X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fpseries.cpp;h=c290fe0a1f7b09b0c73fa2cebdf4e9cb1f609c38;hp=7fbf73113a74f293c3cca3b151083ff29dfa2bb9;hb=079c558d4f9758cd2777a2808a02d64cb1f70c8e;hpb=97af29c12bb3074cfb4e674d71000f0712c51ba2 diff --git a/ginac/pseries.cpp b/ginac/pseries.cpp index 7fbf7311..c290fe0a 100644 --- a/ginac/pseries.cpp +++ b/ginac/pseries.cpp @@ -4,7 +4,7 @@ * methods for series expansion. */ /* - * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany + * GiNaC Copyright (C) 1999-2010 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 @@ -18,94 +18,62 @@ * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ -#include - #include "pseries.h" #include "add.h" -#include "inifcns.h" +#include "inifcns.h" // for Order function #include "lst.h" #include "mul.h" #include "power.h" #include "relational.h" +#include "operators.h" #include "symbol.h" +#include "integral.h" #include "archive.h" #include "utils.h" -#include "debugmsg.h" -#ifndef NO_NAMESPACE_GINAC +#include +#include +#include + namespace GiNaC { -#endif // ndef NO_NAMESPACE_GINAC -GINAC_IMPLEMENT_REGISTERED_CLASS(pseries, basic) +GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(pseries, basic, + print_func(&pseries::do_print). + print_func(&pseries::do_print_latex). + print_func(&pseries::do_print_tree). + print_func(&pseries::do_print_python). + print_func(&pseries::do_print_python_repr)) + /* - * Default constructor, destructor, copy constructor, assignment operator and helpers + * Default constructor */ -pseries::pseries() : basic(TINFO_pseries) -{ - debugmsg("pseries default constructor", LOGLEVEL_CONSTRUCT); -} - -pseries::~pseries() -{ - debugmsg("pseries destructor", LOGLEVEL_DESTRUCT); - destroy(false); -} - -pseries::pseries(const pseries &other) -{ - debugmsg("pseries copy constructor", LOGLEVEL_CONSTRUCT); - copy(other); -} - -const pseries &pseries::operator=(const pseries & other) -{ - debugmsg("pseries operator=", LOGLEVEL_ASSIGNMENT); - if (this != &other) { - destroy(true); - copy(other); - } - return *this; -} - -void pseries::copy(const pseries &other) -{ - inherited::copy(other); - seq = other.seq; - var = other.var; - point = other.point; -} - -void pseries::destroy(bool call_parent) -{ - if (call_parent) - inherited::destroy(call_parent); -} +pseries::pseries() { } /* - * Other constructors + * Other ctors */ /** Construct pseries from a vector of coefficients and powers. * expair.rest holds the coefficient, expair.coeff holds the power. * The powers must be integers (positive or negative) and in ascending order; - * the last coefficient can be Order(_ex1()) to represent a truncated, + * the last coefficient can be Order(_ex1) to represent a truncated, * non-terminating series. * - * @param var_ series variable (must hold a symbol) - * @param point_ expansion point + * @param rel_ expansion variable and point (must hold a relational) * @param ops_ vector of {coefficient, power} pairs (coefficient must not be zero) * @return newly constructed pseries */ -pseries::pseries(const ex &var_, const ex &point_, const epvector &ops_) - : basic(TINFO_pseries), seq(ops_), var(var_), point(point_) +pseries::pseries(const ex &rel_, const epvector &ops_) : seq(ops_) { - debugmsg("pseries constructor from ex,ex,epvector", LOGLEVEL_CONSTRUCT); - GINAC_ASSERT(is_ex_exactly_of_type(var_, symbol)); + GINAC_ASSERT(is_a(rel_)); + GINAC_ASSERT(is_a(rel_.lhs())); + point = rel_.rhs(); + var = rel_.lhs(); } @@ -113,293 +81,620 @@ pseries::pseries(const ex &var_, const ex &point_, const epvector &ops_) * Archiving */ -/** Construct object from archive_node. */ -pseries::pseries(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst) +void pseries::read_archive(const archive_node &n, lst &sym_lst) { - debugmsg("pseries constructor from archive_node", LOGLEVEL_CONSTRUCT); - for (unsigned int i=0; true; i++) { - ex rest; - ex coeff; - if (n.find_ex("coeff", rest, sym_lst, i) && n.find_ex("power", coeff, sym_lst, i)) - seq.push_back(expair(rest, coeff)); - else - break; - } - n.find_ex("var", var, sym_lst); - n.find_ex("point", point, sym_lst); + inherited::read_archive(n, sym_lst); + archive_node::archive_node_cit first = n.find_first("coeff"); + archive_node::archive_node_cit last = n.find_last("power"); + ++last; + seq.reserve((last-first)/2); + + for (archive_node::archive_node_cit loc = first; loc < last;) { + ex