/2
                        return sign*_ex1_2*sqrt(_ex2);
-               if (z.is_equal(_num20)) // cos(Pi/3)    -> 1/2
+               if (z.is_equal(*_num20_p)) // cos(Pi/3)    -> 1/2
                        return sign*_ex1_2;
-               if (z.is_equal(_num24)) // cos(2/5*Pi)  -> sqrt(5)/4-1/4x
+               if (z.is_equal(*_num24_p)) // cos(2/5*Pi)  -> sqrt(5)/4-1/4x
                        return sign*(_ex1_4*sqrt(_ex5)+_ex_1_4);
-               if (z.is_equal(_num25)) // cos(5/12*Pi) -> sqrt(6)/4*(1-sqrt(3)/3)
+               if (z.is_equal(*_num25_p)) // cos(5/12*Pi) -> sqrt(6)/4*(1-sqrt(3)/3)
                        return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex_1_3*sqrt(_ex3));
-               if (z.is_equal(_num30)) // cos(Pi/2)    -> 0
+               if (z.is_equal(*_num30_p)) // cos(Pi/2)    -> 0
                        return _ex0;
        }
-       
+
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // cos(acos(x)) -> x
                if (is_ex_the_function(x, acos))
                        return t;
+
                // cos(asin(x)) -> sqrt(1-x^2)
                if (is_ex_the_function(x, asin))
                        return sqrt(_ex1-power(t,_ex2));
+
                // cos(atan(x)) -> 1/sqrt(1+x^2)
                if (is_ex_the_function(x, atan))
                        return power(_ex1+power(t,_ex2),_ex_1_2);
@@ -370,6 +434,10 @@ static ex cos_eval(const ex & x)
        if (x.info(info_flags::numeric) && !x.info(info_flags::crational))
                return cos(ex_to<numeric>(x));
        
+       // cos() is even
+       if (x.info(info_flags::negative))
+               return cos(-x);
+       
        return cos(x).hold();
 }
 
@@ -381,9 +449,21 @@ static ex cos_deriv(const ex & x, unsigned deriv_param)
        return -sin(x);
 }
 
+static ex cos_real_part(const ex & x)
+{
+       return cosh(GiNaC::imag_part(x))*cos(GiNaC::real_part(x));
+}
+
+static ex cos_imag_part(const ex & x)
+{
+       return -sinh(GiNaC::imag_part(x))*sin(GiNaC::real_part(x));
+}
+
 REGISTER_FUNCTION(cos, eval_func(cos_eval).
                        evalf_func(cos_evalf).
                        derivative_func(cos_deriv).
+                       real_part_func(cos_real_part).
+                       imag_part_func(cos_imag_part).
                        latex_name("\\cos"));
 
 //////////
@@ -404,40 +484,43 @@ static ex tan_eval(const ex & x)
        const ex SixtyExOverPi = _ex60*x/Pi;
        ex sign = _ex1;
        if (SixtyExOverPi.info(info_flags::integer)) {
-               numeric z = mod(ex_to<numeric>(SixtyExOverPi),_num60);
-               if (z>=_num60) {
+               numeric z = mod(ex_to<numeric>(SixtyExOverPi),*_num60_p);
+               if (z>=*_num60_p) {
                        // wrap to interval [0, Pi)
-                       z -= _num60;
+                       z -= *_num60_p;
                }
-               if (z>=_num30) {
+               if (z>=*_num30_p) {
                        // wrap to interval [0, Pi/2)
-                       z = _num60-z;
+                       z = *_num60_p-z;
                        sign = _ex_1;
                }
-               if (z.is_equal(_num0))  // tan(0)       -> 0
+               if (z.is_equal(*_num0_p))  // tan(0)       -> 0
                        return _ex0;
-               if (z.is_equal(_num5))  // tan(Pi/12)   -> 2-sqrt(3)
+               if (z.is_equal(*_num5_p))  // tan(Pi/12)   -> 2-sqrt(3)
                        return sign*(_ex2-sqrt(_ex3));
-               if (z.is_equal(_num10)) // tan(Pi/6)    -> sqrt(3)/3
+               if (z.is_equal(*_num10_p)) // tan(Pi/6)    -> sqrt(3)/3
                        return sign*_ex1_3*sqrt(_ex3);
-               if (z.is_equal(_num15)) // tan(Pi/4)    -> 1
+               if (z.is_equal(*_num15_p)) // tan(Pi/4)    -> 1
                        return sign;
-               if (z.is_equal(_num20)) // tan(Pi/3)    -> sqrt(3)
+               if (z.is_equal(*_num20_p)) // tan(Pi/3)    -> sqrt(3)
                        return sign*sqrt(_ex3);
-               if (z.is_equal(_num25)) // tan(5/12*Pi) -> 2+sqrt(3)
+               if (z.is_equal(*_num25_p)) // tan(5/12*Pi) -> 2+sqrt(3)
                        return sign*(sqrt(_ex3)+_ex2);
-               if (z.is_equal(_num30)) // tan(Pi/2)    -> infinity
+               if (z.is_equal(*_num30_p)) // tan(Pi/2)    -> infinity
                        throw (pole_error("tan_eval(): simple pole",1));
        }
-       
+
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // tan(atan(x)) -> x
                if (is_ex_the_function(x, atan))
                        return t;
+
                // tan(asin(x)) -> x/sqrt(1+x^2)
                if (is_ex_the_function(x, asin))
                        return t*power(_ex1-power(t,_ex2),_ex_1_2);
+
                // tan(acos(x)) -> sqrt(1-x^2)/x
                if (is_ex_the_function(x, acos))
                        return power(t,_ex_1)*sqrt(_ex1-power(t,_ex2));
@@ -448,6 +531,10 @@ static ex tan_eval(const ex & x)
                return tan(ex_to<numeric>(x));
        }
        
