]> www.ginac.de Git - ginac.git/blobdiff - ginac/power.cpp
documentation update
[ginac.git] / ginac / power.cpp
index 2b6049ba4f3eb90dbf787ddcb6818c6d889de7c1..b0f9cd2d293aad258475067ee4693a820e671f9a 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
 
 /*
- *  GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2001 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
 #include "debugmsg.h"
 #include "utils.h"
 
-#ifndef NO_NAMESPACE_GINAC
 namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
 
 GINAC_IMPLEMENT_REGISTERED_CLASS(power, basic)
 
 typedef std::vector<int> intvector;
 
 //////////
-// default constructor, destructor, copy constructor assignment operator and helpers
+// default ctor, dtor, copy ctor assignment operator and helpers
 //////////
 
 // public
 
 power::power() : basic(TINFO_power)
 {
-       debugmsg("power default constructor",LOGLEVEL_CONSTRUCT);
-}
-
-power::~power()
-{
-       debugmsg("power destructor",LOGLEVEL_DESTRUCT);
-       destroy(0);
-}
-
-power::power(const power & other)
-{
-       debugmsg("power copy constructor",LOGLEVEL_CONSTRUCT);
-       copy(other);
-}
-
-const power & power::operator=(const power & other)
-{
-       debugmsg("power operator=",LOGLEVEL_ASSIGNMENT);
-       if (this != &other) {
-               destroy(1);
-               copy(other);
-       }
-       return *this;
+       debugmsg("power default ctor",LOGLEVEL_CONSTRUCT);
 }
 
 // protected
@@ -82,8 +58,8 @@ const power & power::operator=(const power & other)
 void power::copy(const power & other)
 {
        inherited::copy(other);
-       basis=other.basis;
-       exponent=other.exponent;
+       basis = other.basis;
+       exponent = other.exponent;
 }
 
 void power::destroy(bool call_parent)
@@ -92,20 +68,20 @@ void power::destroy(bool call_parent)
 }
 
 //////////
-// other constructors
+// other ctors
 //////////
 
 // public
 
 power::power(const ex & lh, const ex & rh) : basic(TINFO_power), basis(lh), exponent(rh)
 {
-       debugmsg("power constructor from ex,ex",LOGLEVEL_CONSTRUCT);
+       debugmsg("power ctor from ex,ex",LOGLEVEL_CONSTRUCT);
        GINAC_ASSERT(basis.return_type()==return_types::commutative);
 }
 
 power::power(const ex & lh, const numeric & rh) : basic(TINFO_power), basis(lh), exponent(rh)
 {
-       debugmsg("power constructor from ex,numeric",LOGLEVEL_CONSTRUCT);
+       debugmsg("power ctor from ex,numeric",LOGLEVEL_CONSTRUCT);
        GINAC_ASSERT(basis.return_type()==return_types::commutative);
 }
 
@@ -116,7 +92,7 @@ power::power(const ex & lh, const numeric & rh) : basic(TINFO_power), basis(lh),
 /** Construct object from archive_node. */
 power::power(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
 {
-       debugmsg("power constructor from archive_node", LOGLEVEL_CONSTRUCT);
+       debugmsg("power ctor from archive_node", LOGLEVEL_CONSTRUCT);
        n.find_ex("basis", basis, sym_lst);
        n.find_ex("exponent", exponent, sym_lst);
 }
@@ -141,12 +117,6 @@ void power::archive(archive_node &n) const
 
 // public
 
-basic * power::duplicate() const
-{
-       debugmsg("power duplicate",LOGLEVEL_DUPLICATE);
-       return new power(*this);
-}
-
 void power::print(std::ostream & os, unsigned upper_precedence) const
 {
        debugmsg("power print",LOGLEVEL_PRINT);
@@ -165,7 +135,7 @@ void power::printraw(std::ostream & os) const
 {
        debugmsg("power printraw",LOGLEVEL_PRINT);
 
-       os << "power(";
+       os << class_name() << "(";
        basis.printraw(os);
        os << ",";
        exponent.printraw(os);
@@ -176,8 +146,8 @@ void power::printtree(std::ostream & os, unsigned indent) const
 {
        debugmsg("power printtree",LOGLEVEL_PRINT);
 
