X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Finifcns_trans.cpp;h=872308b93f54e234a99ebf493a4416b4d6b7f1a8;hp=734c0ecb945fa1aecb0e19fbfb8d0527bc787610;hb=4405b29465293f3b6ab37745ff601f519b0256e2;hpb=7d10a252470cc6501b2c66bf9d6774c79b093761 diff --git a/ginac/inifcns_trans.cpp b/ginac/inifcns_trans.cpp index 734c0ecb..872308b9 100644 --- a/ginac/inifcns_trans.cpp +++ b/ginac/inifcns_trans.cpp @@ -4,7 +4,7 @@ * functions. */ /* - * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany + * GiNaC Copyright (C) 1999-2004 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 @@ -29,14 +29,13 @@ #include "constant.h" #include "numeric.h" #include "power.h" +#include "operators.h" #include "relational.h" #include "symbol.h" #include "pseries.h" #include "utils.h" -#ifndef NO_NAMESPACE_GINAC namespace GiNaC { -#endif // ndef NO_NAMESPACE_GINAC ////////// // exponential function @@ -44,39 +43,40 @@ namespace GiNaC { static ex exp_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(exp(x)) + if (is_exactly_a(x)) + return exp(ex_to(x)); - return exp(ex_to_numeric(x)); // -> numeric exp(numeric) + return exp(x).hold(); } static ex exp_eval(const ex & x) { // exp(0) -> 1 if (x.is_zero()) { - return _ex1(); + return _ex1; } + // exp(n*Pi*I/2) -> {+1|+I|-1|-I} - ex TwoExOverPiI=(_ex2()*x)/(Pi*I); + const ex TwoExOverPiI=(_ex2*x)/(Pi*I); if (TwoExOverPiI.info(info_flags::integer)) { - numeric z=mod(ex_to_numeric(TwoExOverPiI),_num4()); - if (z.is_equal(_num0())) - return _ex1(); - if (z.is_equal(_num1())) + const numeric z = mod(ex_to(TwoExOverPiI),_num4); + if (z.is_equal(_num0)) + return _ex1; + if (z.is_equal(_num1)) return ex(I); - if (z.is_equal(_num2())) - return _ex_1(); - if (z.is_equal(_num3())) + if (z.is_equal(_num2)) + return _ex_1; + if (z.is_equal(_num3)) 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_evalf(x); + return exp(ex_to(x)); return exp(x).hold(); } @@ -91,7 +91,8 @@ static ex exp_deriv(const ex & x, unsigned deriv_param) REGISTER_FUNCTION(exp, eval_func(exp_eval). evalf_func(exp_evalf). - derivative_func(exp_deriv)); + derivative_func(exp_deriv). + latex_name("\\exp")); ////////// // natural logarithm @@ -99,35 +100,39 @@ REGISTER_FUNCTION(exp, eval_func(exp_eval). static ex log_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(log(x)) + if (is_exactly_a(x)) + return log(ex_to(x)); - return log(ex_to_numeric(x)); // -> numeric log(numeric) + return log(x).hold(); } static ex log_eval(const ex & x) { if (x.info(info_flags::numeric)) { - if (x.is_equal(_ex0())) // log(0) -> infinity + 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)) return (log(-x)+I*Pi); - if (x.is_equal(_ex1())) // log(1) -> 0 - return _ex0(); + 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*_num1_2); if (x.is_equal(-I)) // log(-I) -> -Pi*I/2 - return (Pi*I*_num_1_2()); - // log(float) + return (Pi*I*_num_1_2); + + // log(float) -> float if (!x.info(info_flags::crational)) - return log_evalf(x); + return log(ex_to(x)); } + // log(exp(t)) -> t (if -Pi < t.imag() <= Pi): if (is_ex_the_function(x, exp)) { - ex t = x.op(0); + const ex &t = x.op(0); + if (is_a(t) && t.info(info_flags::real)) { + return t; + } if (t.info(info_flags::numeric)) { - numeric nt = ex_to_numeric(t); + const numeric &nt = ex_to(t); if (nt.is_real()) return t; } @@ -141,7 +146,7 @@ static ex log_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx log(x) -> 1/x - return power(x, _ex_1()); + return power(x, _ex_1); } static ex log_series(const ex &arg, @@ -149,16 +154,16 @@ static ex log_series(const ex &arg, int order, unsigned options) { - GINAC_ASSERT(is_ex_exactly_of_type(rel.lhs(),symbol)); + GINAC_ASSERT(is_a(rel.lhs())); ex arg_pt; bool must_expand_arg = false; // maybe substitution of rel into arg fails because of a pole try { - arg_pt = arg.subs(rel); + arg_pt = arg.subs(rel, subs_options::no_pattern); } catch (pole_error) { must_expand_arg = true; } - // or we are at the branch cut anyways + // or we are at the branch point anyways if (arg_pt.is_zero()) must_expand_arg = true; @@ -167,35 +172,67 @@ static ex log_series(const ex &arg, // This is the branch point: Series expand the argument first, then // trivially factorize it to isolate that part which has constant // leading coefficient in this fashion: - // x^n + Order(x^(n+m)) -> x^n * (1 + Order(x^m)). + // x^n + x^(n+1) +...