]> www.ginac.de Git - ginac.git/blobdiff - ginac/normal.cpp
- fixed three little standard-conformance issues.
[ginac.git] / ginac / normal.cpp
index e9d883f53b12a74af830f2be921c7c8a6e3296ab..7a52c71d2914d331a0be314dd100a9e46dc155e6 100644 (file)
 #include "inifcns.h"
 #include "lst.h"
 #include "mul.h"
-#include "ncmul.h"
 #include "numeric.h"
 #include "power.h"
 #include "relational.h"
+#include "matrix.h"
 #include "pseries.h"
 #include "symbol.h"
 #include "utils.h"
@@ -155,11 +155,11 @@ typedef std::vector<sym_desc> sym_desc_vec;
 // Add symbol the sym_desc_vec (used internally by get_symbol_stats())
 static void add_symbol(const symbol *s, sym_desc_vec &v)
 {
-       sym_desc_vec::iterator it = v.begin(), itend = v.end();
+       sym_desc_vec::const_iterator it = v.begin(), itend = v.end();
        while (it != itend) {
                if (it->sym->compare(*s) == 0)  // If it's already in there, don't add it a second time
                        return;
-               it++;
+               ++it;
        }
        sym_desc d;
        d.sym = s;
@@ -205,16 +205,16 @@ static void get_symbol_stats(const ex &a, const ex &b, sym_desc_vec &v)
                it->max_lcnops = std::max(a.lcoeff(*(it->sym)).nops(), b.lcoeff(*(it->sym)).nops());
                it->ldeg_a = a.ldegree(*(it->sym));
                it->ldeg_b = b.ldegree(*(it->sym));
-               it++;
+               ++it;
        }
-       sort(v.begin(), v.end());
+       std::sort(v.begin(), v.end());
 #if 0
        std::clog << "Symbols:\n";
        it = v.begin(); itend = v.end();
        while (it != itend) {
                std::clog << " " << *it->sym << ": deg_a=" << it->deg_a << ", deg_b=" << it->deg_b << ", ldeg_a=" << it->ldeg_a << ", ldeg_b=" << it->ldeg_b << ", max_deg=" << it->max_deg << ", max_lcnops=" << it->max_lcnops << endl;
                std::clog << "  lcoeff_a=" << a.lcoeff(*(it->sym)) << ", lcoeff_b=" << b.lcoeff(*(it->sym)) << endl;
-               it++;
+               ++it;
        }
 #endif
 }
@@ -229,7 +229,7 @@ static void get_symbol_stats(const ex &a, const ex &b, sym_desc_vec &v)
 static numeric lcmcoeff(const ex &e, const numeric &l)
 {
        if (e.info(info_flags::rational))
-               return lcm(ex_to_numeric(e).denom(), l);
+               return lcm(ex_to<numeric>(e).denom(), l);
        else if (is_ex_exactly_of_type(e, add)) {
                numeric c = _num1();
                for (unsigned i=0; i<e.nops(); i++)
@@ -244,7 +244,7 @@ static numeric lcmcoeff(const ex &e, const numeric &l)
                if (is_ex_exactly_of_type(e.op(0), symbol))
                        return l;
                else
-                       return pow(lcmcoeff(e.op(0), l), ex_to_numeric(e.op(1)));
+                       return pow(lcmcoeff(e.op(0), l), ex_to<numeric>(e.op(1)));
        }
        return l;
 }
@@ -269,25 +269,27 @@ static numeric lcm_of_coefficients_denominators(const ex &e)
 static ex multiply_lcm(const ex &e, const numeric &lcm)
 {
        if (is_ex_exactly_of_type(e, mul)) {
-               ex c = _ex1();
+               unsigned num = e.nops();
+               exvector v; v.reserve(num + 1);
                numeric lcm_accum = _num1();
                for (unsigned i=0; i<e.nops(); i++) {
                        numeric op_lcm = lcmcoeff(e.op(i), _num1());
-                       c *= multiply_lcm(e.op(i), op_lcm);
+                       v.push_back(multiply_lcm(e.op(i), op_lcm));
                        lcm_accum *= op_lcm;
                }
-               c *= lcm / lcm_accum;
-               return c;
+               v.push_back(lcm / lcm_accum);
+               return (new mul(v))->setflag(status_flags::dynallocated);
        } else if (is_ex_exactly_of_type(e, add)) {
-               ex c = _ex0();
-               for (unsigned i=0; i<e.nops(); i++)
-                       c += multiply_lcm(e.op(i), lcm);
-               return c;
+               unsigned num = e.nops();
+               exvector v; v.reserve(num);
+               for (unsigned i=0; i<num; i++)
+                       v.push_back(multiply_lcm(e.op(i), lcm));
+               return (new add(v))->setflag(status_flags::dynallocated);
        } else if (is_ex_exactly_of_type(e, power)) {
                if (is_ex_exactly_of_type(e.op(0), symbol))
                        return e * lcm;
                else
-                       return pow(multiply_lcm(e.op(0), lcm.power(ex_to_numeric(e.op(1)).inverse())), e.op(1));
+                       return pow(multiply_lcm(e.op(0), lcm.power(ex_to<numeric>(e.op(1)).inverse())), e.op(1));
        } else
                return e * lcm;
 }
@@ -322,11 +324,11 @@ numeric add::integer_content(void) const
        while (it != itend) {
                GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
                GINAC_ASSERT(is_ex_exactly_of_type(it->coeff,numeric));
-               c = gcd(ex_to_numeric(it->coeff), c);
+               c = gcd(ex_to<numeric>(it->coeff), c);
                it++;
        }
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       c = gcd(ex_to_numeric(overall_coeff),c);
+       c = gcd(ex_to<numeric>(overall_coeff),c);
        return c;
 }
 