-       os << std::string(indent,' ') << "power: "
-          << "hash=" << hashvalue
+       os << std::string(indent,' ') << class_name()
+          << "hash=" << hashvalue
           << " (0x" << std::hex << hashvalue << std::dec << ")"
           << ", flags=" << flags << std::endl;
        basis.printtree(os, indent+delta_indent);
@@ -186,7 +156,9 @@ void power::printtree(std::ostream & os, unsigned indent) const
 
 static void print_sym_pow(std::ostream & os, unsigned type, const symbol &x, int exp)
 {
-       // Optimal output of integer powers of symbols to aid compiler CSE
+       // Optimal output of integer powers of symbols to aid compiler CSE.
+       // C.f. ISO/IEC 14882:1998, section 1.9 [intro execution], paragraph 15
+       // to learn why such a hack is really necessary.
        if (exp == 1) {
                x.printcsrc(os, type, 0);
        } else if (exp == 2) {
@@ -211,9 +183,8 @@ void power::printcsrc(std::ostream & os, unsigned type, unsigned upper_precedenc
        debugmsg("power print csrc", LOGLEVEL_PRINT);
        
        // Integer powers of symbols are printed in a special, optimized way
-       if (exponent.info(info_flags::integer) &&
-               (is_ex_exactly_of_type(basis, symbol) ||
-                is_ex_exactly_of_type(basis, constant))) {
+       if (exponent.info(info_flags::integer)
+        && (is_ex_exactly_of_type(basis, symbol) || is_ex_exactly_of_type(basis, constant))) {
                int exp = ex_to_numeric(exponent).to_int();
                if (exp > 0)
                        os << "(";
@@ -283,9 +254,12 @@ ex & power::let_op(int i)
 int power::degree(const symbol & s) const
 {
        if (is_exactly_of_type(*exponent.bp,numeric)) {
-               if ((*basis.bp).compare(s)==0)
-                       return ex_to_numeric(exponent).to_int();
-               else
+               if ((*basis.bp).compare(s)==0) {
+                       if (ex_to_numeric(exponent).is_integer())
+                               return ex_to_numeric(exponent).to_int();
+                       else
+                               return 0;
+               } else
                        return basis.degree(s) * ex_to_numeric(exponent).to_int();
        }
        return 0;
@@ -294,9 +268,12 @@ int power::degree(const symbol & s) const
 int power::ldegree(const symbol & s) const 
 {
        if (is_exactly_of_type(*exponent.bp,numeric)) {
-               if ((*basis.bp).compare(s)==0)
-                       return ex_to_numeric(exponent).to_int();
-               else
+               if ((*basis.bp).compare(s)==0) {
+                       if (ex_to_numeric(exponent).is_integer())
+                               return ex_to_numeric(exponent).to_int();
+                       else
+                               return 0;
+               } else
                        return basis.ldegree(s) * ex_to_numeric(exponent).to_int();
        }
        return 0;
@@ -306,17 +283,27 @@ ex power::coeff(const symbol & s, int n) const
 {
        if ((*basis.bp).compare(s)!=0) {
                // basis not equal to s
-               if (n==0) {
+               if (n == 0)
                        return *this;
-               } else {
+               else
                        return _ex0();
+       } else {
+               // basis equal to s
+               if (is_exactly_of_type(*exponent.bp, numeric) && ex_to_numeric(exponent).is_integer()) {
+                       // integer exponent
+                       int int_exp = ex_to_numeric(exponent).to_int();
+                       if (n == int_exp)
+                               return _ex1();
+                       else
+                               return _ex0();
+               } else {
+                       // non-integer exponents are treated as zero
+                       if (n == 0)
+                               return *this;
+                       else
+                               return _ex0();
                }
-       } else if (is_exactly_of_type(*exponent.bp,numeric)&&
-                          (static_cast<const numeric &>(*exponent.bp).compare(numeric(n))==0)) {
-               return _ex1();
        }
-
-       return _ex0();
 }
 
 ex power::eval(int level) const
@@ -356,11 +343,12 @@ ex power::eval(int level) const
        }
        
        // ^(x,0) -> 1 (0^0 also handled here)
-       if (eexponent.is_zero())
+       if (eexponent.is_zero()) {
                if (ebasis.is_zero())
                        throw (std::domain_error("power::eval(): pow(0,0) is undefined"));
                else
                        return _ex1();
+       }
        