+       // tan() is odd
+       if (x.info(info_flags::negative))
+               return -tan(-x);
+       
        return tan(x).hold();
 }
 
@@ -459,6 +546,20 @@ static ex tan_deriv(const ex & x, unsigned deriv_param)
        return (_ex1+power(tan(x),_ex2));
 }
 
+static ex tan_real_part(const ex & x)
+{
+       ex a = GiNaC::real_part(x);
+       ex b = GiNaC::imag_part(x);
+       return tan(a)/(1+power(tan(a),2)*power(tan(b),2));
+}
+
+static ex tan_imag_part(const ex & x)
+{
+       ex a = GiNaC::real_part(x);
+       ex b = GiNaC::imag_part(x);
+       return tanh(b)/(1+power(tan(a),2)*power(tan(b),2));
+}
+
 static ex tan_series(const ex &x,
                      const relational &rel,
                      int order,
@@ -472,13 +573,15 @@ static ex tan_series(const ex &x,
        if (!(2*x_pt/Pi).info(info_flags::odd))
                throw do_taylor();  // caught by function::series()
        // if we got here we have to care for a simple pole
-       return (sin(x)/cos(x)).series(rel, order+2, options);
+       return (sin(x)/cos(x)).series(rel, order, options);
 }
 
 REGISTER_FUNCTION(tan, eval_func(tan_eval).
                        evalf_func(tan_evalf).
                        derivative_func(tan_deriv).
                        series_func(tan_series).
+                       real_part_func(tan_real_part).
+                       imag_part_func(tan_imag_part).
                        latex_name("\\tan"));
 
 //////////
@@ -496,24 +599,34 @@ static ex asin_evalf(const ex & x)
 static ex asin_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // asin(0) -> 0
                if (x.is_zero())
                        return x;
+
                // asin(1/2) -> Pi/6
                if (x.is_equal(_ex1_2))
                        return numeric(1,6)*Pi;
+
                // asin(1) -> Pi/2
                if (x.is_equal(_ex1))
-                       return _num1_2*Pi;
+                       return _ex1_2*Pi;
+
                // asin(-1/2) -> -Pi/6
                if (x.is_equal(_ex_1_2))
                        return numeric(-1,6)*Pi;
+
                // asin(-1) -> -Pi/2
                if (x.is_equal(_ex_1))
-                       return _num_1_2*Pi;
+                       return _ex_1_2*Pi;
+
                // asin(float) -> float
                if (!x.info(info_flags::crational))
                        return asin(ex_to<numeric>(x));
+
+               // asin() is odd
+               if (x.info(info_flags::negative))
+                       return -asin(-x);
        }
        