@@ -341,7 +343,7 @@ numeric mul::integer_content(void) const
        }
 #endif // def DO_GINAC_ASSERT
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       return abs(ex_to_numeric(overall_coeff));
+       return abs(ex_to<numeric>(overall_coeff));
 }
 
 
@@ -372,7 +374,6 @@ ex quo(const ex &a, const ex &b, const symbol &x, bool check_args)
                throw(std::invalid_argument("quo: arguments must be polynomials over the rationals"));
 
        // Polynomial long division
-       ex q = _ex0();
        ex r = a.expand();
        if (r.is_zero())
                return r;
@@ -380,22 +381,23 @@ ex quo(const ex &a, const ex &b, const symbol &x, bool check_args)
        int rdeg = r.degree(x);
        ex blcoeff = b.expand().coeff(x, bdeg);
        bool blcoeff_is_numeric = is_ex_exactly_of_type(blcoeff, numeric);
+       exvector v; v.reserve(rdeg - bdeg + 1);
        while (rdeg >= bdeg) {
                ex term, rcoeff = r.coeff(x, rdeg);
                if (blcoeff_is_numeric)
                        term = rcoeff / blcoeff;
                else {
                        if (!divide(rcoeff, blcoeff, term, false))
-                               return *new ex(fail());
+                               return (new fail())->setflag(status_flags::dynallocated);
                }
                term *= power(x, rdeg - bdeg);
-               q += term;
+               v.push_back(term);
                r -= (term * b).expand();
                if (r.is_zero())
                        break;
                rdeg = r.degree(x);
        }
-       return q;
+       return (new add(v))->setflag(status_flags::dynallocated);
 }
 
 
@@ -416,7 +418,7 @@ ex rem(const ex &a, const ex &b, const symbol &x, bool check_args)
                if  (is_ex_exactly_of_type(b, numeric))
                        return _ex0();
                else
-                       return b;
+                       return a;
        }
 #if FAST_COMPARE
        if (a.is_equal(b))
@@ -439,7 +441,7 @@ ex rem(const ex &a, const ex &b, const symbol &x, bool check_args)
                        term = rcoeff / blcoeff;
                else {
                        if (!divide(rcoeff, blcoeff, term, false))
-                               return *new ex(fail());
+                               return (new fail())->setflag(status_flags::dynallocated);
                }
                term *= power(x, rdeg - bdeg);
                r -= (term * b).expand();
@@ -451,6 +453,24 @@ ex rem(const ex &a, const ex &b, const symbol &x, bool check_args)
 }
 
