]> www.ginac.de Git - ginac.git/blobdiff - ginac/pseries.cpp
- increased compatibility with RedHat's readline-4.2-1 package
[ginac.git] / ginac / pseries.cpp
index 37f295894077d96ca7552b7f3c639ee48f2004ed..5812982447a68816d4a5d956efc0cae8fec124e7 100644 (file)
@@ -119,7 +119,7 @@ void pseries::archive(archive_node &n) const
 DEFAULT_UNARCHIVE(pseries)
 
 //////////
-// functions overriding virtual functions from bases classes
+// functions overriding virtual functions from base classes
 //////////
 
 void pseries::print(const print_context & c, unsigned level) const
@@ -132,7 +132,8 @@ void pseries::print(const print_context & c, unsigned level) const
                    << std::hex << ", hash=0x" << hashvalue << ", flags=0x" << flags << std::dec
                    << std::endl;
                unsigned delta_indent = static_cast<const print_tree &>(c).delta_indent;
-               for (unsigned i=0; i<seq.size(); ++i) {
+               unsigned num = seq.size();
+               for (unsigned i=0; i<num; ++i) {
                        seq[i].rest.print(c, level + delta_indent);
                        seq[i].coeff.print(c, level + delta_indent);
                        c.s << std::string(level + delta_indent, ' ') << "-----" << std::endl;
@@ -150,9 +151,10 @@ void pseries::print(const print_context & c, unsigned level) const
                
                // objects of type pseries must not have any zero entries, so the
                // trivial (zero) pseries needs a special treatment here:
-               if (seq.size() == 0)
+               if (seq.empty())
                        c.s << '0';
-               for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
+               epvector::const_iterator i = seq.begin(), end = seq.end();
+               while (i != end) {
                        // print a sign, if needed
                        if (i != seq.begin())
                                c.s << '+';
@@ -196,6 +198,7 @@ void pseries::print(const print_context & c, unsigned level) const
                                }
                        } else
                                Order(power(var-point,i->coeff)).print(c);
+                       ++i;
                }
 
                if (precedence() <= level)
@@ -263,7 +266,7 @@ int pseries::degree(const ex &s) const
        if (var.is_equal(s)) {
                // Return last exponent
                if (seq.size())
-                       return ex_to<numeric>((*(seq.end() - 1)).coeff).to_int();
+                       return ex_to<numeric>((seq.end()-1)->coeff).to_int();
                else
                        return 0;
        } else {
@@ -291,7 +294,7 @@ int pseries::ldegree(const ex &s) const
        if (var.is_equal(s)) {
                // Return first exponent
                if (seq.size())
-                       return ex_to<numeric>((*(seq.begin())).coeff).to_int();
+                       return ex_to<numeric>((seq.begin())->coeff).to_int();
                else
                        return 0;
        } else {
@@ -319,7 +322,7 @@ int pseries::ldegree(const ex &s) const
 ex pseries::coeff(const ex &s, int n) const
 {
        if (var.is_equal(s)) {
-               if (seq.size() == 0)
+               if (seq.empty())
                        return _ex0();
                
                // Binary search in sequence for given power
@@ -353,7 +356,7 @@ ex pseries::collect(const ex &s, bool distributed) const
        return *this;
 }
 
-/** Evaluate coefficients. */
+/** Perform coefficient-wise automatic term rewriting rules in this class. */
 ex pseries::eval(int level) const
 {
        if (level == 1)
@@ -418,13 +421,15 @@ ex pseries::subs(const lst & ls, const lst & lr, bool no_pattern) const
 ex pseries::expand(unsigned options) const
 {
        epvector newseq;
-       for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
+       epvector::const_iterator i = seq.begin(), end = seq.end();
+       while (i != end) {
                ex restexp = i->rest.expand();
                if (!restexp.is_zero())
                        newseq.push_back(expair(restexp, i->coeff));
+               ++i;
        }
        return (new pseries(relational(var,point), newseq))
-               ->setflag(status_flags::dynallocated | status_flags::expanded);
+               ->setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));
 }
 
 /** Implementation of ex::diff() for a power series.  It treats the series as a
@@ -471,7 +476,7 @@ ex pseries::convert_to_poly(bool no_order) const
 
 bool pseries::is_terminating(void) const
 {
-       return seq.size() == 0 || !is_order_function((seq.end()-1)->rest);
+       return seq.empty() || !is_order_function((seq.end()-1)->rest);
 }
 
 
@@ -677,7 +682,6 @@ ex pseries::mul_series(const pseries &other) const
        
        // Series multiplication
        epvector new_seq;
-       
        int a_max = degree(var);
        int b_max = other.degree(var);
        int a_min = ldegree(var);
@@ -718,30 +722,25 @@ ex pseries::mul_series(const pseries &other) const
  *  @see ex::series */
 ex mul::series(const relational & r, int order, unsigned options) const
 {
-       ex acc; // Series accumulator
-       
-       // Get first term from overall_coeff
-       acc = overall_coeff.series(r, order, options);
-       
+       pseries acc; // Series accumulator
+
        // Multiply with remaining terms
-       epvector::const_iterator it = seq.begin();
-       epvector::const_iterator itend = seq.end();
-       for (; it!=itend; ++it) {
+       const epvector::const_iterator itbeg = seq.begin();
+       const epvector::const_iterator itend = seq.end();
+       for (epvector::const_iterator it=itbeg; it!=itend; ++it) {
                ex op = it->rest;
-               if (op.info(info_flags::numeric)) {
-                       // series * const (special case, faster)
-                       ex f = power(op, it->coeff);
-                       acc = ex_to<pseries>(acc).mul_const(ex_to<numeric>(f));
-                       continue;
-               } else if (!is_ex_exactly_of_type(op, pseries))
+               if (!is_ex_exactly_of_type(op, pseries))
                        op = op.series(r, order, options);
                if (!it->coeff.is_equal(_ex1()))
                        op = ex_to<pseries>(op).power_const(ex_to<numeric>(it->coeff), order);
 
                // Series multiplication
-               acc = ex_to<pseries>(acc).mul_series(ex_to<pseries>(op));
+               if (it==itbeg)
+                       acc = ex_to<pseries>(op);
+               else
+                       acc = ex_to<pseries>(acc.mul_series(ex_to<pseries>(op)));
        }
-       return acc;
+       return acc.mul_const(ex_to<numeric>(overall_coeff));
 }
 
 
@@ -752,6 +751,7 @@ ex mul::series(const relational & r, int order, unsigned options) const
 ex pseries::power_const(const numeric &p, int deg) const
 {
        // method:
+       // (due to Leonhard Euler)
        // let A(x) be this series and for the time being let it start with a
        // constant (later we'll generalize):
        //     A(x) = a_0 + a_1*x + a_2*x^2 + ...
@@ -771,18 +771,20 @@ ex pseries::power_const(const numeric &p, int deg) const
        // repeat the above derivation.  The leading power of C2(x) = A2(x)^2 is
        // then of course x^(p*m) but the recurrence formula still holds.
        
-       if (seq.size()==0) {
-               // as a spacial case, handle the empty (zero) series honoring the
+       if (seq.empty()) {
+               // as a special case, handle the empty (zero) series honoring the
                // usual power laws such as implemented in power::eval()
                if (p.real().is_zero())
-                       throw (std::domain_error("pseries::power_const(): pow(0,I) is undefined"));
+                       throw std::domain_error("pseries::power_const(): pow(0,I) is undefined");
                else if (p.real().is_negative())
-                       throw (pole_error("pseries::power_const(): division by zero",1));
+                       throw pole_error("pseries::power_const(): division by zero",1);
                else
                        return *this;
        }
        
-       int ldeg = ldegree(var);
+       const int ldeg = ldegree(var);
+       if (!(p*ldeg).is_integer())
+               throw std::runtime_error("pseries::power_const(): trying to assemble a Puiseux series");
        
        // Compute coefficients of the powered series
        exvector co;
@@ -801,7 +803,7 @@ ex pseries::power_const(const numeric &p, int deg) const
                }
                if (!sum.is_zero())
                        all_sums_zero = false;
-               co.push_back(sum / coeff(var, ldeg) / numeric(i));
+               co.push_back(sum / coeff(var, ldeg) / i);
        }
        
        // Construct new series (of non-zero coefficients)
@@ -809,14 +811,14 @@ ex pseries::power_const(const numeric &p, int deg) const
        bool higher_order = false;
        for (int i=0; i<deg; ++i) {
                if (!co[i].is_zero())
-                       new_seq.push_back(expair(co[i], numeric(i) + p * ldeg));
+                       new_seq.push_back(expair(co[i], p * ldeg + i));
                if (is_order_function(co[i])) {
                        higher_order = true;
                        break;
                }
        }
        if (!higher_order && !all_sums_zero)
-               new_seq.push_back(expair(Order(_ex1()), numeric(deg) + p * ldeg));
+               new_seq.push_back(expair(Order(_ex1()), p * ldeg + deg));
        return pseries(relational(var,point), new_seq);
 }
 
@@ -824,9 +826,12 @@ ex pseries::power_const(const numeric &p, int deg) const
 /** Return a new pseries object with the powers shifted by deg. */
 pseries pseries::shift_exponents(int deg) const
 {
-       epvector newseq(seq);
-       for (epvector::iterator i=newseq.begin(); i!=newseq.end(); ++i)
-               i->coeff = i->coeff + deg;
+       epvector newseq = seq;
+       epvector::iterator i = newseq.begin(), end  = newseq.end();
+       while (i != end) {
+               i->coeff += deg;
+               ++i;
+       }
        return pseries(relational(var, point), newseq);
 }