        return asin(x).hold();
@@ -547,24 +660,34 @@ static ex acos_evalf(const ex & x)
 static ex acos_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // acos(1) -> 0
                if (x.is_equal(_ex1))
                        return _ex0;
+
                // acos(1/2) -> Pi/3
                if (x.is_equal(_ex1_2))
                        return _ex1_3*Pi;
+
                // acos(0) -> Pi/2
                if (x.is_zero())
                        return _ex1_2*Pi;
+
                // acos(-1/2) -> 2/3*Pi
                if (x.is_equal(_ex_1_2))
                        return numeric(2,3)*Pi;
+
                // acos(-1) -> Pi
                if (x.is_equal(_ex_1))
                        return Pi;
+
                // acos(float) -> float
                if (!x.info(info_flags::crational))
                        return acos(ex_to<numeric>(x));
+
+               // acos(-x) -> Pi-acos(x)
+               if (x.info(info_flags::negative))
+                       return Pi-acos(-x);
        }
        
        return acos(x).hold();
@@ -598,20 +721,29 @@ static ex atan_evalf(const ex & x)
 static ex atan_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // atan(0) -> 0
                if (x.is_zero())
                        return _ex0;
+
                // atan(1) -> Pi/4
                if (x.is_equal(_ex1))
                        return _ex1_4*Pi;
+
                // atan(-1) -> -Pi/4
                if (x.is_equal(_ex_1))
                        return _ex_1_4*Pi;
+
                if (x.is_equal(I) || x.is_equal(-I))
                        throw (pole_error("atan_eval(): logarithmic pole",0));
+
                // atan(float) -> float
                if (!x.info(info_flags::crational))
                        return atan(ex_to<numeric>(x));
+
+               // atan() is odd
+               if (x.info(info_flags::negative))
+                       return -atan(-x);
        }
        
        return atan(x).hold();
@@ -681,19 +813,77 @@ REGISTER_FUNCTION(atan, eval_func(atan_eval).
 static ex atan2_evalf(const ex &y, const ex &x)
 {
        if (is_exactly_a<numeric>(y) && is_exactly_a<numeric>(x))
-               return atan2(ex_to<numeric>(y), ex_to<numeric>(x));
+               return atan(ex_to<numeric>(y), ex_to<numeric>(x));
        
        return atan2(y, x).hold();
 }
 
 static ex atan2_eval(const ex & y, const ex & x)
 {
-       if (y.info(info_flags::numeric) && !y.info(info_flags::crational) &&
-               x.info(info_flags::numeric) && !x.info(info_flags::crational)) {
-               return atan2_evalf(y,x);
+       if (y.is_zero()) {
+
+               // atan(0, 0) -> 0
+               if (x.is_zero())
+                       return _ex0;
+
+               // atan(0, x), x real and positive -> 0
+               if (x.info(info_flags::positive))
+                       return _ex0;
+
+               // atan(0, x), x real and negative -> Pi
+               if (x.info(info_flags::negative))
+                       return Pi;
        }
-       
-       return atan2(y,x).hold();
+
+       if (x.is_zero()) {
+
+               // atan(y, 0), y real and positive -> Pi/2
+               if (y.info(info_flags::positive))
+                       return _ex1_2*Pi;
+
+               // atan(y, 0), y real and negative -> -Pi/2
+               if (y.info(info_flags::real) && !y.is_zero())
+                       return _ex_1_2*Pi;
+       }
+
+       if (y.is_equal(x)) {
+
+               // atan(y, y), y real and positive -> Pi/4
+               if (y.info(info_flags::positive))
+                       return _ex1_4*Pi;
+
+               // atan(y, y), y real and negative -> -3/4*Pi
+               if (y.info(info_flags::negative))
+                       return numeric(-3, 4)*Pi;
+       }
+
+       if (y.is_equal(-x)) {
+
+               // atan(y, -y), y real and positive -> 3*Pi/4
+               if (y.info(info_flags::positive))
+                       return numeric(3, 4)*Pi;
+
+               // atan(y, -y), y real and negative -> -Pi/4
+               if (y.info(info_flags::negative))
+                       return _ex_1_4*Pi;
+       }
+
+       // atan(float, float) -> float
+       if (is_a<numeric>(y) && !y.info(info_flags::crational) &&
+           is_a<numeric>(x) && !x.info(info_flags::crational))
+               return atan(ex_to<numeric>(y), ex_to<numeric>(x));
+
+       // atan(real, real) -> atan(y/x) +/- Pi
+       if (y.info(info_flags::real) && x.info(info_flags::real)) {
+               if (x.info(info_flags::positive))
+                       return atan(y/x);
+               else if (y.info(info_flags::positive))
+                       return atan(y/x)+Pi;
+               else
+                       return atan(y/x)-Pi;
+       }
+
+       return atan2(y, x).hold();
 }    
 