 
+/** Decompose rational function a(x)=N(x)/D(x) into P(x)+n(x)/D(x)
+ *  with degree(n, x) < degree(D, x).
+ *
+ *  @param a rational function in x
+ *  @param x a is a function of x
+ *  @return decomposed function. */
+ex decomp_rational(const ex &a, const symbol &x)
+{
+       ex nd = numer_denom(a);
+       ex numer = nd.op(0), denom = nd.op(1);
+       ex q = quo(numer, denom, x);
+       if (is_ex_exactly_of_type(q, fail))
+               return a;
+       else
+               return q + rem(numer, denom, x) / denom;
+}
+
+
 /** Pseudo-remainder of polynomials a(x) and b(x) in Z[x].
  *
  *  @param a  first polynomial in x (dividend)
@@ -511,7 +531,6 @@ ex prem(const ex &a, const ex &b, const symbol &x, bool check_args)
  *  @param check_args  check whether a and b are polynomials with rational
  *         coefficients (defaults to "true")
  *  @return sparse pseudo-remainder of a(x) and b(x) in Z[x] */
-
 ex sprem(const ex &a, const ex &b, const symbol &x, bool check_args)
 {
        if (b.is_zero())
@@ -598,6 +617,7 @@ bool divide(const ex &a, const ex &b, ex &q, bool check_args)
        int rdeg = r.degree(*x);
        ex blcoeff = b.expand().coeff(*x, bdeg);
        bool blcoeff_is_numeric = is_ex_exactly_of_type(blcoeff, numeric);
+       exvector v; v.reserve(rdeg - bdeg + 1);
        while (rdeg >= bdeg) {
                ex term, rcoeff = r.coeff(*x, rdeg);
                if (blcoeff_is_numeric)
@@ -606,10 +626,12 @@ bool divide(const ex &a, const ex &b, ex &q, bool check_args)
                        if (!divide(rcoeff, blcoeff, term, false))
                                return false;
                term *= power(*x, rdeg - bdeg);
-               q += term;
+               v.push_back(term);
                r -= (term * b).expand();
-               if (r.is_zero())
+               if (r.is_zero()) {
+                       q = (new add(v))->setflag(status_flags::dynallocated);
                        return true;
+               }
                rdeg = r.degree(*x);
        }
        return false;
@@ -756,14 +778,16 @@ static bool divide_in_z(const ex &a, const ex &b, ex &q, sym_desc_vec::const_ite
        int rdeg = adeg;
        ex eb = b.expand();
        ex blcoeff = eb.coeff(*x, bdeg);
+       exvector v; v.reserve(rdeg - bdeg + 1);
        while (rdeg >= bdeg) {
                ex term, rcoeff = r.coeff(*x, rdeg);
                if (!divide_in_z(rcoeff, blcoeff, term, var+1))
                        break;
                term = (term * power(*x, rdeg - bdeg)).expand();
-               q += term;
+               v.push_back(term);
                r -= (term * eb).expand();
                if (r.is_zero()) {
+                       q = (new add(v))->setflag(status_flags::dynallocated);
 #if USE_REMEMBER
                        dr_remember[ex2(a, b)] = exbool(q, true);
 #endif
@@ -1205,11 +1229,11 @@ numeric add::max_coefficient(void) const
        epvector::const_iterator it = seq.begin();
        epvector::const_iterator itend = seq.end();
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       numeric cur_max = abs(ex_to_numeric(overall_coeff));
+       numeric cur_max = abs(ex_to<numeric>(overall_coeff));
        while (it != itend) {
                numeric a;
                GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
-               a = abs(ex_to_numeric(it->coeff));
+               a = abs(ex_to<numeric>(it->coeff));
                if (a > cur_max)
                        cur_max = a;
                it++;
@@ -1228,7 +1252,7 @@ numeric mul::max_coefficient(void) const
        }
 #endif // def DO_GINAC_ASSERT
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       return abs(ex_to_numeric(overall_coeff));
+       return abs(ex_to<numeric>(overall_coeff));
 }
 
 
@@ -1263,13 +1287,13 @@ ex add::smod(const numeric &xi) const
        epvector::const_iterator itend = seq.end();
        while (it != itend) {
                GINAC_ASSERT(!is_ex_exactly_of_type(it->rest,numeric));
-               numeric coeff = GiNaC::smod(ex_to_numeric(it->coeff), xi);
+               numeric coeff = GiNaC::smod(ex_to<numeric>(it->coeff), xi);
                if (!coeff.is_zero())
                        newseq.push_back(expair(it->rest, coeff));
                it++;
        }
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       numeric coeff = GiNaC::smod(ex_to_numeric(overall_coeff), xi);
+       numeric coeff = GiNaC::smod(ex_to<numeric>(overall_coeff), xi);
        return (new add(newseq,coeff))->setflag(status_flags::dynallocated);
 }
 
@@ -1283,9 +1307,9 @@ ex mul::smod(const numeric &xi) const
                it++;
        }
 #endif // def DO_GINAC_ASSERT
-       mul * mulcopyp=new mul(*this);
+       mul * mulcopyp = new mul(*this);
        GINAC_ASSERT(is_ex_exactly_of_type(overall_coeff,numeric));
-       mulcopyp->overall_coeff = GiNaC::smod(ex_to_numeric(overall_coeff),xi);
+       mulcopyp->overall_coeff = GiNaC::smod(ex_to<numeric>(overall_coeff),xi);
        mulcopyp->clearflag(status_flags::evaluated);
        mulcopyp->clearflag(status_flags::hash_calculated);
        return mulcopyp->setflag(status_flags::dynallocated);
@@ -1293,17 +1317,17 @@ ex mul::smod(const numeric &xi) const
 
 
 /** xi-adic polynomial interpolation */
-static ex interpolate(const ex &gamma, const numeric &xi, const symbol &x)
+static ex interpolate(const ex &gamma, const numeric &xi, const symbol &x, int degree_hint = 1)
 {
-       ex g = _ex0();
+       exvector g; g.reserve(degree_hint);
        ex e = gamma;
        numeric rxi = xi.inverse();
        for (int i=0; !e.is_zero(); i++) {
                ex gi = e.smod(xi);
-               g += gi * power(x, i);
+               g.push_back(gi * power(x, i));
                e = (e - gi) * rxi;
        }
-       return g;
+       return (new add(g))->setflag(status_flags::dynallocated);
 }
 
 /** Exception thrown by heur_gcd() to signal failure. */
@@ -1331,17 +1355,17 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
        heur_gcd_called++;
 #endif
 