        // ^(x,1) -> x
        if (eexponent.is_equal(_ex1()))
@@ -385,7 +373,7 @@ ex power::eval(int level) const
                // except if c1,c2 are rational, but c1^c2 is not)
                bool basis_is_crational = num_basis->is_crational();
                bool exponent_is_crational = num_exponent->is_crational();
-               numeric res = (*num_basis).power(*num_exponent);
+               numeric res = num_basis->power(*num_exponent);
                
                if ((!basis_is_crational || !exponent_is_crational)
                        || res.is_crational()) {
@@ -409,7 +397,7 @@ ex power::eval(int level) const
                        else {
                                epvector res;
                                res.push_back(expair(ebasis,r.div(m)));
-                               return (new mul(res,ex(num_basis->power(q))))->setflag(status_flags::dynallocated | status_flags::evaluated);
+                               return (new mul(res,ex(num_basis->power_dyn(q))))->setflag(status_flags::dynallocated | status_flags::evaluated);
                        }
                }
        }
@@ -424,9 +412,8 @@ ex power::eval(int level) const
                if (is_ex_exactly_of_type(sub_exponent,numeric)) {
                        const numeric & num_sub_exponent = ex_to_numeric(sub_exponent);
                        GINAC_ASSERT(num_sub_exponent!=numeric(1));
-                       if (num_exponent->is_integer() || abs(num_sub_exponent)<1) {
+                       if (num_exponent->is_integer() || abs(num_sub_exponent)<1)
                                return power(sub_basis,num_sub_exponent.mul(*num_exponent));
-                       }
                }
        }
        
@@ -440,34 +427,32 @@ ex power::eval(int level) const
        // ^(*(...,x,c1),c2) -> ^(*(...,x;-1),c2)*(-c1)^c2 (c1, c2 numeric(), c1<0)
        if (exponent_is_numerical && is_ex_exactly_of_type(ebasis,mul)) {
                GINAC_ASSERT(!num_exponent->is_integer()); // should have been handled above
-               const mul & mulref=ex_to_mul(ebasis);
+               const mul & mulref = ex_to_mul(ebasis);
                if (!mulref.overall_coeff.is_equal(_ex1())) {
-                       const numeric & num_coeff=ex_to_numeric(mulref.overall_coeff);
+                       const numeric & num_coeff = ex_to_numeric(mulref.overall_coeff);
                        if (num_coeff.is_real()) {
-                               if (num_coeff.is_positive()>0) {
-                                       mul * mulp=new mul(mulref);
-                                       mulp->overall_coeff=_ex1();
+                               if (num_coeff.is_positive()) {
+                                       mul * mulp = new mul(mulref);
+                                       mulp->overall_coeff = _ex1();
                                        mulp->clearflag(status_flags::evaluated);
                                        mulp->clearflag(status_flags::hash_calculated);
                                        return (new mul(power(*mulp,exponent),
-                                                                       power(num_coeff,*num_exponent)))->
-                                               setflag(status_flags::dynallocated);
+                                                       power(num_coeff,*num_exponent)))->setflag(status_flags::dynallocated);
                                } else {
                                        GINAC_ASSERT(num_coeff.compare(_num0())<0);
                                        if (num_coeff.compare(_num_1())!=0) {
-                                               mul * mulp=new mul(mulref);
-                                               mulp->overall_coeff=_ex_1();
+                                               mul * mulp = new mul(mulref);
+                                               mulp->overall_coeff = _ex_1();
                                                mulp->clearflag(status_flags::evaluated);
                                                mulp->clearflag(status_flags::hash_calculated);
                                                return (new mul(power(*mulp,exponent),
-                                                                               power(abs(num_coeff),*num_exponent)))->
-                                                       setflag(status_flags::dynallocated);
+                                                               power(abs(num_coeff),*num_exponent)))->setflag(status_flags::dynallocated);
                                        }
                                }
                        }
                }
        }
-               
+       
        if (are_ex_trivially_equal(ebasis,basis) &&
                are_ex_trivially_equal(eexponent,exponent)) {
                return this->hold();
@@ -532,9 +517,9 @@ ex power::derivative(const symbol & s) const
                return mul(newseq, exponent);
        } else {
                // D(b^e) = b^e * (D(e)*ln(b) + e*D(b)/b)
-               return mul(power(basis, exponent),
-                                  add(mul(exponent.diff(s), log(basis)),
-                                          mul(mul(exponent, basis.diff(s)), power(basis, -1))));
+               return mul(*this,
+                          add(mul(exponent.diff(s), log(basis)),
+                          mul(mul(exponent, basis.diff(s)), power(basis, _ex_1()))));
        }
 }
 
