Happy New Year!
[ginac.git] / ginac / inifcns.cpp
index 9cb5f67..e2a09b1 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's initially known functions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2015 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2019 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
@@ -109,7 +109,6 @@ static bool func_arg_info(const ex & arg, unsigned inf)
                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:
@@ -310,7 +309,7 @@ static ex abs_expand(const ex & arg, unsigned options)
                        else
                                prodseq.push_back(abs(*i));
                }
-               return (new mul(prodseq))->setflag(status_flags::dynallocated | status_flags::expanded);
+               return dynallocate<mul>(prodseq).setflag(status_flags::expanded);
        }
 
        if (options & expand_options::expand_function_args)
@@ -354,9 +353,9 @@ static ex abs_power(const ex & arg, const ex & exp)
 {
        if ((is_a<numeric>(exp) && ex_to<numeric>(exp).is_even()) || exp.info(info_flags::even)) {
                if (arg.info(info_flags::real) || arg.is_equal(arg.conjugate()))
-                       return power(arg, exp);
+                       return pow(arg, exp);
                else
-                       return power(arg, exp/2)*power(arg.conjugate(), exp/2);
+                       return pow(arg, exp/2) * pow(arg.conjugate(), exp/2);
        } else
                return power(abs(arg), exp).hold();
 }
@@ -1039,13 +1038,31 @@ REGISTER_FUNCTION(Order, eval_func(Order_eval).
 // Solve linear system
 //////////
 
+static void insert_symbols(exset &es, const ex &e)
+{
+       if (is_a<symbol>(e)) {
+               es.insert(e);
+       } else {
+               for (const ex &sube : e) {
+                       insert_symbols(es, sube);
+               }
+       }
+}
+
+static exset symbolset(const ex &e)
+{
+       exset s;
+       insert_symbols(s, e);
+       return s;
+}
+
 ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
 {
        // solve a system of linear equations
        if (eqns.info(info_flags::relation_equal)) {
                if (!symbols.info(info_flags::symbol))
                        throw(std::invalid_argument("lsolve(): 2nd argument must be a symbol"));
-               const ex sol = lsolve(lst(eqns),lst(symbols));
+               const ex sol = lsolve(lst{eqns}, lst{symbols});
                
                GINAC_ASSERT(sol.nops()==1);
                GINAC_ASSERT(is_exactly_a<relational>(sol.op(0)));
@@ -1054,20 +1071,20 @@ 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 or an equation"));
+       if (!(eqns.info(info_flags::list) || eqns.info(info_flags::exprseq))) {
+               throw(std::invalid_argument("lsolve(): 1st argument must be a list, a sequence, or an equation"));
        }
        for (size_t i=0; i<eqns.nops(); i++) {
                if (!eqns.op(i).info(info_flags::relation_equal)) {
                        throw(std::invalid_argument("lsolve(): 1st argument must be a list of equations"));
                }
        }
-       if (!symbols.info(info_flags::list)) {
-               throw(std::invalid_argument("lsolve(): 2nd argument must be a list or a symbol"));
+       if (!(symbols.info(info_flags::list) || symbols.info(info_flags::exprseq))) {
+               throw(std::invalid_argument("lsolve(): 2nd argument must be a list, a sequence, or a symbol"));
        }
        for (size_t i=0; i<symbols.nops(); i++) {
                if (!symbols.op(i).info(info_flags::symbol)) {
-                       throw(std::invalid_argument("lsolve(): 2nd argument must be a list of symbols"));
+                       throw(std::invalid_argument("lsolve(): 2nd argument must be a list or a sequence of symbols"));
                }
        }
        
@@ -1078,8 +1095,10 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
        
        for (size_t r=0; r<eqns.nops(); r++) {
                const ex eq = eqns.op(r).op(0)-eqns.op(r).op(1); // lhs-rhs==0
+               const exset syms = symbolset(eq);
                ex linpart = eq;
                for (size_t c=0; c<symbols.nops(); c++) {
+                       if (syms.count(symbols.op(c)) == 0) continue;
                        const ex co = eq.coeff(ex_to<symbol>(symbols.op(c)),1);
                        linpart -= co*symbols.op(c);
                        sys(r,c) = co;
@@ -1089,11 +1108,13 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
        }
        
        // test if system is linear and fill vars matrix
+       const exset sys_syms = symbolset(sys);
+       const exset rhs_syms = symbolset(rhs);
        for (size_t i=0; i<symbols.nops(); i++) {
                vars(i,0) = symbols.op(i);
-               if (sys.has(symbols.op(i)))
+               if (sys_syms.count(symbols.op(i)) != 0)
                        throw(std::logic_error("lsolve: system is not linear"));
-               if (rhs.has(symbols.op(i)))
+               if (rhs_syms.count(symbols.op(i)) != 0)
                        throw(std::logic_error("lsolve: system is not linear"));
        }
        
@@ -1103,12 +1124,12 @@ ex lsolve(const ex &eqns, const ex &symbols, unsigned options)
        } catch (const std::runtime_error & e) {
                // Probably singular matrix or otherwise overdetermined system:
                // It is consistent to return an empty list
-               return lst();
+               return lst{};
        }
        GINAC_ASSERT(solution.cols()==1);
        GINAC_ASSERT(solution.rows()==symbols.nops());
        
-       // return list of equations of the form lst(var1==sol1,var2==sol2,...)
+       // return list of equations of the form lst{var1==sol1,var2==sol2,...}
        lst sollist;
        for (size_t i=0; i<symbols.nops(); i++)
                sollist.append(symbols.op(i)==solution(i,0));