-       // Algorithms only works for non-vanishing input polynomials
+       // Algorithm only works for non-vanishing input polynomials
        if (a.is_zero() || b.is_zero())
-               return *new ex(fail());
+               return (new fail())->setflag(status_flags::dynallocated);
 
        // GCD of two numeric values -> CLN
        if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric)) {
-               numeric g = gcd(ex_to_numeric(a), ex_to_numeric(b));
+               numeric g = gcd(ex_to<numeric>(a), ex_to<numeric>(b));
                if (ca)
-                       *ca = ex_to_numeric(a) / g;
+                       *ca = ex_to<numeric>(a) / g;
                if (cb)
-                       *cb = ex_to_numeric(b) / g;
+                       *cb = ex_to<numeric>(b) / g;
                return g;
        }
 
@@ -1353,7 +1377,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
        numeric rgc = gc.inverse();
        ex p = a * rgc;
        ex q = b * rgc;
-       int maxdeg =  std::max(p.degree(x),q.degree(x));
+       int maxdeg =  std::max(p.degree(x), q.degree(x));
        
        // Find evaluation point
        numeric mp = p.max_coefficient();
@@ -1367,7 +1391,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
        // 6 tries maximum
        for (int t=0; t<6; t++) {
                if (xi.int_length() * maxdeg > 100000) {
-//std::clog << "giving up heur_gcd, xi.int_length = " << xi.int_length() << ", maxdeg = " << maxdeg << endl;
+//std::clog << "giving up heur_gcd, xi.int_length = " << xi.int_length() << ", maxdeg = " << maxdeg << std::endl;
                        throw gcdheu_failed();
                }
 
@@ -1377,7 +1401,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
                if (!is_ex_exactly_of_type(gamma, fail)) {
 
                        // Reconstruct polynomial from GCD of mapped polynomials
-                       ex g = interpolate(gamma, xi, x);
+                       ex g = interpolate(gamma, xi, x, maxdeg);
 
                        // Remove integer content
                        g /= g.integer_content();
@@ -1387,7 +1411,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
                        if (divide_in_z(p, g, ca ? *ca : dummy, var) && divide_in_z(q, g, cb ? *cb : dummy, var)) {
                                g *= gc;
                                ex lc = g.lcoeff(x);
-                               if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+                               if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
                                        return -g;
                                else
                                        return g;
@@ -1400,7 +1424,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
                                        if (ca)
                                                *ca = cp;
                                        ex lc = g.lcoeff(x);
-                                       if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+                                       if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
                                                return -g;
                                        else
                                                return g;
@@ -1413,7 +1437,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
                                        if (cb)
                                                *cb = cq;
                                        ex lc = g.lcoeff(x);
-                                       if (is_ex_exactly_of_type(lc, numeric) && ex_to_numeric(lc).is_negative())
+                                       if (is_ex_exactly_of_type(lc, numeric) && ex_to<numeric>(lc).is_negative())
                                                return -g;
                                        else
                                                return g;
@@ -1425,7 +1449,7 @@ static ex heur_gcd(const ex &a, const ex &b, ex *ca, ex *cb, sym_desc_vec::const
                // Next evaluation point
                xi = iquo(xi * isqrt(isqrt(xi)) * numeric(73794), numeric(27011));
        }
-       return *new ex(fail());
+       return (new fail())->setflag(status_flags::dynallocated);
 }
 
 
@@ -1446,7 +1470,7 @@ ex gcd(const ex &a, const ex &b, ex *ca, ex *cb, bool check_args)
 