rest; + ex coeff; + n.find_ex_by_loc(loc++, rest, sym_lst); + n.find_ex_by_loc(loc++, coeff, sym_lst); + seq.push_back(expair(rest, coeff)); + } + + n.find_ex("var", var, sym_lst); + n.find_ex("point", point, sym_lst); } -/** Unarchive the object. */ -ex pseries::unarchive(const archive_node &n, const lst &sym_lst) +void pseries::archive(archive_node &n) const { - return (new pseries(n, sym_lst))->setflag(status_flags::dynallocated); + inherited::archive(n); + epvector::const_iterator i = seq.begin(), iend = seq.end(); + while (i != iend) { + n.add_ex("coeff", i->rest); + n.add_ex("power", i->coeff); + ++i; + } + n.add_ex("var", var); + n.add_ex("point", point); } -/** Archive the object. */ -void pseries::archive(archive_node &n) const + +////////// +// functions overriding virtual functions from base classes +////////// + +void pseries::print_series(const print_context & c, const char *openbrace, const char *closebrace, const char *mul_sym, const char *pow_sym, unsigned level) const { - inherited::archive(n); - epvector::const_iterator i = seq.begin(), iend = seq.end(); - while (i != iend) { - n.add_ex("coeff", i->rest); - n.add_ex("power", i->coeff); - i++; - } - n.add_ex("var", var); - n.add_ex("point", point); + if (precedence() <= level) + c.s << '('; + + // objects of type pseries must not have any zero entries, so the + // trivial (zero) pseries needs a special treatment here: + if (seq.empty()) + c.s << '0'; + + epvector::const_iterator i = seq.begin(), end = seq.end(); + while (i != end) { + + // print a sign, if needed + if (i != seq.begin()) + c.s << '+'; + + if (!is_order_function(i->rest)) { + + // print 'rest', i.e. the expansion coefficient + if (i->rest.info(info_flags::numeric) && + i->rest.info(info_flags::positive)) { + i->rest.print(c); + } else { + c.s << openbrace << '('; + i->rest.print(c); + c.s << ')' << closebrace; + } + + // print 'coeff', something like (x-1)^42 + if (!i->coeff.is_zero()) { + c.s << mul_sym; + if (!point.is_zero()) { + c.s << openbrace << '('; + (var-point).print(c); + c.s << ')' << closebrace; + } else + var.print(c); + if (i->coeff.compare(_ex1)) { + c.s << pow_sym; + c.s << openbrace; + if (i->coeff.info(info_flags::negative)) { + c.s << '('; + i->coeff.print(c); + c.s << ')'; + } else + i->coeff.print(c); + c.s << closebrace; + } + } + } else + Order(power(var-point,i->coeff)).print(c); + ++i; + } + + if (precedence() <= level) + c.s << ')'; } +void pseries::do_print(const print_context & c, unsigned level) const +{ + print_series(c, "", "", "*", "^", level); +} -/* - * Functions overriding virtual functions from base classes - */ +void pseries::do_print_latex(const print_latex & c, unsigned level) const +{ + print_series(c, "{", "}", " ", "^", level); +} -basic *pseries::duplicate() const +void pseries::do_print_python(const print_python & c, unsigned level) const { - debugmsg("pseries duplicate", LOGLEVEL_DUPLICATE); - return new pseries(*this); + print_series(c, "", "", "*", "**", level); } -void pseries::print(ostream &os, unsigned upper_precedence) const +void pseries::do_print_tree(const print_tree & c, unsigned level) const { - debugmsg("pseries print", LOGLEVEL_PRINT); - convert_to_poly().print(os, upper_precedence); + c.s << std::string(level, ' ') << class_name() << " @" << this + << std::hex << ", hash=0x" << hashvalue << ", flags=0x" << flags << std::dec + << std::endl; + size_t num = seq.size(); + for (size_t i=0; i(other)); + const pseries &o = static_cast(other); + + // first compare the lengths of the series... + if (seq.size()>o.seq.size()) + return 1; + if (seq.size()compare(*o_it); + if (cmpval) + return cmpval; + ++it; + ++o_it; } - os << ")"; + + // so they are equal. + return 0; } -unsigned pseries::nops(void) const +/** Return the number of operands including a possible order term. */ +size_t pseries::nops() const { - return seq.size(); + return seq.size(); } -ex pseries::op(int i) const +/** Return the ith term in the series when represented as a sum. */ +ex pseries::op(size_t i) const { - if (i < 0 || unsigned(i) >= seq.size()) - throw (std::out_of_range("op() out of range")); - return seq[i].rest * power(var - point, seq[i].coeff); + if (i >= seq.size()) + throw (std::out_of_range("op() out of range")); + + if (is_order_function(seq[i].rest)) + return Order(power(var-point, seq[i].coeff)); + return seq[i].rest * power(var - point, seq[i].coeff); } -ex &pseries::let_op(int i) +/** Return degree of highest power of the series. This is usually the exponent + * of the Order term. If s is not the expansion variable of the series, the + * series is examined termwise. */ +int pseries::degree(const ex &s) const { - throw (std::logic_error("let_op not defined for pseries")); + if (var.is_equal(s)) { + // Return last exponent + if (seq.size()) + return ex_to((seq.end()-1)->coeff).to_int(); + else + return 0; + } else { + epvector::const_iterator it = seq.begin(), itend = seq.end(); + if (it == itend) + return 0; + int max_pow = std::numeric_limits::min(); + while (it != itend) { + int pow = it->rest.degree(s); + if (pow > max_pow) + max_pow = pow; + ++it; + } + return max_pow; + } } -int pseries::degree(const symbol &s) const +/** Return degree of lowest power of the series. This is usually the exponent + * of the leading term. If s is not the expansion variable of the series, the + * series is examined termwise. If s is the expansion variable but the + * expansion point is not zero the series is not expanded to find the degree. + * I.e.: (1-x) + (1-x)^2 + Order((1-x)^3) has ldegree(x) 1, not 0. */ +int pseries::ldegree(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(); - else - return 0; - } else { - epvector::const_iterator it = seq.begin(), itend = seq.end(); - if (it == itend) - return 0; - int max_pow = INT_MIN; - while (it != itend) { - int pow = it->rest.degree(s); - if (pow > max_pow) - max_pow = pow; - it++; - } - return max_pow; - } + if (var.is_equal(s)) { + // Return first exponent + if (seq.size()) + return ex_to((seq.begin())->coeff).to_int(); + else + return 0; + } else { + epvector::const_iterator it = seq.begin(), itend = seq.end(); + if (it == itend) + return 0; + int min_pow = std::numeric_limits::max(); + while (it != itend) { + int pow = it->rest.ldegree(s); + if (pow < min_pow) + min_pow = pow; + ++it; + } + return min_pow; + } } -int pseries::ldegree(const symbol &s) const +/** Return coefficient of degree n in power series if s is the expansion + * variable. If the expansion point is nonzero, by definition the n=1 + * coefficient in s of a+b*(s-z)+c*(s-z)^2+Order((s-z)^3) is b (assuming + * the expansion took place in the s in the first place). + * If s is not the expansion variable, an attempt is made to convert the + * series to a polynomial and return the corresponding coefficient from + * there. */ +ex pseries::coeff(const ex &s, int n) const { - if (var.is_equal(s)) { - // Return first exponent - if (seq.size()) - return ex_to_numeric((*(seq.begin())).coeff).to_int(); - else - return 0; - } else { - epvector::const_iterator it = seq.begin(), itend = seq.end(); - if (it == itend) - return 0; - int min_pow = INT_MAX; - while (it != itend) { - int pow = it->rest.ldegree(s); - if (pow < min_pow) - min_pow = pow; - it++; - } - return min_pow; - } + if (var.is_equal(s)) { + if (seq.empty()) + return _ex0; + + // Binary search in sequence for given power + numeric looking_for = numeric(n); + int lo = 0, hi = seq.size() - 1; + while (lo <= hi) { + int mid = (lo + hi) / 2; + GINAC_ASSERT(is_exactly_a(seq[mid].coeff)); + int cmp = ex_to(seq[mid].coeff).compare(looking_for); + switch (cmp) { + case -1: + lo = mid + 1; + break; + case 0: + return seq[mid].rest; + case 1: + hi = mid - 1; + break; + default: + throw(std::logic_error("pseries::coeff: compare() didn't return -1, 0 or 1")); + } + } + return _ex0; + } else + return convert_to_poly().coeff(s, n); } -ex pseries::coeff(const symbol &s, int n) const +/** Does nothing. */ +ex pseries::collect(const ex &s, bool distributed) const { - if (var.is_equal(s)) { - epvector::const_iterator it = seq.begin(), itend = seq.end(); - while (it != itend) { - int pow = ex_to_numeric(it->coeff).to_int(); - if (pow == n) - return it->rest; - if (pow > n) - return _ex0(); - it++; - } - return _ex0(); - } else - return convert_to_poly().coeff(s, n); + return *this; } +/** Perform coefficient-wise automatic term rewriting rules in this class. */ ex pseries::eval(int level) const { - if (level == 1) - return this->hold(); - - // Construct a new series with evaluated coefficients - epvector new_seq; - new_seq.reserve(seq.size()); - epvector::const_iterator it = seq.begin(), itend = seq.end(); - while (it != itend) { - new_seq.push_back(expair(it->rest.eval(level-1), it->coeff)); - it++; - } - return (new pseries(var, point, new_seq))->setflag(status_flags::dynallocated | status_flags::evaluated); -} - -/** Evaluate numerically. The order term is dropped. */ + if (level == 1) + return this->hold(); + + if (level == -max_recursion_level) + throw (std::runtime_error("pseries::eval(): recursion limit exceeded")); + + // Construct a new series with evaluated coefficients + epvector new_seq; + new_seq.reserve(seq.size()); + epvector::const_iterator it = seq.begin(), itend = seq.end(); + while (it != itend) { + new_seq.push_back(expair(it->rest.eval(level-1), it->coeff)); + ++it; + } + return (new pseries(relational(var,point), new_seq))->setflag(status_flags::dynallocated | status_flags::evaluated); +} + +/** Evaluate coefficients numerically. */ ex pseries::evalf(int level) const { - return convert_to_poly().evalf(level); + if (level == 1) + return *this; + + if (level == -max_recursion_level) + throw (std::runtime_error("pseries::evalf(): recursion limit exceeded")); + + // Construct a new series with evaluated coefficients + epvector new_seq; + new_seq.reserve(seq.size()); + epvector::const_iterator it = seq.begin(), itend = seq.end(); + while (it != itend) { + new_seq.push_back(expair(it->rest.evalf(level-1), it->coeff)); + ++it; + } + return (new pseries(relational(var,point), new_seq))->setflag(status_flags::dynallocated | status_flags::evaluated); +} + +ex pseries::conjugate() const +{ + if(!var.info(info_flags::real)) + return conjugate_function(*this).hold(); + + epvector * newseq = conjugateepvector(seq); + ex newpoint = point.conjugate(); + + if (!newseq && are_ex_trivially_equal(point, newpoint)) { + return *this; + } + + ex result = (new pseries(var==newpoint, newseq ? *newseq : seq))->setflag(status_flags::dynallocated); + if (newseq) { + delete newseq; + } + return result; +} + +ex pseries::real_part() const +{ + if(!var.info(info_flags::real)) + return real_part_function(*this).hold(); + ex newpoint = point.real_part(); + if(newpoint != point) + return real_part_function(*this).hold(); + + epvector v; + v.reserve(seq.size()); + for(epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) + v.push_back(expair((i->rest).real_part(), i->coeff)); + return (new pseries(var==point, v))->setflag(status_flags::dynallocated); +} + +ex pseries::imag_part() const +{ + if(!var.info(info_flags::real)) + return imag_part_function(*this).hold(); + ex newpoint = point.real_part(); + if(newpoint != point) + return imag_part_function(*this).hold(); + + epvector v; + v.reserve(seq.size()); + for(epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) + v.push_back(expair((i->rest).imag_part(), i->coeff)); + return (new pseries(var==point, v))->setflag(status_flags::dynallocated); +} + +ex pseries::eval_integ() const +{ + epvector *newseq = NULL; + for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) { + if (newseq) { + newseq->push_back(expair(i->rest.eval_integ(), i->coeff)); + continue; + } + ex newterm = i->rest.eval_integ(); + if (!are_ex_trivially_equal(newterm, i->rest)) { + newseq = new epvector; + newseq->reserve(seq.size()); + for (epvector::const_iterator j=seq.begin(); j!=i; ++j) + newseq->push_back(*j); + newseq->push_back(expair(newterm, i->coeff)); + } + } + + ex newpoint = point.eval_integ(); + if (newseq || !are_ex_trivially_equal(newpoint, point)) + return (new pseries(var==newpoint, *newseq)) + ->setflag(status_flags::dynallocated); + return *this; +} + +ex pseries::evalm() const +{ + // evalm each coefficient + epvector newseq; + bool something_changed = false; + for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) { + if (something_changed) { + ex newcoeff = i->rest.evalm(); + if (!newcoeff.is_zero()) + newseq.push_back(expair(newcoeff, i->coeff)); + } + else { + ex newcoeff = i->rest.evalm(); + if (!are_ex_trivially_equal(newcoeff, i->rest)) { + something_changed = true; + newseq.reserve(seq.size()); + std::copy(seq.begin(), i, std::back_inserter(newseq)); + if (!newcoeff.is_zero()) + newseq.push_back(expair(newcoeff, i->coeff)); + } + } + } + if (something_changed) + return (new pseries(var==point, newseq))->setflag(status_flags::dynallocated); + else + return *this; } -ex pseries::subs(const lst & ls, const lst & lr) const +ex pseries::subs(const exmap & m, unsigned options) const { // If expansion variable is being substituted, convert