@@ -567,38 +552,62 @@ ex power::expand(unsigned options) const
                return *this;
        
        ex expanded_basis = basis.expand(options);
+       ex expanded_exponent = exponent.expand(options);
        
-       if (!is_ex_exactly_of_type(exponent,numeric) ||
-               !ex_to_numeric(exponent).is_integer()) {
-               if (are_ex_trivially_equal(basis,expanded_basis)) {
+       // x^(a+b) -> x^a * x^b
+       if (is_ex_exactly_of_type(expanded_exponent, add)) {
+               const add &a = ex_to_add(expanded_exponent);
+               exvector distrseq;
+               distrseq.reserve(a.seq.size() + 1);
+               epvector::const_iterator last = a.seq.end();
+               epvector::const_iterator cit = a.seq.begin();
+               while (cit!=last) {
+                       distrseq.push_back(power(expanded_basis, a.recombine_pair_to_ex(*cit)));
+                       cit++;
+               }
+               
+               // Make sure that e.g. (x+y)^(2+a) expands the (x+y)^2 factor
+               if (ex_to_numeric(a.overall_coeff).is_integer()) {
+                       const numeric &num_exponent = ex_to_numeric(a.overall_coeff);
+                       int int_exponent = num_exponent.to_int();
+                       if (int_exponent > 0 && is_ex_exactly_of_type(expanded_basis, add))
+                               distrseq.push_back(expand_add(ex_to_add(expanded_basis), int_exponent));
+                       else
+                               distrseq.push_back(power(expanded_basis, a.overall_coeff));
+               } else
+                       distrseq.push_back(power(expanded_basis, a.overall_coeff));
+               
+               // Make sure that e.g. (x+y)^(1+a) -> x*(x+y)^a + y*(x+y)^a
+               ex r = (new mul(distrseq))->setflag(status_flags::dynallocated);
+               return r.expand();
+       }
+       
+       if (!is_ex_exactly_of_type(expanded_exponent, numeric) ||
+               !ex_to_numeric(expanded_exponent).is_integer()) {
+               if (are_ex_trivially_equal(basis,expanded_basis) && are_ex_trivially_equal(exponent,expanded_exponent)) {
                        return this->hold();
                } else {
-                       return (new power(expanded_basis,exponent))->
-                               setflag(status_flags::dynallocated |
-                                               status_flags::expanded);
+                       return (new power(expanded_basis,expanded_exponent))->setflag(status_flags::dynallocated | status_flags::expanded);
                }
        }
        
        // integer numeric exponent
-       const numeric & num_exponent = ex_to_numeric(exponent);
+       const numeric & num_exponent = ex_to_numeric(expanded_exponent);
        int int_exponent = num_exponent.to_int();
        
-       if (int_exponent > 0 && is_ex_exactly_of_type(expanded_basis,add)) {
+       // (x+y)^n, n>0
+       if (int_exponent > 0 && is_ex_exactly_of_type(expanded_basis,add))
                return expand_add(ex_to_add(expanded_basis), int_exponent);
-       }
        
-       if (is_ex_exactly_of_type(expanded_basis,mul)) {
+       // (x*y)^n -> x^n * y^n
+       if (is_ex_exactly_of_type(expanded_basis,mul))
                return expand_mul(ex_to_mul(expanded_basis), num_exponent);
-       }
        
        // cannot expand further
-       if (are_ex_trivially_equal(basis,expanded_basis)) {
+       if (are_ex_trivially_equal(basis,expanded_basis) && are_ex_trivially_equal(exponent,expanded_exponent))
                return this->hold();
-       } else {
-               return (new power(expanded_basis,exponent))->
-                          setflag(status_flags::dynallocated |
-                                          status_flags::expanded);
-       }
+       else
+               return (new power(expanded_basis,expanded_exponent))->setflag(status_flags::dynallocated | status_flags::expanded);
 }
 