        // GCD of numerics -> CLN
        if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric)) {
-               numeric g = gcd(ex_to_numeric(a), ex_to_numeric(b));
+               numeric g = gcd(ex_to<numeric>(a), ex_to<numeric>(b));
                if (ca || cb) {
                        if (g.is_zero()) {
                                if (ca)
@@ -1455,9 +1479,9 @@ ex gcd(const ex &a, const ex &b, ex *ca, ex *cb, bool check_args)
                                        *cb = _ex0();
                        } else {
                                if (ca)
-                                       *ca = ex_to_numeric(a) / g;
+                                       *ca = ex_to<numeric>(a) / g;
                                if (cb)
-                                       *cb = ex_to_numeric(b) / g;
+                                       *cb = ex_to<numeric>(b) / g;
                        }
                }
                return g;
@@ -1473,38 +1497,40 @@ ex gcd(const ex &a, const ex &b, ex *ca, ex *cb, bool check_args)
                if (is_ex_exactly_of_type(b, mul) && b.nops() > a.nops())
                        goto factored_b;
 factored_a:
-               ex g = _ex1();
-               ex acc_ca = _ex1();
+               unsigned num = a.nops();
+               exvector g; g.reserve(num);
+               exvector acc_ca; acc_ca.reserve(num);
                ex part_b = b;
-               for (unsigned i=0; i<a.nops(); i++) {
+               for (unsigned i=0; i<num; i++) {
                        ex part_ca, part_cb;
-                       g *= gcd(a.op(i), part_b, &part_ca, &part_cb, check_args);
-                       acc_ca *= part_ca;
+                       g.push_back(gcd(a.op(i), part_b, &part_ca, &part_cb, check_args));
+                       acc_ca.push_back(part_ca);
                        part_b = part_cb;
                }
                if (ca)
-                       *ca = acc_ca;
+                       *ca = (new mul(acc_ca))->setflag(status_flags::dynallocated);
                if (cb)
                        *cb = part_b;
-               return g;
+               return (new mul(g))->setflag(status_flags::dynallocated);
        } else if (is_ex_exactly_of_type(b, mul)) {
                if (is_ex_exactly_of_type(a, mul) && a.nops() > b.nops())
                        goto factored_a;
 factored_b:
-               ex g = _ex1();
-               ex acc_cb = _ex1();
+               unsigned num = b.nops();
+               exvector g; g.reserve(num);
+               exvector acc_cb; acc_cb.reserve(num);
                ex part_a = a;
-               for (unsigned i=0; i<b.nops(); i++) {
+               for (unsigned i=0; i<num; i++) {
                        ex part_ca, part_cb;
-                       g *= gcd(part_a, b.op(i), &part_ca, &part_cb, check_args);
-                       acc_cb *= part_cb;
+                       g.push_back(gcd(part_a, b.op(i), &part_ca, &part_cb, check_args));
+                       acc_cb.push_back(part_cb);
                        part_a = part_ca;
                }
                if (ca)
                        *ca = part_a;
                if (cb)
-                       *cb = acc_cb;
-               return g;
+                       *cb = (new mul(acc_cb))->setflag(status_flags::dynallocated);
+               return (new mul(g))->setflag(status_flags::dynallocated);
        }
 
 #if FAST_COMPARE
@@ -1599,20 +1625,20 @@ factored_b:
        int min_ldeg = std::min(ldeg_a,ldeg_b);
        if (min_ldeg > 0) {
                ex common = power(x, min_ldeg);
-//std::clog << "trivial common factor " << common << endl;
+//std::clog << "trivial common factor " << common << std::endl;
                return gcd((aex / common).expand(), (bex / common).expand(), ca, cb, false) * common;
        }
 
        // Try to eliminate variables
        if (var->deg_a == 0) {
-//std::clog << "eliminating variable " << x << " from b" << endl;
+//std::clog << "eliminating variable " << x << " from b" << std::endl;
                ex c = bex.content(x);
                ex g = gcd(aex, c, ca, cb, false);
                if (cb)
                        *cb *= bex.unit(x) * bex.primpart(x, c);
                return g;
        } else if (var->deg_b == 0) {
-//std::clog << "eliminating variable " << x << " from a" << endl;
+//std::clog << "eliminating variable " << x << " from a" << std::endl;
                ex c = aex.content(x);
                ex g = gcd(c, bex, ca, cb, false);
                if (ca)
@@ -1626,10 +1652,10 @@ factored_b:
        try {
                g = heur_gcd(aex, bex, ca, cb, var);
        } catch (gcdheu_failed) {
-               g = *new ex(fail());
+               g = fail();
        }
        if (is_ex_exactly_of_type(g, fail)) {
-//std::clog << "heuristics failed" << endl;
+//std::clog << "heuristics failed" << std::endl;
 #if STATISTICS
                heur_gcd_failed++;
 #endif
@@ -1677,7 +1703,7 @@ factored_b:
 ex lcm(const ex &a, const ex &b, bool check_args)
 {
        if (is_ex_exactly_of_type(a, numeric) && is_ex_exactly_of_type(b, numeric))
-               return lcm(ex_to_numeric(a), ex_to_numeric(b));
+               return lcm(ex_to<numeric>(a), ex_to<numeric>(b));
        if (check_args && (!a.info(info_flags::rational_polynomial) || !b.info(info_flags::rational_polynomial)))
                throw(std::invalid_argument("lcm: arguments must be polynomials over the rationals"));
        