 static ex atan2_deriv(const ex & y, const ex & x, unsigned deriv_param)
@@ -727,10 +917,18 @@ static ex sinh_evalf(const ex & x)
 static ex sinh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
-               if (x.is_zero())  // sinh(0) -> 0
+
+               // sinh(0) -> 0
+               if (x.is_zero())
                        return _ex0;        
-               if (!x.info(info_flags::crational))  // sinh(float) -> float
+
+               // sinh(float) -> float
+               if (!x.info(info_flags::crational))
                        return sinh(ex_to<numeric>(x));
+
+               // sinh() is odd
+               if (x.info(info_flags::negative))
+                       return -sinh(-x);
        }
        
        if ((x/Pi).info(info_flags::numeric) &&
@@ -739,12 +937,15 @@ static ex sinh_eval(const ex & x)
        
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // sinh(asinh(x)) -> x
                if (is_ex_the_function(x, asinh))
                        return t;
+
                // sinh(acosh(x)) -> sqrt(x-1) * sqrt(x+1)
                if (is_ex_the_function(x, acosh))
                        return sqrt(t-_ex1)*sqrt(t+_ex1);
+
                // sinh(atanh(x)) -> x/sqrt(1-x^2)
                if (is_ex_the_function(x, atanh))
                        return t*power(_ex1-power(t,_ex2),_ex_1_2);
@@ -761,9 +962,21 @@ static ex sinh_deriv(const ex & x, unsigned deriv_param)
        return cosh(x);
 }
 
+static ex sinh_real_part(const ex & x)
+{
+       return sinh(GiNaC::real_part(x))*cos(GiNaC::imag_part(x));
+}
+
+static ex sinh_imag_part(const ex & x)
+{
+       return cosh(GiNaC::real_part(x))*sin(GiNaC::imag_part(x));
+}
+
 REGISTER_FUNCTION(sinh, eval_func(sinh_eval).
                         evalf_func(sinh_evalf).
                         derivative_func(sinh_deriv).
+                        real_part_func(sinh_real_part).
+                        imag_part_func(sinh_imag_part).
                         latex_name("\\sinh"));
 
 //////////
@@ -781,10 +994,18 @@ static ex cosh_evalf(const ex & x)
 static ex cosh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
-               if (x.is_zero())  // cosh(0) -> 1
+
+               // cosh(0) -> 1
+               if (x.is_zero())
                        return _ex1;
-               if (!x.info(info_flags::crational))  // cosh(float) -> float
+
+               // cosh(float) -> float
+               if (!x.info(info_flags::crational))
                        return cosh(ex_to<numeric>(x));
+
+               // cosh() is even
+               if (x.info(info_flags::negative))
+                       return cosh(-x);
        }
        
        if ((x/Pi).info(info_flags::numeric) &&
@@ -793,12 +1014,15 @@ static ex cosh_eval(const ex & x)
        
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // cosh(acosh(x)) -> x
                if (is_ex_the_function(x, acosh))
                        return t;
+
                // cosh(asinh(x)) -> sqrt(1+x^2)
                if (is_ex_the_function(x, asinh))
                        return sqrt(_ex1+power(t,_ex2));
+
                // cosh(atanh(x)) -> 1/sqrt(1-x^2)
                if (is_ex_the_function(x, atanh))
                        return power(_ex1-power(t,_ex2),_ex_1_2);
@@ -815,9 +1039,21 @@ static ex cosh_deriv(const ex & x, unsigned deriv_param)
        return sinh(x);
 }
 
+static ex cosh_real_part(const ex & x)
+{
+       return cosh(GiNaC::real_part(x))*cos(GiNaC::imag_part(x));
+}
+
+static ex cosh_imag_part(const ex & x)
+{
+       return sinh(GiNaC::real_part(x))*sin(GiNaC::imag_part(x));
+}
+
 REGISTER_FUNCTION(cosh, eval_func(cosh_eval).
                         evalf_func(cosh_evalf).
                         derivative_func(cosh_deriv).
+                        real_part_func(cosh_real_part).
+                        imag_part_func(cosh_imag_part).
                         latex_name("\\cosh"));
 