 //////////
@@ -638,39 +647,37 @@ ex power::expand_add(const add & a, int n) const
                for (l=0; l<m-1; l++) {
                        const ex & b = a.op(l);
                        GINAC_ASSERT(!is_ex_exactly_of_type(b,add));
-                       GINAC_ASSERT(!is_ex_exactly_of_type(b,power)||
-                                                !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric)||
-                                                !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer()||
-                                                !is_ex_exactly_of_type(ex_to_power(b).basis,add)||
-                                                !is_ex_exactly_of_type(ex_to_power(b).basis,mul)||
-                                                !is_ex_exactly_of_type(ex_to_power(b).basis,power));
-                       if (is_ex_exactly_of_type(b,mul)) {
+                       GINAC_ASSERT(!is_ex_exactly_of_type(b,power) ||
+                                    !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric) ||
+                                    !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer() ||
+                                    !is_ex_exactly_of_type(ex_to_power(b).basis,add) ||
+                                    !is_ex_exactly_of_type(ex_to_power(b).basis,mul) ||
+                                    !is_ex_exactly_of_type(ex_to_power(b).basis,power));
+                       if (is_ex_exactly_of_type(b,mul))
                                term.push_back(expand_mul(ex_to_mul(b),numeric(k[l])));
-                       } else {
+                       else
                                term.push_back(power(b,k[l]));
-                       }
                }
                
                const ex & b = a.op(l);
                GINAC_ASSERT(!is_ex_exactly_of_type(b,add));
-               GINAC_ASSERT(!is_ex_exactly_of_type(b,power)||
-                                        !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric)||
-                                        !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer()||
-                                        !is_ex_exactly_of_type(ex_to_power(b).basis,add)||
-                                        !is_ex_exactly_of_type(ex_to_power(b).basis,mul)||
-                                        !is_ex_exactly_of_type(ex_to_power(b).basis,power));
-               if (is_ex_exactly_of_type(b,mul)) {
+               GINAC_ASSERT(!is_ex_exactly_of_type(b,power) ||
+                            !is_ex_exactly_of_type(ex_to_power(b).exponent,numeric) ||
+                            !ex_to_numeric(ex_to_power(b).exponent).is_pos_integer() ||
+                            !is_ex_exactly_of_type(ex_to_power(b).basis,add) ||
+                            !is_ex_exactly_of_type(ex_to_power(b).basis,mul) ||
+                            !is_ex_exactly_of_type(ex_to_power(b).basis,power));
+               if (is_ex_exactly_of_type(b,mul))
                        term.push_back(expand_mul(ex_to_mul(b),numeric(n-k_cum[m-2])));
-               } else {
+               else
                        term.push_back(power(b,n-k_cum[m-2]));
-               }
                
                numeric f = binomial(numeric(n),numeric(k[0]));
-               for (l=1; l<m-1; l++) {
-                       f=f*binomial(numeric(n-k_cum[l-1]),numeric(k[l]));
-               }
+               for (l=1; l<m-1; l++)
+                       f *= binomial(numeric(n-k_cum[l-1]),numeric(k[l]));
+               
                term.push_back(f);
-
+               
                /*
                cout << "begin term" << endl;
                for (int i=0; i<m-1; i++) {
@@ -683,31 +690,29 @@ ex power::expand_add(const add & a, int n) const
                }
                cout << "end term" << endl;
                */
-
+               
                // TODO: optimize this
                sum.push_back((new mul(term))->setflag(status_flags::dynallocated));
                