@@ -1698,9 +1724,8 @@ ex lcm(const ex &a, const ex &b, bool check_args)
  *            polynomial in x.
  *  @param x  variable to factor in
  *  @return   vector of factors sorted in ascending degree */
-exvector sqrfree_yun(const ex &a, const symbol &x)
+static exvector sqrfree_yun(const ex &a, const symbol &x)
 {
-       int i = 0;
        exvector res;
        ex w = a;
        ex z = w.diff(x);
@@ -1716,10 +1741,10 @@ exvector sqrfree_yun(const ex &a, const symbol &x)
                z = y - w.diff(x);
                g = gcd(w, z);
                res.push_back(g);
-               ++i;
        } while (!z.is_zero());
        return res;
 }
+
 /** Compute square-free factorization of multivariate polynomial in Q[X].
  *
  *  @param a  multivariate polynomial over Q[X]
@@ -1730,6 +1755,7 @@ ex sqrfree(const ex &a, const lst &l)
        if (is_ex_of_type(a,numeric) ||     // algorithm does not trap a==0
            is_ex_of_type(a,symbol))        // shortcut
                return a;
+
        // If no lst of variables to factorize in was specified we have to
        // invent one now.  Maybe one can optimize here by reversing the order
        // or so, I don't know.
@@ -1737,34 +1763,46 @@ ex sqrfree(const ex &a, const lst &l)
        if (l.nops()==0) {
                sym_desc_vec sdv;
                get_symbol_stats(a, _ex0(), sdv);
-               for (sym_desc_vec::iterator it=sdv.begin(); it!=sdv.end(); ++it)
+               sym_desc_vec::const_iterator it = sdv.begin(), itend = sdv.end();
+               while (it != itend) {
                        args.append(*it->sym);
+                       ++it;
+               }
        } else {
                args = l;
        }
+
        // Find the symbol to factor in at this stage
        if (!is_ex_of_type(args.op(0), symbol))
                throw (std::runtime_error("sqrfree(): invalid factorization variable"));
-       const symbol x = ex_to_symbol(args.op(0));
+       const symbol x = ex_to<symbol>(args.op(0));
+
        // convert the argument from something in Q[X] to something in Z[X]
        numeric lcm = lcm_of_coefficients_denominators(a);
        ex tmp = multiply_lcm(a,lcm);
+
        // find the factors
        exvector factors = sqrfree_yun(tmp,x);
+
        // construct the next list of symbols with the first element popped
-       lst newargs;
-       for (int i=1; i<args.nops(); ++i)
-               newargs.append(args.op(i));
+       lst newargs = args;
+       newargs.remove_first();
+
        // recurse down the factors in remaining vars
        if (newargs.nops()>0) {
-               for (exvector::iterator i=factors.begin(); i!=factors.end(); ++i)
+               exvector::iterator i = factors.begin(), end = factors.end();
+               while (i != end) {
                        *i = sqrfree(*i, newargs);
+                       ++i;
+               }
        }
+
        // Done with recursion, now construct the final result
        ex result = _ex1();
-       exvector::iterator it = factors.begin();
-       for (int p = 1; it!=factors.end(); ++it, ++p)
+       exvector::const_iterator it = factors.begin(), itend = factors.end();
+       for (int p = 1; it!=itend; ++it, ++p)
                result *= power(*it, p);
+
        // Yun's algorithm does not account for constant factors.  (For
        // univariate polynomials it works only in the monic case.)  We can
        // correct this by inserting what has been lost back into the result:
@@ -1772,6 +1810,75 @@ ex sqrfree(const ex &a, const lst &l)
        return result * lcm.inverse();
 }
 
+/** Compute square-free partial fraction decomposition of rational function
+ *  a(x).
+ *
+ *  @param a rational function over Z[x], treated as univariate polynomial
+ *           in x
+ *  @param x variable to factor in
+ *  @return decomposed rational function */
+ex sqrfree_parfrac(const ex & a, const symbol & x)
+{
+       // Find numerator and denominator
+       ex nd = numer_denom(a);
+       ex numer = nd.op(0), denom = nd.op(1);
+//clog << "numer = " << numer << ", denom = " << denom << endl;
+
+       // Convert N(x)/D(x) -> Q(x) + R(x)/D(x), so degree(R) < degree(D)
+       ex red_poly = quo(numer, denom, x), red_numer = rem(numer, denom, x).expand();
+//clog << "red_poly = " << red_poly << ", red_numer = " << red_numer << endl;
+
+       // Factorize denominator and compute cofactors
+       exvector yun = sqrfree_yun(denom, x);
+//clog << "yun factors: " << exprseq(yun) << endl;
+       unsigned num_yun = yun.size();
+       exvector factor; factor.reserve(num_yun);
+       exvector cofac; cofac.reserve(num_yun);
+       for (unsigned i=0; i<num_yun; i++) {
+               if (!yun[i].is_equal(_ex1())) {
+                       for (unsigned j=0; j<=i; j++) {
+                               factor.push_back(pow(yun[i], j+1));
+                               ex prod = _ex1();
+                               for (unsigned k=0; k<num_yun; k++) {
+                                       if (k == i)
+                                               prod *= pow(yun[k], i-j);
+                                       else
+                                               prod *= pow(yun[k], k+1);
+                               }
+                               cofac.push_back(prod.expand());
+                       }
+               }
+       }
+       unsigned num_factors = factor.size();
+//clog << "factors  : " << exprseq(factor) << endl;
+//clog << "cofactors: " << exprseq(cofac) << endl;
+
+       // Construct coefficient matrix for decomposition
+       int max_denom_deg = denom.degree(x);
+       matrix sys(max_denom_deg + 1, num_factors);
+       matrix rhs(max_denom_deg + 1, 1);
+       for (int i=0; i<=max_denom_deg; i++) {
+               for (unsigned j=0; j<num_factors; j++)
+                       sys(i, j) = cofac[j].coeff(x, i);
+               rhs(i, 0) = red_numer.coeff(x, i);
+       }
+//clog << "coeffs: " << sys << endl;
+//clog << "rhs   : " << rhs << endl;
+
+       // Solve resulting linear system
+       matrix vars(num_factors, 1);
+       for (unsigned i=0; i<num_factors; i++)
+               vars(i, 0) = symbol();
+       matrix sol = sys.solve(vars, rhs);
+
+       // Sum up decomposed fractions
+       ex sum = 0;
+       for (unsigned i=0; i<num_factors; i++)
+               sum += sol(i, 0) / factor[i];
+
+       return red_poly + sum;
+}
+
 