 //////////
@@ -835,10 +1071,18 @@ static ex tanh_evalf(const ex & x)
 static ex tanh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
-               if (x.is_zero())  // tanh(0) -> 0
+
+               // tanh(0) -> 0
+               if (x.is_zero())
                        return _ex0;
-               if (!x.info(info_flags::crational))  // tanh(float) -> float
+
+               // tanh(float) -> float
+               if (!x.info(info_flags::crational))
                        return tanh(ex_to<numeric>(x));
+
+               // tanh() is odd
+               if (x.info(info_flags::negative))
+                       return -tanh(-x);
        }
        
        if ((x/Pi).info(info_flags::numeric) &&
@@ -847,12 +1091,15 @@ static ex tanh_eval(const ex & x)
        
        if (is_exactly_a<function>(x)) {
                const ex &t = x.op(0);
+
                // tanh(atanh(x)) -> x
                if (is_ex_the_function(x, atanh))
                        return t;
+
                // tanh(asinh(x)) -> x/sqrt(1+x^2)
                if (is_ex_the_function(x, asinh))
                        return t*power(_ex1+power(t,_ex2),_ex_1_2);
+
                // tanh(acosh(x)) -> sqrt(x-1)*sqrt(x+1)/x
                if (is_ex_the_function(x, acosh))
                        return sqrt(t-_ex1)*sqrt(t+_ex1)*power(t,_ex_1);
@@ -882,13 +1129,29 @@ static ex tanh_series(const ex &x,
        if (!(2*I*x_pt/Pi).info(info_flags::odd))
                throw do_taylor();  // caught by function::series()
        // if we got here we have to care for a simple pole
-       return (sinh(x)/cosh(x)).series(rel, order+2, options);
+       return (sinh(x)/cosh(x)).series(rel, order, options);
+}
+
+static ex tanh_real_part(const ex & x)
+{
+       ex a = GiNaC::real_part(x);
+       ex b = GiNaC::imag_part(x);
+       return tanh(a)/(1+power(tanh(a),2)*power(tan(b),2));
+}
+
+static ex tanh_imag_part(const ex & x)
+{
+       ex a = GiNaC::real_part(x);
+       ex b = GiNaC::imag_part(x);
+       return tan(b)/(1+power(tanh(a),2)*power(tan(b),2));
 }
 
 REGISTER_FUNCTION(tanh, eval_func(tanh_eval).
                         evalf_func(tanh_evalf).
                         derivative_func(tanh_deriv).
                         series_func(tanh_series).
+                        real_part_func(tanh_real_part).
+                        imag_part_func(tanh_imag_part).
                         latex_name("\\tanh"));
 
 //////////
@@ -906,12 +1169,18 @@ static ex asinh_evalf(const ex & x)
 static ex asinh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // asinh(0) -> 0
                if (x.is_zero())
                        return _ex0;
+
                // asinh(float) -> float
                if (!x.info(info_flags::crational))
                        return asinh(ex_to<numeric>(x));
+
+               // asinh() is odd
+               if (x.info(info_flags::negative))
+                       return -asinh(-x);
        }
        
        return asinh(x).hold();
@@ -944,18 +1213,26 @@ static ex acosh_evalf(const ex & x)
 static ex acosh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // acosh(0) -> Pi*I/2
                if (x.is_zero())
                        return Pi*I*numeric(1,2);
+
                // acosh(1) -> 0
                if (x.is_equal(_ex1))
                        return _ex0;
+
                // acosh(-1) -> Pi*I
                if (x.is_equal(_ex_1))
                        return Pi*I;
+
                // acosh(float) -> float
                if (!x.info(info_flags::crational))
                        return acosh(ex_to<numeric>(x));
+
+               // acosh(-x) -> Pi*I-acosh(x)
+               if (x.info(info_flags::negative))
+                       return Pi*I-acosh(-x);
        }
        
        return acosh(x).hold();
@@ -988,15 +1265,22 @@ static ex atanh_evalf(const ex & x)
 static ex atanh_eval(const ex & x)
 {
        if (x.info(info_flags::numeric)) {
+
                // atanh(0) -> 0
                if (x.is_zero())
                        return _ex0;
+
                // atanh({+|-}1) -> throw
                if (x.is_equal(_ex1) || x.is_equal(_ex_1))
                        throw (pole_error("atanh_eval(): logarithmic pole",0));
+
                // atanh(float) -> float
                if (!x.info(info_flags::crational))
                        return atanh(ex_to<numeric>(x));
+
+               // atanh() is odd
+               if (x.info(info_flags::negative))
+                       return -atanh(-x);
        }
        
        return atanh(x).hold();