+ Order(x^(n+m)) -> x^n * (1 + x +...+ Order(x^m)). // Return a plain n*log(x) for the x^n part and series expand the // other part. Add them together and reexpand again in order to have // one unnested pseries object. All this also works for negative n. - const pseries argser = ex_to_pseries(arg.series(rel, order, options)); - const symbol *s = static_cast(rel.lhs().bp); - const ex point = rel.rhs(); - const int n = argser.ldegree(*s); + pseries argser; // series expansion of log's argument + unsigned extra_ord = 0; // extra expansion order + do { + // oops, the argument expanded to a pure Order(x^something)... + argser = ex_to(arg.series(rel, order+extra_ord, options)); + ++extra_ord; + } while (!argser.is_terminating() && argser.nops()==1); + + const symbol &s = ex_to(rel.lhs()); + const ex &point = rel.rhs(); + const int n = argser.ldegree(s); epvector seq; - seq.push_back(expair(n*log(*s-point), _ex0())); + // construct what we carelessly called the n*log(x) term above + const ex coeff = argser.coeff(s, n); + // expand the log, but only if coeff is real and > 0, since otherwise + // it would make the branch cut run into the wrong direction + if (coeff.info(info_flags::positive)) + seq.push_back(expair(n*log(s-point)+log(coeff), _ex0)); + else + seq.push_back(expair(log(coeff*pow(s-point, n)), _ex0)); + if (!argser.is_terminating() || argser.nops()!=1) { - // in this case n more terms are needed - ex newarg = ex_to_pseries(arg.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))); + // in this case n more (or less) terms are needed + // (sadly, to generate them, we have to start from the beginning) + const ex newarg = ex_to((arg/coeff).series(rel, order+n, options)).shift_exponents(-n).convert_to_poly(true); + 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(acc)); + acc = (ex_to(rest)).mul_series(ex_to(acc)); + } + return acc; + } + return pseries(rel, seq).add_series(ex_to(log(newarg).series(rel, order, options))); } else // it was a monomial return pseries(rel, seq); } if (!(options & series_options::suppress_branchcut) && - arg_pt.info(info_flags::negative)) { + arg_pt.info(info_flags::negative)) { // method: // This is the branch cut: assemble the primitive series manually and // then add the corresponding complex step function. - const symbol *s = static_cast(rel.lhs().bp); - const ex point = rel.rhs(); + const symbol &s = ex_to(rel.lhs()); + const ex &point = rel.rhs(); const symbol foo; - ex replarg = series(log(arg), *s==foo, order, false).subs(foo==point); + const ex replarg = series(log(arg), s==foo, order).subs(foo==point, subs_options::no_pattern); epvector seq; - seq.push_back(expair(-I*csgn(arg*I)*Pi, _ex0())); - seq.push_back(expair(Order(_ex1()), order)); + seq.push_back(expair(-I*csgn(arg*I)*Pi, _ex0)); + seq.push_back(expair(Order(_ex1), order)); return series(replarg - I*Pi + pseries(rel, seq), rel, order); } throw do_taylor(); // caught by function::series() @@ -204,7 +241,8 @@ static ex log_series(const ex &arg, REGISTER_FUNCTION(log, eval_func(log_eval). evalf_func(log_evalf). derivative_func(log_deriv). - series_func(log_series)); + series_func(log_series). + latex_name("\\ln")); ////////// // sine (trigonometric function) @@ -212,65 +250,71 @@ REGISTER_FUNCTION(log, eval_func(log_eval). static ex sin_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(sin(x)) + if (is_exactly_a(x)) + return sin(ex_to(x)); - return sin(ex_to_numeric(x)); // -> numeric sin(numeric) + return sin(x).hold(); } static ex sin_eval(const ex & x) { // sin(n/d*Pi) -> { all known non-nested radicals } - ex SixtyExOverPi = _ex60()*x/Pi; - ex sign = _ex1(); + 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(SixtyExOverPi),_num120); + if (z>=_num60) { // wrap to interval [0, Pi) - z -= _num60(); - sign = _ex_1(); + z -= _num60; + sign = _ex_1; } - if (z>_num30()) { + if (z>_num30) { // wrap to interval [0, Pi/2) - z = _num60()-z; + z = _num60-z; } - if (z.is_equal(_num0())) // sin(0) -> 0 - return _ex0(); - if (z.is_equal(_num5())) // sin(Pi/12) -> sqrt(6)/4*(1-sqrt(3)/3) - return sign*_ex1_4()*power(_ex6(),_ex1_2())*(_ex1()+_ex_1_3()*power(_ex3(),_ex1_2())); - if (z.is_equal(_num6())) // sin(Pi/10) -> sqrt(5)/4-1/4 - return sign*(_ex1_4()*power(_ex5(),_ex1_2())+_ex_1_4()); - if (z.is_equal(_num10())) // sin(Pi/6) -> 1/2 - return sign*_ex1_2(); - if (z.is_equal(_num15())) // sin(Pi/4) -> sqrt(2)/2 - return sign*_ex1_2()*power(_ex2(),_ex1_2()); - if (z.is_equal(_num18())) // sin(3/10*Pi) -> sqrt(5)/4+1/4 - return sign*(_ex1_4()*power(_ex5(),_ex1_2())+_ex1_4()); - if (z.is_equal(_num20())) // sin(Pi/3) -> sqrt(3)/2 - return sign*_ex1_2()*power(_ex3(),_ex1_2()); - if (z.is_equal(_num25())) // sin(5/12*Pi) -> sqrt(6)/4*(1+sqrt(3)/3) - return sign*_ex1_4()*power(_ex6(),_ex1_2())*(_ex1()+_ex1_3()*power(_ex3(),_ex1_2())); - if (z.is_equal(_num30())) // sin(Pi/2) -> 1 - return sign*_ex1(); + if (z.is_equal(_num0)) // sin(0) -> 0 + return _ex0; + if (z.is_equal(_num5)) // 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 + return sign*(_ex1_4*sqrt(_ex5)+_ex_1_4); + if (z.is_equal(_num10)) // sin(Pi/6) -> 1/2 + return sign*_ex1_2; + if (z.is_equal(_num15)) // 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 + return sign*(_ex1_4*sqrt(_ex5)+_ex1_4); + if (z.is_equal(_num20)) // 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) + return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex1_3*sqrt(_ex3)); + if (z.is_equal(_num30)) // sin(Pi/2) -> 1 + return sign; } - - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + + if (is_exactly_a(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 power(_ex1()-power(t,_ex2()),_ex1_2()); - // sin(atan(x)) -> x*(1+x^2)^(-1/2) + 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()); + return t*power(_ex1+power(t,_ex2),_ex_1_2); } // sin(float) -> float if (x.info(info_flags::numeric) && !x.info(info_flags::crational)) - return sin_evalf(x); + return sin(ex_to(x)); + + // sin() is odd + if (x.info(info_flags::negative)) + return -sin(-x); return sin(x).hold(); } @@ -285,7 +329,8 @@ static ex sin_deriv(const ex & x, unsigned deriv_param) REGISTER_FUNCTION(sin, eval_func(sin_eval). evalf_func(sin_evalf). - derivative_func(sin_deriv)); + derivative_func(sin_deriv). + latex_name("\\sin")); ////////// // cosine (trigonometric function) @@ -293,65 +338,71 @@ REGISTER_FUNCTION(sin, eval_func(sin_eval). static ex cos_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(cos(x)) + if (is_exactly_a(x)) + return cos(ex_to(x)); - return cos(ex_to_numeric(x)); // -> numeric cos(numeric) + return cos(x).hold(); } static ex cos_eval(const ex & x) { // cos(n/d*Pi) -> { all known non-nested radicals } - ex SixtyExOverPi = _ex60()*x/Pi; - ex sign = _ex1(); + 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(SixtyExOverPi),_num120); + if (z>=_num60) { // wrap to interval [0, Pi) - z = _num120()-z; + z = _num120-z; } - if (z>=_num30()) { + if (z>=_num30) { // wrap to interval [0, Pi/2) - z = _num60()-z; - sign = _ex_1(); + z = _num60-z; + sign = _ex_1; } - if (z.is_equal(_num0())) // cos(0) -> 1 - return sign*_ex1(); - if (z.is_equal(_num5())) // cos(Pi/12) -> sqrt(6)/4*(1+sqrt(3)/3) - return sign*_ex1_4()*power(_ex6(),_ex1_2())*(_ex1()+_ex1_3()*power(_ex3(),_ex1_2())); - if (z.is_equal(_num10())) // cos(Pi/6) -> sqrt(3)/2 - return sign*_ex1_2()*power(_ex3(),_ex1_2()); - if (z.is_equal(_num12())) // cos(Pi/5) -> sqrt(5)/4+1/4 - return sign*(_ex1_4()*power(_ex5(),_ex1_2())+_ex1_4()); - if (z.is_equal(_num15())) // cos(Pi/4) -> sqrt(2)/2 - return sign*_ex1_2()*power(_ex2(),_ex1_2()); - if (z.is_equal(_num20())) // cos(Pi/3) -> 1/2 - return sign*_ex1_2(); - if (z.is_equal(_num24())) // cos(2/5*Pi) -> sqrt(5)/4-1/4x - return sign*(_ex1_4()*power(_ex5(),_ex1_2())+_ex_1_4()); - if (z.is_equal(_num25())) // cos(5/12*Pi) -> sqrt(6)/4*(1-sqrt(3)/3) - return sign*_ex1_4()*power(_ex6(),_ex1_2())*(_ex1()+_ex_1_3()*power(_ex3(),_ex1_2())); - if (z.is_equal(_num30())) // cos(Pi/2) -> 0 - return sign*_ex0(); + if (z.is_equal(_num0)) // cos(0) -> 1 + return sign; + if (z.is_equal(_num5)) // 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 + return sign*_ex1_2*sqrt(_ex3); + if (z.is_equal(_num12)) // 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 + return sign*_ex1_2*sqrt(_ex2); + if (z.is_equal(_num20)) // cos(Pi/3) -> 1/2 + return sign*_ex1_2; + if (z.is_equal(_num24)) // 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) + return sign*_ex1_4*sqrt(_ex6)*(_ex1+_ex_1_3*sqrt(_ex3)); + if (z.is_equal(_num30)) // cos(Pi/2) -> 0 + return _ex0; } - - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + + if (is_exactly_a(x)) { + const ex &t = x.op(0); + // cos(acos(x)) -> x if (is_ex_the_function(x, acos)) return t; - // cos(asin(x)) -> (1-x^2)^(1/2) + + // cos(asin(x)) -> sqrt(1-x^2) if (is_ex_the_function(x, asin)) - return power(_ex1()-power(t,_ex2()),_ex1_2()); - // cos(atan(x)) -> (1+x^2)^(-1/2) + 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()); + return power(_ex1+power(t,_ex2),_ex_1_2); } // cos(float) -> float if (x.info(info_flags::numeric) && !x.info(info_flags::crational)) - return cos_evalf(x); + return cos(ex_to(x)); + + // cos() is even + if (x.info(info_flags::negative)) + return cos(-x); return cos(x).hold(); } @@ -361,12 +412,13 @@ static ex cos_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx cos(x) -> -sin(x) - return _ex_1()*sin(x); + return -sin(x); } REGISTER_FUNCTION(cos, eval_func(cos_eval). evalf_func(cos_evalf). - derivative_func(cos_deriv)); + derivative_func(cos_deriv). + latex_name("\\cos")); ////////// // tangent (trigonometric function) @@ -374,63 +426,69 @@ REGISTER_FUNCTION(cos, eval_func(cos_eval). static ex tan_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(tan(x)) // -> numeric tan(numeric) + if (is_exactly_a(x)) + return tan(ex_to(x)); - return tan(ex_to_numeric(x)); + return tan(x).hold(); } static ex tan_eval(const ex & x) { // tan(n/d*Pi) -> { all known non-nested radicals } - ex SixtyExOverPi = _ex60()*x/Pi; - ex sign = _ex1(); + 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(SixtyExOverPi),_num60); + if (z>=_num60) { // wrap to interval [0, Pi) - z -= _num60(); + z -= _num60; } - if (z>=_num30()) { + if (z>=_num30) { // wrap to interval [0, Pi/2) - z = _num60()-z; - sign = _ex_1(); + z = _num60-z; + sign = _ex_1; } - if (z.is_equal(_num0())) // tan(0) -> 0 - return _ex0(); - if (z.is_equal(_num5())) // tan(Pi/12) -> 2-sqrt(3) - return sign*(_ex2()-power(_ex3(),_ex1_2())); - if (z.is_equal(_num10())) // tan(Pi/6) -> sqrt(3)/3 - return sign*_ex1_3()*power(_ex3(),_ex1_2()); - if (z.is_equal(_num15())) // tan(Pi/4) -> 1 - return sign*_ex1(); - if (z.is_equal(_num20())) // tan(Pi/3) -> sqrt(3) - return sign*power(_ex3(),_ex1_2()); - if (z.is_equal(_num25())) // tan(5/12*Pi) -> 2+sqrt(3) - return sign*(power(_ex3(),_ex1_2())+_ex2()); - if (z.is_equal(_num30())) // tan(Pi/2) -> infinity + if (z.is_equal(_num0)) // tan(0) -> 0 + return _ex0; + if (z.is_equal(_num5)) // tan(Pi/12) -> 2-sqrt(3) + return sign*(_ex2-sqrt(_ex3)); + if (z.is_equal(_num10)) // tan(Pi/6) -> sqrt(3)/3 + return sign*_ex1_3*sqrt(_ex3); + if (z.is_equal(_num15)) // tan(Pi/4) -> 1 + return sign; + if (z.is_equal(_num20)) // tan(Pi/3) -> sqrt(3) + return sign*sqrt(_ex3); + if (z.is_equal(_num25)) // tan(5/12*Pi) -> 2+sqrt(3) + return sign*(sqrt(_ex3)+_ex2); + if (z.is_equal(_num30)) // tan(Pi/2) -> infinity throw (pole_error("tan_eval(): simple pole",1)); } - - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + + if (is_exactly_a(x)) { + const ex &t = x.op(0); + // tan(atan(x)) -> x if (is_ex_the_function(x, atan)) return t; - // tan(asin(x)) -> x*(1+x^2)^(-1/2) + + // 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)) -> (1-x^2)^(1/2)/x + 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())*power(_ex1()-power(t,_ex2()),_ex1_2()); + return power(t,_ex_1)*sqrt(_ex1-power(t,_ex2)); } // tan(float) -> float if (x.info(info_flags::numeric) && !x.info(info_flags::crational)) { - return tan_evalf(x); + return tan(ex_to(x)); } + // tan() is odd + if (x.info(info_flags::negative)) + return -tan(-x); + return tan(x).hold(); } @@ -439,7 +497,7 @@ static ex tan_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx tan(x) -> 1+tan(x)^2; - return (_ex1()+power(tan(x),_ex2())); + return (_ex1+power(tan(x),_ex2)); } static ex tan_series(const ex &x, @@ -447,20 +505,22 @@ static ex tan_series(const ex &x, int order, unsigned options) { + GINAC_ASSERT(is_a(rel.lhs())); // method: // Taylor series where there is no pole falls back to tan_deriv. // On a pole simply expand sin(x)/cos(x). - const ex x_pt = x.subs(rel); + const ex x_pt = x.subs(rel, subs_options::no_pattern); 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); + 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)); + series_func(tan_series). + latex_name("\\tan")); ////////// // inverse sine (arc sine) @@ -468,34 +528,43 @@ REGISTER_FUNCTION(tan, eval_func(tan_eval). static ex asin_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(asin(x)) + if (is_exactly_a(x)) + return asin(ex_to(x)); - return asin(ex_to_numeric(x)); // -> numeric asin(numeric) + return asin(x).hold(); } 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())) + if (x.is_equal(_ex1_2)) return numeric(1,6)*Pi; + // asin(1) -> Pi/2 - if (x.is_equal(_ex1())) - return _num1_2()*Pi; + if (x.is_equal(_ex1)) + return _num1_2*Pi; + // asin(-1/2) -> -Pi/6 - if (x.is_equal(_ex_1_2())) + 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; + if (x.is_equal(_ex_1)) + return _num_1_2*Pi; + // asin(float) -> float if (!x.info(info_flags::crational)) - return asin_evalf(x); + return asin(ex_to(x)); + + // asin() is odd + if (x.info(info_flags::negative)) + return -asin(-x); } return asin(x).hold(); @@ -506,12 +575,13 @@ static ex asin_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx asin(x) -> 1/sqrt(1-x^2) - return power(1-power(x,_ex2()),_ex_1_2()); + return power(1-power(x,_ex2),_ex_1_2); } REGISTER_FUNCTION(asin, eval_func(asin_eval). evalf_func(asin_evalf). - derivative_func(asin_deriv)); + derivative_func(asin_deriv). + latex_name("\\arcsin")); ////////// // inverse cosine (arc cosine) @@ -519,34 +589,43 @@ REGISTER_FUNCTION(asin, eval_func(asin_eval). static ex acos_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(acos(x)) + if (is_exactly_a(x)) + return acos(ex_to(x)); - return acos(ex_to_numeric(x)); // -> numeric acos(numeric) + return acos(x).hold(); } static ex acos_eval(const ex & x) { if (x.info(info_flags::numeric)) { + // acos(1) -> 0 - if (x.is_equal(_ex1())) - return _ex0(); + if (x.is_equal(_ex1)) + return _ex0; + // acos(1/2) -> Pi/3 - if (x.is_equal(_ex1_2())) - return _ex1_3()*Pi; + if (x.is_equal(_ex1_2)) + return _ex1_3*Pi; + // acos(0) -> Pi/2 if (x.is_zero()) - return _ex1_2()*Pi; + return _ex1_2*Pi; + // acos(-1/2) -> 2/3*Pi - if (x.is_equal(_ex_1_2())) + if (x.is_equal(_ex_1_2)) return numeric(2,3)*Pi; + // acos(-1) -> Pi - if (x.is_equal(_ex_1())) + if (x.is_equal(_ex_1)) return Pi; + // acos(float) -> float if (!x.info(info_flags::crational)) - return acos_evalf(x); + return acos(ex_to(x)); + + // acos(-x) -> Pi-acos(x) + if (x.info(info_flags::negative)) + return Pi-acos(-x); } return acos(x).hold(); @@ -557,12 +636,13 @@ static ex acos_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx acos(x) -> -1/sqrt(1-x^2) - return _ex_1()*power(1-power(x,_ex2()),_ex_1_2()); + return -power(1-power(x,_ex2),_ex_1_2); } REGISTER_FUNCTION(acos, eval_func(acos_eval). evalf_func(acos_evalf). - derivative_func(acos_deriv)); + derivative_func(acos_deriv). + latex_name("\\arccos")); ////////// // inverse tangent (arc tangent) @@ -570,61 +650,180 @@ REGISTER_FUNCTION(acos, eval_func(acos_eval). static ex atan_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(atan(x)) + if (is_exactly_a(x)) + return atan(ex_to(x)); - return atan(ex_to_numeric(x)); // -> numeric atan(numeric) + return atan(x).hold(); } static ex atan_eval(const ex & x) { if (x.info(info_flags::numeric)) { + // atan(0) -> 0 - if (x.is_equal(_ex0())) - return _ex0(); + 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_evalf(x); + return atan(ex_to(x)); + + // atan() is odd + if (x.info(info_flags::negative)) + return -atan(-x); } return atan(x).hold(); -} +} static ex atan_deriv(const ex & x, unsigned deriv_param) { GINAC_ASSERT(deriv_param==0); // d/dx atan(x) -> 1/(1+x^2) - return power(_ex1()+power(x,_ex2()), _ex_1()); + return power(_ex1+power(x,_ex2), _ex_1); +} + +static ex atan_series(const ex &arg, + const relational &rel, + int order, + unsigned options) +{ + GINAC_ASSERT(is_a(rel.lhs())); + // method: + // Taylor series where there is no pole or cut falls back to atan_deriv. + // There are two branch cuts, one runnig from I up the imaginary axis and + // one running from -I down the imaginary axis. The points I and -I are + // poles. + // On the branch cuts and the poles series expand + // (log(1+I*x)-log(1-I*x))/(2*I) + // instead. + const ex arg_pt = arg.subs(rel, subs_options::no_pattern); + if (!(I*arg_pt).info(info_flags::real)) + throw do_taylor(); // Re(x) != 0 + if ((I*arg_pt).info(info_flags::real) && abs(I*arg_pt)<_ex1) + throw do_taylor(); // Re(x) == 0, but abs(x)<1 + // care for the poles, using the defining formula for atan()... + if (arg_pt.is_equal(I) || arg_pt.is_equal(-I)) + return ((log(1+I*arg)-log(1-I*arg))/(2*I)).series(rel, order, options); + if (!