 /*
  *  Normal form of rational functions
@@ -1785,6 +1892,7 @@ ex sqrfree(const ex &a, const lst &l)
  *  the information that (a+b) is the numerator and 3 is the denominator.
  */
 
+
 /** Create a symbol for replacing the expression "e" (or return a previously
  *  assigned symbol). The symbol is appended to sym_lst and returned, the
  *  expression is appended to repl_lst.
@@ -1828,12 +1936,31 @@ static ex replace_with_symbol(const ex &e, lst &repl_lst)
        return es;
 }
 
-/** Default implementation of ex::normal(). It replaces the object with a
- *  temporary symbol.
+
+/** Function object to be applied by basic::normal(). */
+struct normal_map_function : public map_function {
+       int level;
+       normal_map_function(int l) : level(l) {}
+       ex operator()(const ex & e) { return normal(e, level); }
+};
+
+/** Default implementation of ex::normal(). It normalizes the children and
+ *  replaces the object with a temporary symbol.
  *  @see ex::normal */
 ex basic::normal(lst &sym_lst, lst &repl_lst, int level) const
 {
-       return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+       if (nops() == 0)
+               return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+       else {
+               if (level == 1)
+                       return (new lst(replace_with_symbol(*this, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+               else if (level == -max_recursion_level)
+                       throw(std::runtime_error("max recursion level reached"));
+               else {
+                       normal_map_function map_normal(level - 1);
+                       return (new lst(replace_with_symbol(map(map_normal), sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
+               }
+       }
 }
 
 
@@ -1879,7 +2006,7 @@ static ex frac_cancel(const ex &n, const ex &d)
        ex den = d;
        numeric pre_factor = _num1();
 
-//std::clog << "frac_cancel num = " << num << ", den = " << den << endl;
+//std::clog << "frac_cancel num = " << num << ", den = " << den << std::endl;
 
        // Handle trivial case where denominator is 1
        if (den.is_equal(_ex1()))
@@ -1911,14 +2038,14 @@ static ex frac_cancel(const ex &n, const ex &d)
        const symbol *x;
        if (get_first_symbol(den, x)) {
                GINAC_ASSERT(is_ex_exactly_of_type(den.unit(*x),numeric));
-               if (ex_to_numeric(den.unit(*x)).is_negative()) {
+               if (ex_to<numeric>(den.unit(*x)).is_negative()) {
                        num *= _ex_1();
                        den *= _ex_1();
                }
        }
 
        // Return result as list
-//std::clog << " returns num = " << num << ", den = " << den << ", pre_factor = " << pre_factor << endl;
+//std::clog << " returns num = " << num << ", den = " << den << ", pre_factor = " << pre_factor << std::endl;
        return (new lst(num * pre_factor.numer(), den * pre_factor.denom()))->setflag(status_flags::dynallocated);
 }
 
@@ -1956,10 +2083,10 @@ ex add::normal(lst &sym_lst, lst &repl_lst, int level) const
        // Add fractions sequentially
        exvector::const_iterator num_it = nums.begin(), num_itend = nums.end();
        exvector::const_iterator den_it = dens.begin(), den_itend = dens.end();
-//std::clog << " num = " << *num_it << ", den = " << *den_it << endl;
+//std::clog << " num = " << *num_it << ", den = " << *den_it << std::endl;
        ex num = *num_it++, den = *den_it++;
        while (num_it != num_itend) {
-//std::clog << " num = " << *num_it << ", den = " << *den_it << endl;
+//std::clog << " num = " << *num_it << ", den = " << *den_it << std::endl;
                ex next_num = *num_it++, next_den = *den_it++;
 
                // Trivially add sequences of fractions with identical denominators
@@ -1975,7 +2102,7 @@ ex add::normal(lst &sym_lst, lst &repl_lst, int level) const
                num = ((num * co_den2) + (next_num * co_den1)).expand();
                den *= co_den2;         // this is the lcm(den, next_den)
        }
-//std::clog << " common denominator = " << den << endl;
+//std::clog << " common denominator = " << den << std::endl;
 
        // Cancel common factors from num/den
        return frac_cancel(num, den);
@@ -1993,22 +2120,23 @@ ex mul::normal(lst &sym_lst, lst &repl_lst, int level) const
                throw(std::runtime_error("max recursion level reached"));
 