                // increment k[]
-               l=m-2;
+               l = m-2;
                while ((l>=0)&&((++k[l])>upper_limit[l])) {
-                       k[l]=0;    
+                       k[l] = 0;    
                        l--;
                }
                if (l<0) break;
-
+               
                // recalc k_cum[] and upper_limit[]
-               if (l==0) {
-                       k_cum[0]=k[0];
-               } else {
-                       k_cum[l]=k_cum[l-1]+k[l];
-               }
-               for (int i=l+1; i<m-1; i++) {
-                       k_cum[i]=k_cum[i-1]+k[i];
-               }
-
-               for (int i=l+1; i<m-1; i++) {
-                       upper_limit[i]=n-k_cum[i-1];
-               }   
+               if (l==0)
+                       k_cum[0] = k[0];
+               else
+                       k_cum[l] = k_cum[l-1]+k[l];
+               
+               for (int i=l+1; i<m-1; i++)
+                       k_cum[i] = k_cum[i-1]+k[i];
+               
+               for (int i=l+1; i<m-1; i++)
+                       upper_limit[i] = n-k_cum[i-1];
        }
        return (new add(sum))->setflag(status_flags::dynallocated |
                                                                   status_flags::expanded );
@@ -719,70 +724,70 @@ ex power::expand_add(const add & a, int n) const
 ex power::expand_add_2(const add & a) const
 {
        epvector sum;
-       unsigned a_nops=a.nops();
+       unsigned a_nops = a.nops();
        sum.reserve((a_nops*(a_nops+1))/2);
-       epvector::const_iterator last=a.seq.end();
-
+       epvector::const_iterator last = a.seq.end();
+       
        // power(+(x,...,z;c),2)=power(+(x,...,z;0),2)+2*c*+(x,...,z;0)+c*c
        // first part: ignore overall_coeff and expand other terms
        for (epvector::const_iterator cit0=a.seq.begin(); cit0!=last; ++cit0) {
-               const ex & r=(*cit0).rest;
-               const ex & c=(*cit0).coeff;
+               const ex & r = (*cit0).rest;
+               const ex & c = (*cit0).coeff;
                
                GINAC_ASSERT(!is_ex_exactly_of_type(r,add));
-               GINAC_ASSERT(!is_ex_exactly_of_type(r,power)||
-                          !is_ex_exactly_of_type(ex_to_power(r).exponent,numeric)||
-                          !ex_to_numeric(ex_to_power(r).exponent).is_pos_integer()||
-                          !is_ex_exactly_of_type(ex_to_power(r).basis,add)||
-                          !is_ex_exactly_of_type(ex_to_power(r).basis,mul)||
-                          !is_ex_exactly_of_type(ex_to_power(r).basis,power));
-
+               GINAC_ASSERT(!is_ex_exactly_of_type(r,power) ||
+                            !is_ex_exactly_of_type(ex_to_power(r).exponent,numeric) ||
+                            !ex_to_numeric(ex_to_power(r).exponent).is_pos_integer() ||
+                            !is_ex_exactly_of_type(ex_to_power(r).basis,add) ||
+                            !is_ex_exactly_of_type(ex_to_power(r).basis,mul) ||
+                            !is_ex_exactly_of_type(ex_to_power(r).basis,power));
+               
                if (are_ex_trivially_equal(c,_ex1())) {
                        if (is_ex_exactly_of_type(r,mul)) {
-                               sum.push_back(expair(expand_mul(ex_to_mul(r),_num2()),_ex1()));
+                               sum.push_back(expair(expand_mul(ex_to_mul(r),_num2()),
+                                                    _ex1()));
                        } else {
                                sum.push_back(expair((new power(r,_ex2()))->setflag(status_flags::dynallocated),
-                                                                        _ex1()));
+                                                    _ex1()));
                        }
                } else {
                        if (is_ex_exactly_of_type(r,mul)) {
                                sum.push_back(expair(expand_mul(ex_to_mul(r),_num2()),
-                                                                        ex_to_numeric(c).power_dyn(_num2())));
+                                                    ex_to_numeric(c).power_dyn(_num2())));
                        } else {
                                sum.push_back(expair((new power(r,_ex2()))->setflag(status_flags::dynallocated),
-                                                                        ex_to_numeric(c).power_dyn(_num2())));
+                                                    ex_to_numeric(c).power_dyn(_num2())));
                        }
                }
                        
                for (epvector::const_iterator cit1=cit0+1; cit1!=last; ++cit1) {
-                       const ex & r1=(*cit1).rest;
-                       const ex & c1=(*cit1).coeff;
+                       const ex & r1 = (*cit1).rest;
+                       const ex & c1 = (*cit1).coeff;
                        sum.push_back(a.combine_ex_with_coeff_to_pair((new mul(r,r1))->setflag(status_flags::dynallocated),
-                                                                                                                 _num2().mul(ex_to_numeric(c)).mul_dyn(ex_to_numeric(c1))));
+                                                                     _num2().mul(ex_to_numeric(c)).mul_dyn(ex_to_numeric(c1))));
                }
        }
-
+       
        GINAC_ASSERT(sum.size()==(a.seq.size()*(a.seq.size()+1))/2);
-
+       
        // second part: add terms coming from overall_factor (if != 0)
-       if (!a.overall_coeff.is_equal(_ex0())) {
+       if (!a.overall_coeff.is_zero()) {
                for (epvector::const_iterator cit=a.seq.begin(); cit!=a.seq.end(); ++cit) {
                        sum.push_back(a.combine_pair_with_coeff_to_pair(*cit,ex_to_numeric(a.overall_coeff).mul_dyn(_num2())));
                }
                sum.push_back(expair(ex_to_numeric(a.overall_coeff).power_dyn(_num2()),_ex1()));
        }
-               
+       
        GINAC_ASSERT(sum.size()==(a_nops*(a_nops+1))/2);
        