(options & series_options::suppress_branchcut)) { + // method: + // This is the branch cut: assemble the primitive series manually and + // then add the corresponding complex step function. + const symbol &s = ex_to(rel.lhs()); + const ex &point = rel.rhs(); + const symbol foo; + const ex replarg = series(atan(arg), s==foo, order).subs(foo==point, subs_options::no_pattern); + ex Order0correction = replarg.op(0)+csgn(arg)*Pi*_ex_1_2; + if ((I*arg_pt)<_ex0) + Order0correction += log((I*arg_pt+_ex_1)/(I*arg_pt+_ex1))*I*_ex_1_2; + else + Order0correction += log((I*arg_pt+_ex1)/(I*arg_pt+_ex_1))*I*_ex1_2; + epvector seq; + seq.push_back(expair(Order0correction, _ex0)); + seq.push_back(expair(Order(_ex1), order)); + return series(replarg - pseries(rel, seq), rel, order); + } + throw do_taylor(); } REGISTER_FUNCTION(atan, eval_func(atan_eval). evalf_func(atan_evalf). - derivative_func(atan_deriv)); + derivative_func(atan_deriv). + series_func(atan_series). + latex_name("\\arctan")); ////////// // inverse tangent (atan2(y,x)) ////////// -static ex atan2_evalf(const ex & y, const ex & x) +static ex atan2_evalf(const ex &y, const ex &x) { - BEGIN_TYPECHECK - TYPECHECK(y,numeric) - TYPECHECK(x,numeric) - END_TYPECHECK(atan2(y,x)) + if (is_exactly_a(y) && is_exactly_a(x)) + return atan(ex_to(y), ex_to(x)); - return atan(ex_to_numeric(y),ex_to_numeric(x)); // -> numeric atan(numeric) + 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.info(info_flags::numeric) && x.info(info_flags::numeric)) { + + 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 _ex_1*Pi; + } + + 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::negative)) + 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 (!y.info(info_flags::crational) && !x.info(info_flags::crational)) + return atan(ex_to(y), ex_to(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(); + + return atan2(y, x).hold(); } static ex atan2_deriv(const ex & y, const ex & x, unsigned deriv_param) @@ -633,10 +832,10 @@ static ex atan2_deriv(const ex & y, const ex & x, unsigned deriv_param) if (deriv_param==0) { // d/dy atan(y,x) - return x*power(power(x,_ex2())+power(y,_ex2()),_ex_1()); + return x*power(power(x,_ex2)+power(y,_ex2),_ex_1); } // d/dx atan(y,x) - return -y*power(power(x,_ex2())+power(y,_ex2()),_ex_1()); + return -y*power(power(x,_ex2)+power(y,_ex2),_ex_1); } REGISTER_FUNCTION(atan2, eval_func(atan2_eval). @@ -649,37 +848,47 @@ REGISTER_FUNCTION(atan2, eval_func(atan2_eval). static ex sinh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(sinh(x)) + if (is_exactly_a(x)) + return sinh(ex_to(x)); - return sinh(ex_to_numeric(x)); // -> numeric sinh(numeric) + return sinh(x).hold(); } static ex sinh_eval(const ex & x) { if (x.info(info_flags::numeric)) { - if (x.is_zero()) // sinh(0) -> 0 - return _ex0(); - if (!x.info(info_flags::crational)) // sinh(float) -> float - return sinh_evalf(x); + + // sinh(0) -> 0 + if (x.is_zero()) + return _ex0; + + // sinh(float) -> float + if (!x.info(info_flags::crational)) + return sinh(ex_to(x)); + + // sinh() is odd + if (x.info(info_flags::negative)) + return -sinh(-x); } if ((x/Pi).info(info_flags::numeric) && - ex_to_numeric(x/Pi).real().is_zero()) // sinh(I*x) -> I*sin(x) + ex_to(x/Pi).real().is_zero()) // sinh(I*x) -> I*sin(x) return I*sin(x/I); - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + if (is_exactly_a(x)) { + const ex &t = x.op(0); + // sinh(asinh(x)) -> x if (is_ex_the_function(x, asinh)) return t; - // sinh(acosh(x)) -> (x-1)^(1/2) * (x+1)^(1/2) + + // sinh(acosh(x)) -> sqrt(x-1) * sqrt(x+1) if (is_ex_the_function(x, acosh)) - return power(t-_ex1(),_ex1_2())*power(t+_ex1(),_ex1_2()); - // sinh(atanh(x)) -> x*(1-x^2)^(-1/2) + 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()); + return t*power(_ex1-power(t,_ex2),_ex_1_2); } return sinh(x).hold(); @@ -695,7 +904,8 @@ static ex sinh_deriv(const ex & x, unsigned deriv_param) REGISTER_FUNCTION(sinh, eval_func(sinh_eval). evalf_func(sinh_evalf). - derivative_func(sinh_deriv)); + derivative_func(sinh_deriv). + latex_name("\\sinh")); ////////// // hyperbolic cosine (trigonometric function) @@ -703,37 +913,47 @@ REGISTER_FUNCTION(sinh, eval_func(sinh_eval). static ex cosh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(cosh(x)) + if (is_exactly_a(x)) + return cosh(ex_to(x)); - return cosh(ex_to_numeric(x)); // -> numeric cosh(numeric) + return cosh(x).hold(); } static ex cosh_eval(const ex & x) { if (x.info(info_flags::numeric)) { - if (x.is_zero()) // cosh(0) -> 1 - return _ex1(); - if (!x.info(info_flags::crational)) // cosh(float) -> float - return cosh_evalf(x); + + // cosh(0) -> 1 + if (x.is_zero()) + return _ex1; + + // cosh(float) -> float + if (!x.info(info_flags::crational)) + return cosh(ex_to(x)); + + // cosh() is even + if (x.info(info_flags::negative)) + return cosh(-x); } if ((x/Pi).info(info_flags::numeric) && - ex_to_numeric(x/Pi).real().is_zero()) // cosh(I*x) -> cos(x) + ex_to(x/Pi).real().is_zero()) // cosh(I*x) -> cos(x) return cos(x/I); - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + if (is_exactly_a(x)) { + const ex &t = x.op(0); + // cosh(acosh(x)) -> x if (is_ex_the_function(x, acosh)) return t; - // cosh(asinh(x)) -> (1+x^2)^(1/2) + + // cosh(asinh(x)) -> sqrt(1+x^2) if (is_ex_the_function(x, asinh)) - return power(_ex1()+power(t,_ex2()),_ex1_2()); - // cosh(atanh(x)) -> (1-x^2)^(-1/2) + 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()); + return power(_ex1-power(t,_ex2),_ex_1_2); } return cosh(x).hold(); @@ -749,8 +969,8 @@ static ex cosh_deriv(const ex & x, unsigned deriv_param) REGISTER_FUNCTION(cosh, eval_func(cosh_eval). evalf_func(cosh_evalf). - derivative_func(cosh_deriv)); - + derivative_func(cosh_deriv). + latex_name("\\cosh")); ////////// // hyperbolic tangent (trigonometric function) @@ -758,37 +978,47 @@ REGISTER_FUNCTION(cosh, eval_func(cosh_eval). static ex tanh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(tanh(x)) + if (is_exactly_a(x)) + return tanh(ex_to(x)); - return tanh(ex_to_numeric(x)); // -> numeric tanh(numeric) + return tanh(x).hold(); } static ex tanh_eval(const ex & x) { if (x.info(info_flags::numeric)) { - if (x.is_zero()) // tanh(0) -> 0 - return _ex0(); - if (!x.info(info_flags::crational)) // tanh(float) -> float - return tanh_evalf(x); + + // tanh(0) -> 0 + if (x.is_zero()) + return _ex0; + + // tanh(float) -> float + if (!x.info(info_flags::crational)) + return tanh(ex_to(x)); + + // tanh() is odd + if (x.info(info_flags::negative)) + return -tanh(-x); } if ((x/Pi).info(info_flags::numeric) && - ex_to_numeric(x/Pi).real().is_zero()) // tanh(I*x) -> I*tan(x); + ex_to(x/Pi).real().is_zero()) // tanh(I*x) -> I*tan(x); return I*tan(x/I); - if (is_ex_exactly_of_type(x, function)) { - ex t = x.op(0); + if (is_exactly_a(x)) { + const ex &t = x.op(0); + // tanh(atanh(x)) -> x if (is_ex_the_function(x, atanh)) return t; - // tanh(asinh(x)) -> x*(1+x^2)^(-1/2) + + // 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)) -> (x-1)^(1/2)*(x+1)^(1/2)/x + 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 power(t-_ex1(),_ex1_2())*power(t+_ex1(),_ex1_2())*power(t,_ex_1()); + return sqrt(t-_ex1)*sqrt(t+_ex1)*power(t,_ex_1); } return tanh(x).hold(); @@ -799,7 +1029,7 @@ static ex tanh_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx tanh(x) -> 1-tanh(x)^2 - return _ex1()-power(tanh(x),_ex2()); + return _ex1-power(tanh(x),_ex2); } static ex tanh_series(const ex &x, @@ -807,20 +1037,22 @@ static ex tanh_series(const ex &x, int order, unsigned options) { + GINAC_ASSERT(is_a(rel.lhs())); // method: // Taylor series where there is no pole falls back to tanh_deriv. // On a pole simply expand sinh(x)/cosh(x). - const ex x_pt = x.subs(rel); + const ex x_pt = x.subs(rel, subs_options::no_pattern); 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); + return (sinh(x)/cosh(x)).series(rel, order, options); } REGISTER_FUNCTION(tanh, eval_func(tanh_eval). evalf_func(tanh_evalf). derivative_func(tanh_deriv). - series_func(tanh_series)); + series_func(tanh_series). + latex_name("\\tanh")); ////////// // inverse hyperbolic sine (trigonometric function) @@ -828,22 +1060,27 @@ REGISTER_FUNCTION(tanh, eval_func(tanh_eval). static ex asinh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(asinh(x)) + if (is_exactly_a(x)) + return asinh(ex_to(x)); - return asinh(ex_to_numeric(x)); // -> numeric asinh(numeric) + return asinh(x).hold(); } static ex asinh_eval(const ex & x) { if (x.info(info_flags::numeric)) { + // asinh(0) -> 0 if (x.is_zero()) - return _ex0(); + return _ex0; + // asinh(float) -> float if (!x.info(info_flags::crational)) - return asinh_evalf(x); + return asinh(ex_to(x)); + + // asinh() is odd + if (x.info(info_flags::negative)) + return -asinh(-x); } return asinh(x).hold(); @@ -854,7 +1091,7 @@ static ex asinh_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx asinh(x) -> 1/sqrt(1+x^2) - return power(_ex1()+power(x,_ex2()),_ex_1_2()); + return power(_ex1+power(x,_ex2),_ex_1_2); } REGISTER_FUNCTION(asinh, eval_func(asinh_eval). @@ -867,28 +1104,35 @@ REGISTER_FUNCTION(asinh, eval_func(asinh_eval). static ex acosh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(acosh(x)) + if (is_exactly_a(x)) + return acosh(ex_to(x)); - return acosh(ex_to_numeric(x)); // -> numeric acosh(numeric) + return acosh(x).hold(); } 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(); + if (x.is_equal(_ex1)) + return _ex0; + // acosh(-1) -> Pi*I - if (x.is_equal(_ex_1())) + if (x.is_equal(_ex_1)) return Pi*I; + // acosh(float) -> float if (!x.info(info_flags::crational)) - return acosh_evalf(x); + return acosh(ex_to(x)); + + // acosh(-x) -> Pi*I-acosh(x) + if (x.info(info_flags::negative)) + return Pi*I-acosh(-x); } return acosh(x).hold(); @@ -899,7 +1143,7 @@ static ex acosh_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx acosh(x) -> 1/(sqrt(x-1)*sqrt(x+1)) - return power(x+_ex_1(),_ex_1_2())*power(x+_ex1(),_ex_1_2()); + return power(x+_ex_1,_ex_1_2)*power(x+_ex1,_ex_1_2); } REGISTER_FUNCTION(acosh, eval_func(acosh_eval). @@ -912,25 +1156,31 @@ REGISTER_FUNCTION(acosh, eval_func(acosh_eval). static ex atanh_evalf(const ex & x) { - BEGIN_TYPECHECK - TYPECHECK(x,numeric) - END_TYPECHECK(atanh(x)) + if (is_exactly_a(x)) + return atanh(ex_to(x)); - return atanh(ex_to_numeric(x)); // -> numeric atanh(numeric) + return atanh(x).hold(); } static ex atanh_eval(const ex & x) { if (x.info(info_flags::numeric)) { + // atanh(0) -> 0 if (x.is_zero()) - return _ex0(); + return _ex0; + // atanh({+|-}1) -> throw - if (x.is_equal(_ex1()) || x.is_equal(_ex_1())) + 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_evalf(x); + return atanh(ex_to(x)); + + // atanh() is odd + if (x.info(info_flags::negative)) + return -atanh(-x); } return atanh(x).hold(); @@ -941,13 +1191,56 @@ static ex atanh_deriv(const ex & x, unsigned deriv_param) GINAC_ASSERT(deriv_param==0); // d/dx atanh(x) -> 1/(1-x^2) - return power(_ex1()-power(x,_ex2()),_ex_1()); + return power(_ex1-power(x,_ex2),_ex_1); +} + +static ex atanh_series(const ex &arg, + const relational &rel, + int order, + unsigned options) +{ + GINAC_ASSERT(is_a(rel.lhs())); + // method: + // Taylor series where there is no pole or cut falls back to atanh_deriv. + // There are two branch cuts, one runnig from 1 up the real axis and one + // one running from -1 down the real axis. The points 1 and -1 are poles + // On the branch cuts and the poles series expand + // (log(1+x)-log(1-x))/2 + // instead. + const ex arg_pt = arg.subs(rel, subs_options::no_pattern); + if (!(arg_pt).info(info_flags::real)) + throw do_taylor(); // Im(x) != 0 + if ((arg_pt).info(info_flags::real) && abs(arg_pt)<_ex1) + throw do_taylor(); // Im(x) == 0, but abs(x)<1 + // care for the poles, using the defining formula for atanh()... + if (arg_pt.is_equal(_ex1) || arg_pt.is_equal(_ex_1)) + return ((log(_ex1+arg)-log(_ex1-arg))*_ex1_2).series(rel, order, options); + // ...and the branch cuts (the discontinuity at the cut being just I*Pi) + if (!(options & series_options::suppress_branchcut)) { + // method: + // This is the branch cut: assemble the primitive series manually and + // then add the corresponding complex step function. + const symbol &s = ex_to(rel.lhs()); + const ex &point = rel.rhs(); + const symbol foo; + const ex replarg = series(atanh(arg), s==foo, order).subs(foo==point, subs_options::no_pattern); + ex Order0correction = replarg.op(0)+csgn(I*arg)*Pi*I*_ex1_2; + if (arg_pt<_ex0) + Order0correction += log((arg_pt+_ex_1)/(arg_pt+_ex1))*_ex1_2; + else + Order0correction += log((arg_pt+_ex1)/(arg_pt+_ex_1))*_ex_1_2; + epvector seq; + seq.push_back(expair(Order0correction, _ex0)); + seq.push_back(expair(Order(_ex1), order)); + return series(replarg - pseries(rel, seq), rel, order); + } + throw do_taylor(); } REGISTER_FUNCTION(atanh, eval_func(atanh_eval). evalf_func(atanh_evalf). - derivative_func(atanh_deriv)); + derivative_func(atanh_deriv). + series_func(atanh_series)); + -#ifndef NO_NAMESPACE_GINAC } // namespace GiNaC -#endif // ndef NO_NAMESPACE_GINAC