        // Normalize children, separate into numerator and denominator
-       ex num = _ex1();
-       ex den = _ex1(); 
+       exvector num; num.reserve(seq.size());
+       exvector den; den.reserve(seq.size());
        ex n;
        epvector::const_iterator it = seq.begin(), itend = seq.end();
        while (it != itend) {
                n = recombine_pair_to_ex(*it).bp->normal(sym_lst, repl_lst, level-1);
-               num *= n.op(0);
-               den *= n.op(1);
+               num.push_back(n.op(0));
+               den.push_back(n.op(1));
                it++;
        }
        n = overall_coeff.bp->normal(sym_lst, repl_lst, level-1);
-       num *= n.op(0);
-       den *= n.op(1);
+       num.push_back(n.op(0));
+       den.push_back(n.op(1));
 
        // Perform fraction cancellation
-       return frac_cancel(num, den);
+       return frac_cancel((new mul(num))->setflag(status_flags::dynallocated),
+                          (new mul(den))->setflag(status_flags::dynallocated));
 }
 
 
@@ -2076,24 +2204,18 @@ ex power::normal(lst &sym_lst, lst &repl_lst, int level) const
 ex pseries::normal(lst &sym_lst, lst &repl_lst, int level) 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.normal();
                if (!restexp.is_zero())
                        newseq.push_back(expair(restexp, i->coeff));
+               ++i;
        }
        ex n = pseries(relational(var,point), newseq);
        return (new lst(replace_with_symbol(n, sym_lst, repl_lst), _ex1()))->setflag(status_flags::dynallocated);
 }
 
 
-/** Implementation of ex::normal() for relationals. It normalizes both sides.
- *  @see ex::normal */
-ex relational::normal(lst &sym_lst, lst &repl_lst, int level) const
-{
-       return (new lst(relational(lh.normal(), rh.normal(), o), _ex1()))->setflag(status_flags::dynallocated);
-}
-
-
 /** Normalization of rational functions.
  *  This function converts an expression to its normal form
  *  "numerator/denominator", where numerator and denominator are (relatively
@@ -2121,9 +2243,9 @@ ex ex::normal(int level) const
        return e.op(0) / e.op(1);
 }
 
-/** Numerator of an expression. If the expression is not of the normal form
- *  "numerator/denominator", it is first converted to this form and then the
- *  numerator is returned.
+/** Get numerator of an expression. If the expression is not of the normal
+ *  form "numerator/denominator", it is first converted to this form and
+ *  then the numerator is returned.
  *
  *  @see ex::normal
  *  @return numerator */
@@ -2141,9 +2263,9 @@ ex ex::numer(void) const
                return e.op(0);
 }
 
-/** Denominator of an expression. If the expression is not of the normal form
- *  "numerator/denominator", it is first converted to this form and then the
- *  denominator is returned.
+/** Get denominator of an expression. If the expression is not of the normal
+ *  form "numerator/denominator", it is first converted to this form and
+ *  then the denominator is returned.
  *
  *  @see ex::normal
  *  @return denominator */
@@ -2161,6 +2283,26 @@ ex ex::denom(void) const
                return e.op(1);
 }
 
+/** Get numerator and denominator of an expression. If the expresison is not
+ *  of the normal form "numerator/denominator", it is first converted to this
+ *  form and then a list [numerator, denominator] is returned.
+ *
+ *  @see ex::normal
+ *  @return a list [numerator, denominator] */
+ex ex::numer_denom(void) const
+{
+       lst sym_lst, repl_lst;
+
+       ex e = bp->normal(sym_lst, repl_lst, 0);
+       GINAC_ASSERT(is_ex_of_type(e, lst));
+
+       // Re-insert replaced symbols
+       if (sym_lst.nops() > 0)
+               return e.subs(sym_lst, repl_lst);
+       else
+               return e;
+}
+
 
 /** Default implementation of ex::to_rational(). It replaces the object with a
  *  temporary symbol.
@@ -2218,14 +2360,16 @@ ex expairseq::to_rational(lst &repl_lst) const
 {
        epvector s;
        s.reserve(seq.size());
-       for (epvector::const_iterator it=seq.begin(); it!=seq.end(); ++it) {
-               s.push_back(split_ex_to_pair(recombine_pair_to_ex(*it).to_rational(repl_lst)));
-               // s.push_back(combine_ex_with_coeff_to_pair((*it).rest.to_rational(repl_lst),
+       epvector::const_iterator i = seq.begin(), end = seq.end();
+       while (i != end) {
+               s.push_back(split_ex_to_pair(recombine_pair_to_ex(*i).to_rational(repl_lst)));
+               ++i;
        }
        ex oc = overall_coeff.to_rational(repl_lst);
        if (oc.info(info_flags::numeric))
                return thisexpairseq(s, overall_coeff);
-       else s.push_back(combine_ex_with_coeff_to_pair(oc,_ex1()));
+       else
+               s.push_back(combine_ex_with_coeff_to_pair(oc, _ex1()));
        return thisexpairseq(s, default_overall_coeff());
 }