-       return (new add(sum))->setflag(status_flags::dynallocated |
-                                                                  status_flags::expanded );
+       return (new add(sum))->setflag(status_flags::dynallocated | status_flags::expanded);
 }
 
 /** Expand factors of m in m^n where m is a mul and n is and integer
  *  @see power::expand */
 ex power::expand_mul(const mul & m, const numeric & n) const
 {
-       if (n.is_equal(_num0()))
+       if (n.is_zero())
                return _ex1();
        
        epvector distrseq;
@@ -795,18 +800,16 @@ ex power::expand_mul(const mul & m, const numeric & n) const
                } else {
                        // it is safe not to call mul::combine_pair_with_coeff_to_pair()
                        // since n is an integer
-                       distrseq.push_back(expair((*cit).rest,
-                                                                         ex_to_numeric((*cit).coeff).mul(n)));
+                       distrseq.push_back(expair((*cit).rest, ex_to_numeric((*cit).coeff).mul(n)));
                }
                ++cit;
        }
-       return (new mul(distrseq,ex_to_numeric(m.overall_coeff).power_dyn(n)))
-               ->setflag(status_flags::dynallocated);
+       return (new mul(distrseq,ex_to_numeric(m.overall_coeff).power_dyn(n)))->setflag(status_flags::dynallocated);
 }
 
 /*
 ex power::expand_commutative_3(const ex & basis, const numeric & exponent,
-                                                        unsigned options) const
+                               unsigned options) const
 {
        // obsolete
 
@@ -822,12 +825,10 @@ ex power::expand_commutative_3(const ex & basis, const numeric & exponent,
        
        int n=exponent.to_int();
        for (int k=0; k<=n; k++) {
-               distrseq.push_back(binomial(n,k)*power(first_operands,numeric(k))*
-                                                  power(last_operand,numeric(n-k)));
+               distrseq.push_back(binomial(n,k) * power(first_operands,numeric(k))
+                                                * power(last_operand,numeric(n-k)));
        }
-       return ex((new add(distrseq))->setflag(status_flags::expanded |
-                                                                                  status_flags::dynallocated )).
-                  expand(options);
+       return ex((new add(distrseq))->setflag(status_flags::expanded | status_flags::dynallocated)).expand(options);
 }
 */
 
@@ -835,11 +836,11 @@ ex power::expand_commutative_3(const ex & basis, const numeric & exponent,
 ex power::expand_noncommutative(const ex & basis, const numeric & exponent,
                                                                unsigned options) const
 {
-       ex rest_power=ex(power(basis,exponent.add(_num_1()))).
-                                 expand(options | expand_options::internal_do_not_expand_power_operands);
+       ex rest_power = ex(power(basis,exponent.add(_num_1()))).
+                       expand(options | expand_options::internal_do_not_expand_power_operands);
 
        return ex(mul(rest_power,basis),0).
-                  expand(options | expand_options::internal_do_not_expand_mul_operands);
+              expand(options | expand_options::internal_do_not_expand_mul_operands);
 }
 */
 
@@ -851,13 +852,6 @@ ex power::expand_noncommutative(const ex & basis, const numeric & exponent,
 
 unsigned power::precedence = 60;
 
-//////////
-// global constants
-//////////
-
-const power some_power;
-const type_info & typeid_power=typeid(some_power);
-
 // helper function
 
 ex sqrt(const ex & a)
@@ -865,6 +859,4 @@ ex sqrt(const ex & a)
        return power(a,_ex1_2());
 }
 
-#ifndef NO_NAMESPACE_GINAC
 } // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC