Hi, this is a patch to add the base of the natural logarithm as a new constant EulerNum, and ensure that log(EulerNum) evaluates to 1. Of course, exp(1) will do fine for calculations. But for printing, it is nicer to see e^x instead of exp(1)^x or 2.718^x. Hope this is useful. Jan ---  ginac/constant.cpp      | 5 +++++  ginac/constant.h        | 1 +  ginac/inifcns_trans.cpp | 3 +++  ginac/numeric.cpp       | 5 +++++  ginac/numeric.h         | 1 +  ginsh/ginsh_lexer.lpp   | 1 +  6 files changed, 16 insertions(+) diff --git a/ginac/constant.cpp b/ginac/constant.cpp index a89711ef..60af44bc 100644 --- a/ginac/constant.cpp +++ b/ginac/constant.cpp @@ -91,6 +91,8 @@ void constant::read_archive(const archive_node &n, lst &sym_lst)              *this = Catalan;          else if (s == Euler.name)              *this = Euler; +        else if (s == EulerNum.name) +            *this = EulerNum;          else              throw (std::runtime_error("unknown constant '" + s + "' in archive"));      } else @@ -254,4 +256,7 @@ const constant Euler("Euler", EulerEvalf, "\\gamma_E", domain::positive);  /** Catalan's constant. (0.91597...)  Diverts straight into CLN for evalf(). */  const constant Catalan("Catalan", CatalanEvalf, "G", domain::positive); +/** Base of the natural logarithm */ +const constant EulerNum("EulerNum", EulerNumEvalf, "\\mathit{e}", domain::positive); +  } // namespace GiNaC diff --git a/ginac/constant.h b/ginac/constant.h index 92d07941..24839d46 100644 --- a/ginac/constant.h +++ b/ginac/constant.h @@ -82,6 +82,7 @@ GINAC_DECLARE_UNARCHIVER(constant);  extern const constant Pi;  extern const constant Catalan;  extern const constant Euler; +extern const constant EulerNum;  } // namespace GiNaC diff --git a/ginac/inifcns_trans.cpp b/ginac/inifcns_trans.cpp index 6f577bae..ef5f52f1 100644 --- a/ginac/inifcns_trans.cpp +++ b/ginac/inifcns_trans.cpp @@ -202,6 +202,9 @@ static ex log_eval(const ex & x)              return log(ex_to<numeric>(x));      } +    if (x.is_equal(EulerNum)) +            return *_num1_p; +      // log(exp(t)) -> t (if -Pi < t.imag() <= Pi):      if (is_ex_the_function(x, exp)) {          const ex &t = x.op(0); diff --git a/ginac/numeric.cpp b/ginac/numeric.cpp index 6da79977..addc012d 100644 --- a/ginac/numeric.cpp +++ b/ginac/numeric.cpp @@ -2515,6 +2515,11 @@ ex CatalanEvalf()      return numeric(cln::catalanconst(cln::default_float_format));  } +/** Floating point evaluation of base of natural logarithm. */ +ex EulerNumEvalf() +{ +    return exp(*_num1_p); // Suggestion by Vladimir Kisil on ginac-devel +}  /** _numeric_digits default ctor, checking for singleton invariance. */  _numeric_digits::_numeric_digits() diff --git a/ginac/numeric.h b/ginac/numeric.h index 0673d9a5..d25670f9 100644 --- a/ginac/numeric.h +++ b/ginac/numeric.h @@ -325,6 +325,7 @@ inline const numeric denom(const numeric &x)  ex PiEvalf();  ex EulerEvalf();  ex CatalanEvalf(); +ex EulerNumEvalf();  } // namespace GiNaC diff --git a/ginsh/ginsh_lexer.lpp b/ginsh/ginsh_lexer.lpp index 6e0732e7..bcfecd10 100644 --- a/ginsh/ginsh_lexer.lpp +++ b/ginsh/ginsh_lexer.lpp @@ -75,6 +75,7 @@ AN    [0-9a-zA-Z_]  Pi            yylval = Pi; return T_LITERAL;  Euler            yylval = Euler; return T_LITERAL;  Catalan            yylval = Catalan; return T_LITERAL; +EulerNum        yylval = EulerNum; return T_LITERAL;  FAIL            yylval = *new fail(); return T_LITERAL;  I            yylval = I; return T_NUMBER;  Digits            yylval = (long)Digits; return T_DIGITS; -- 2.43.0