the series to a // polynomial and do the substitution there because the result might // no longer be a power series - if (ls.has(var)) - return convert_to_poly(true).subs(ls, lr); - + if (m.find(var) != m.end()) + return convert_to_poly(true).subs(m, options); + // Otherwise construct a new series with substituted coefficients and // expansion point - epvector new_seq; - new_seq.reserve(seq.size()); + epvector newseq; + newseq.reserve(seq.size()); epvector::const_iterator it = seq.begin(), itend = seq.end(); while (it != itend) { - new_seq.push_back(expair(it->rest.subs(ls, lr), it->coeff)); - it++; + newseq.push_back(expair(it->rest.subs(m, options), it->coeff)); + ++it; + } + return (new pseries(relational(var,point.subs(m, options)), newseq))->setflag(status_flags::dynallocated); +} + +/** Implementation of ex::expand() for a power series. It expands all the + * terms individually and returns the resulting series as a new pseries. */ +ex pseries::expand(unsigned options) const +{ + epvector newseq; + 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(var, point.subs(ls, lr), new_seq))->setflag(status_flags::dynallocated); + return (new pseries(relational(var,point), newseq)) + ->setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0)); } -/** Implementation of ex::diff() for a power series. It treats the series as a - * polynomial. +/** Implementation of ex::diff() for a power series. * @see ex::diff */ ex pseries::derivative(const symbol & s) const { - if (s == var) { - epvector new_seq; - epvector::const_iterator it = seq.begin(), itend = seq.end(); - - // FIXME: coeff might depend on var - while (it != itend) { - if (is_order_function(it->rest)) { - new_seq.push_back(expair(it->rest, it->coeff - 1)); - } else { - ex c = it->rest * it->coeff; - if (!c.is_zero()) - new_seq.push_back(expair(c, it->coeff - 1)); - } - it++; - } - return pseries(var, point, new_seq); - } else { - return *this; - } -} + epvector new_seq; + epvector::const_iterator it = seq.begin(), itend = seq.end(); + if (s == var) { + + // FIXME: coeff might depend on var + while (it != itend) { + if (is_order_function(it->rest)) { + new_seq.push_back(expair(it->rest, it->coeff - 1)); + } else { + ex c = it->rest * it->coeff; + if (!c.is_zero()) + new_seq.push_back(expair(c, it->coeff - 1)); + } + ++it; + } + + } else { + + while (it != itend) { + if (is_order_function(it->rest)) { + new_seq.push_back(*it); + } else { + ex c = it->rest.diff(s); + if (!c.is_zero()) + new_seq.push_back(expair(c, it->coeff)); + } + ++it; + } + } -/* - * Construct ordinary polynomial out of series - */ + return pseries(relational(var,point), new_seq); +} -/** Convert a pseries object to an ordinary polynomial. - * - * @param no_order flag: discard higher order terms */ ex pseries::convert_to_poly(bool no_order) const { - ex e; - epvector::const_iterator it = seq.begin(), itend = seq.end(); - - while (it != itend) { - if (is_order_function(it->rest)) { - if (!no_order) - e += Order(power(var - point, it->coeff)); - } else - e += it->rest * power(var - point, it->coeff); - it++; - } - return e; + ex e; + epvector::const_iterator it = seq.begin(), itend = seq.end(); + + while (it != itend) { + if (is_order_function(it->rest)) { + if (!no_order) + e += Order(power(var - point, it->coeff)); + } else + e += it->rest * power(var - point, it->coeff); + ++it; + } + return e; +} + +bool pseries::is_terminating() const +{ + return seq.empty() || !is_order_function((seq.end()-1)->rest); +} + +ex pseries::coeffop(size_t i) const +{ + if (i >=nops()) + throw (std::out_of_range("coeffop() out of range")); + return seq[i].rest; +} + +ex pseries::exponop(size_t i) const +{ + if (i >= nops()) + throw (std::out_of_range("exponop() out of range")); + return seq[i].coeff; } /* - * Implementation of series expansion + * Implementations of series expansion */ /** Default implementation of ex::series(). This performs Taylor expansion. * @see ex::series */ -ex basic::series(const symbol & s, const ex & point, int order) const -{ - epvector seq; - numeric fac(1); - ex deriv = *this; - ex coeff = deriv.subs(s == point); - if (!coeff.is_zero()) - seq.push_back(expair(coeff, numeric(0))); - - int n; - for (n=1; n(r.lhs()); + + // default for order-values that make no sense for Taylor expansion + if ((order <= 0) && this->has(s)) { + seq.push_back(expair(Order(_ex1), order)); + return pseries(r, seq); + } + + // do Taylor expansion + numeric fac = 1; + ex deriv = *this; + ex coeff = deriv.subs(r, subs_options::no_pattern); + + if (!coeff.is_zero()) { + seq.push_back(expair(coeff, _ex0)); + } + + int n; + for (n=1; n(r.lhs())); + + if (this->is_equal_same_type(ex_to(r.lhs()))) { if (order > 0 && !point.is_zero()) - seq.push_back(expair(point, _ex0())); + seq.push_back(expair(point, _ex0)); if (order > 1) - seq.push_back(expair(_ex1(), _ex1())); + seq.push_back(expair(_ex1, _ex1)); else - seq.push_back(expair(Order(_ex1()), numeric(order))); + seq.push_back(expair(Order(_ex1), numeric(order))); } else - seq.push_back(expair(*this, _ex0())); - return pseries(s, point, seq); + seq.push_back(expair(*this, _ex0)); + return pseries(r, seq); } @@ -410,99 +705,99 @@ ex symbol::series(const symbol & s, const ex & point, int order) const * @return the sum as a pseries */ ex pseries::add_series(const pseries &other) const { - // Adding two series with different variables or expansion points - // results in an empty (constant) series - if (!is_compatible_to(other)) { - epvector nul; - nul.push_back(expair(Order(_ex1()), _ex0())); - return pseries(var, point, nul); - } - - // Series addition - epvector new_seq; - epvector::const_iterator a = seq.begin(); - epvector::const_iterator b = other.seq.begin(); - epvector::const_iterator a_end = seq.end(); - epvector::const_iterator b_end = other.seq.end(); - int pow_a = INT_MAX, pow_b = INT_MAX; - for (;;) { - // If a is empty, fill up with elements from b and stop - if (a == a_end) { - while (b != b_end) { - new_seq.push_back(*b); - b++; - } - break; - } else - pow_a = ex_to_numeric((*a).coeff).to_int(); - - // If b is empty, fill up with elements from a and stop - if (b == b_end) { - while (a != a_end) { - new_seq.push_back(*a); - a++; - } - break; - } else - pow_b = ex_to_numeric((*b).coeff).to_int(); - - // a and b are non-empty, compare powers - if (pow_a < pow_b) { - // a has lesser power, get coefficient from a - new_seq.push_back(*a); - if (is_order_function((*a).rest)) - break; - a++; - } else if (pow_b < pow_a) { - // b has lesser power, get coefficient from b - new_seq.push_back(*b); - if (is_order_function((*b).rest)) - break; - b++; - } else { - // Add coefficient of a and b - if (is_order_function((*a).rest) || is_order_function((*b).rest)) { - new_seq.push_back(expair(Order(_ex1()), (*a).coeff)); - break; // Order term ends the sequence - } else { - ex sum = (*a).rest + (*b).rest; - if (!(sum.is_zero())) - new_seq.push_back(expair(sum, numeric(pow_a))); - a++; - b++; - } - } - } - return pseries(var, point, new_seq); + // Adding two series with different variables or expansion points + // results in an empty (constant) series + if (!is_compatible_to(other)) { + epvector nul; + nul.push_back(expair(Order(_ex1), _ex0)); + return pseries(relational(var,point), nul); + } + + // Series addition + epvector new_seq; + epvector::const_iterator a = seq.begin(); + epvector::const_iterator b = other.seq.begin(); + epvector::const_iterator a_end = seq.end(); + epvector::const_iterator b_end = other.seq.end(); + int pow_a = std::numeric_limits::max(), pow_b = std::numeric_limits::max(); + for (;;) { + // If a is empty, fill up with elements from b and stop + if (a == a_end) { + while (b != b_end) { + new_seq.push_back(*b); + ++b; + } + break; + } else + pow_a = ex_to((*a).coeff).to_int(); + + // If b is empty, fill up with elements from a and stop + if (b == b_end) { + while (a != a_end) { + new_seq.push_back(*a); + ++a; + } + break; + } else + pow_b = ex_to((*b).coeff).to_int(); + + // a and b are non-empty, compare powers + if (pow_a < pow_b) { + // a has lesser power, get coefficient from a + new_seq.push_back(*a); + if (is_order_function((*a).rest)) + break; + ++a; + } else if (pow_b < pow_a) { + // b has lesser power, get coefficient from b + new_seq.push_back(*b); + if (is_order_function((*b).rest)) + break; + ++b; + } else { + // Add coefficient of a and b + if (is_order_function((*a).rest) || is_order_function((*b).rest)) { + new_seq.push_back(expair(Order(_ex1), (*a).coeff)); + break; // Order term ends the sequence + } else { + ex sum = (*a).rest + (*b).rest; + if (!(sum.is_zero())) + new_seq.push_back(expair(sum, numeric(pow_a))); + ++a; + ++b; + } + } + } + return pseries(relational(var,point), new_seq); } /** Implementation of ex::series() for sums. This performs series addition when * adding pseries objects. * @see ex::series */ -ex add::series(const symbol & s, const ex & point, int order) const -{ - ex acc; // Series accumulator - - // Get first term from overall_coeff - acc = overall_coeff.series(s, point, order); - - // Add remaining terms - epvector::const_iterator it = seq.begin(); - epvector::const_iterator itend = seq.end(); - for (; it!=itend; it++) { - ex op; - if (is_ex_exactly_of_type(it->rest, pseries)) - op = it->rest; - else - op = it->rest.series(s, point, order); - if (!it->coeff.is_equal(_ex1())) - op = ex_to_pseries(op).mul_const(ex_to_numeric(it->coeff)); - - // Series addition - acc = ex_to_pseries(acc).add_series(ex_to_pseries(op)); - } - return acc; +ex add::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); + + // Add remaining terms + epvector::const_iterator it = seq.begin(); + epvector::const_iterator itend = seq.end(); + for (; it!=itend; ++it) { + ex op; + if (is_exactly_a(it->rest)) + op = it->rest; + else + op = it->rest.series(r, order, options); + if (!it->coeff.is_equal(_ex1)) + op = ex_to(op).mul_const(ex_to(it->coeff)); + + // Series addition + acc = ex_to(acc).add_series(ex_to(op)); + } + return acc; } @@ -513,18 +808,18 @@ ex add::series(const symbol & s, const ex & point, int order) const * @return the product as a pseries */ ex pseries::mul_const(const numeric &other) const { - epvector new_seq; - new_seq.reserve(seq.size()); - - epvector::const_iterator it = seq.begin(), itend = seq.end(); - while (it != itend) { - if (!is_order_function(it->rest)) - new_seq.push_back(expair(it->rest * other, it->coeff)); - else - new_seq.push_back(*it); - it++; - } - return pseries(var, point, new_seq); + epvector new_seq; + new_seq.reserve(seq.size()); + + epvector::const_iterator it = seq.begin(), itend = seq.end(); + while (it != itend) { + if (!is_order_function(it->rest)) + new_seq.push_back(expair(it->rest * other, it->coeff)); + else + new_seq.push_back(*it); + ++it; + } + return pseries(relational(var,point), new_seq); } @@ -535,82 +830,168 @@ ex pseries::mul_const(const numeric &other) const * @return the product as a pseries */ ex pseries::mul_series(const pseries &other) const { - // Multiplying two series with different variables or expansion points - // results in an empty (constant) series - if (!is_compatible_to(other)) { - epvector nul; - nul.push_back(expair(Order(_ex1()), _ex0())); - return pseries(var, point, nul); - } - - // Series multiplication - epvector new_seq; - - const symbol *s = static_cast(var.bp); - int a_max = degree(*s); - int b_max = other.degree(*s); - int a_min = ldegree(*s); - int b_min = other.ldegree(*s); - int cdeg_min = a_min + b_min; - int cdeg_max = a_max + b_max; - - int higher_order_a = INT_MAX; - int higher_order_b = INT_MAX; - if (is_order_function(coeff(*s, a_max))) - higher_order_a = a_max + b_min; - if (is_order_function(other.coeff(*s, b_max))) - higher_order_b = b_max + a_min; - int higher_order_c = min(higher_order_a, higher_order_b); - if (cdeg_max >= higher_order_c) - cdeg_max = higher_order_c - 1; - - for (int cdeg=cdeg_min; cdeg<=cdeg_max; cdeg++) { - ex co = _ex0(); - // c(i)=a(0)b(i)+...+a(i)b(0) - for (int i=a_min; cdeg-i>=b_min; i++) { - ex a_coeff = coeff(*s, i); - ex b_coeff = other.coeff(*s, cdeg-i); - if (!is_order_function(a_coeff) && !is_order_function(b_coeff)) - co += coeff(*s, i) * other.coeff(*s, cdeg-i); - } - if (!co.is_zero()) - new_seq.push_back(expair(co, numeric(cdeg))); - } - if (higher_order_c < INT_MAX) - new_seq.push_back(expair(Order(_ex1()), numeric(higher_order_c))); - return pseries(var, point, new_seq); + // Multiplying two series with different variables or expansion points + // results in an empty (constant) series + if (!is_compatible_to(other)) { + epvector nul; + nul.push_back(expair(Order(_ex1), _ex0)); + return pseries(relational(var,point), nul); + } + + if (seq.empty() || other.seq.empty()) { + return (new pseries(var==point, epvector())) + ->setflag(status_flags::dynallocated); + } + + // Series multiplication + epvector new_seq; + int a_max = degree(var); + int b_max = other.degree(var); + int a_min = ldegree(var); + int b_min = other.ldegree(var); + int cdeg_min = a_min + b_min; + int cdeg_max = a_max + b_max; + + int higher_order_a = std::numeric_limits::max(); + int higher_order_b = std::numeric_limits::max(); + if (is_order_function(coeff(var, a_max))) + higher_order_a = a_max + b_min; + if (is_order_function(other.coeff(var, b_max))) + higher_order_b = b_max + a_min; + int higher_order_c = std::min(higher_order_a, higher_order_b); + if (cdeg_max >= higher_order_c) + cdeg_max = higher_order_c - 1; + + for (int cdeg=cdeg_min; cdeg<=cdeg_max; ++cdeg) { + ex co = _ex0; + // c(i)=a(0)b(i)+...+a(i)b(0) + for (int i=a_min; cdeg-i>=b_min; ++i) { + ex a_coeff = coeff(var, i); + ex b_coeff = other.coeff(var, cdeg-i); + if (!is_order_function(a_coeff) && !is_order_function(b_coeff)) + co += a_coeff * b_coeff; + } + if (!co.is_zero()) + new_seq.push_back(expair(co, numeric(cdeg))); + } + if (higher_order_c < std::numeric_limits::max()) + new_seq.push_back(expair(Order(_ex1), numeric(higher_order_c))); + return pseries(relational(var, point), new_seq); } /** Implementation of ex::series() for product. This performs series * multiplication when multiplying series. * @see ex::series */ -ex mul::series(const symbol & s, const ex & point, int order) const -{ - ex acc; // Series accumulator - - // Get first term from overall_coeff - acc = overall_coeff.series(s, point, order); - - // Multiply with remaining terms - epvector::const_iterator it = seq.begin(); - epvector::const_iterator itend = seq.end(); - for (; 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)) - op = op.series(s, point, order); - 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)); - } - return acc; +ex mul::series(const relational & r, int order, unsigned options) const +{ + pseries acc; // Series accumulator + + GINAC_ASSERT(is_a(r.lhs())); + const ex& sym = r.lhs(); + + // holds ldegrees of the series of individual factors + std::vector ldegrees; + std::vector ldegree_redo; + + // find minimal degrees + const epvector::const_iterator itbeg = seq.begin(); + const epvector::const_iterator itend = seq.end(); + // first round: obtain a bound up to which minimal degrees have to be + // considered + for (epvector::const_iterator it=itbeg; it!=itend; ++it) { + + ex expon = it->coeff; + int factor = 1; + ex buf; + if (expon.info(info_flags::integer)) { + buf = it->rest; + factor = ex_to(expon).to_int(); + } else { + buf = recombine_pair_to_ex(*it); + } + + int real_ldegree = 0; + bool flag_redo = false; + try { + real_ldegree = buf.expand().ldegree(sym-r.rhs()); + } catch (std::runtime_error) {} + + if (real_ldegree == 0) { + if ( factor < 0 ) { + // This case must terminate, otherwise we would have division by + // zero. + int orderloop = 0; + do { + orderloop++; + real_ldegree = buf.series(r, orderloop, options).ldegree(sym); + } while (real_ldegree == orderloop); + } else { + // Here it is possible that buf does not have a ldegree, therefore + // check only if ldegree is negative, otherwise reconsider the case + // in the second round. + real_ldegree = buf.series(r, 0, options).ldegree(sym); + if (real_ldegree == 0) + flag_redo = true; + } + } + + ldegrees.push_back(factor * real_ldegree); + ldegree_redo.push_back(flag_redo); + } + + int degbound = order-std::accumulate(ldegrees.begin(), ldegrees.end(), 0); + // Second round: determine the remaining positive ldegrees by the series + // method. + // here we can ignore ldegrees larger than degbound + size_t j = 0; + for (epvector::const_iterator it=itbeg; it!=itend; ++it) { + if ( ldegree_redo[j] ) { + ex expon = it->coeff; + int factor = 1; + ex buf; + if (expon.info(info_flags::integer)) { + buf = it->rest; + factor = ex_to(expon).to_int(); + } else { + buf = recombine_pair_to_ex(*it); + } + int real_ldegree = 0; + int orderloop = 0; + do { + orderloop++; + real_ldegree = buf.series(r, orderloop, options).ldegree(sym); + } while ((real_ldegree == orderloop) + && ( factor*real_ldegree < degbound)); + ldegrees[j] = factor * real_ldegree; + degbound -= factor * real_ldegree; + } + j++; + } + + int degsum = std::accumulate(ldegrees.begin(), ldegrees.end(), 0); + + if (degsum >= order) { + epvector epv; + epv.push_back(expair(Order(_ex1), order)); + return (new pseries(r, epv))->setflag(status_flags::dynallocated); + } + + // Multiply with remaining terms + std::vector::const_iterator itd = ldegrees.begin(); + for (epvector::const_iterator it=itbeg; it!=itend; ++it, ++itd) { + + // do series expansion with adjusted order + ex op = recombine_pair_to_ex(*it).series(r, order-degsum+(*itd), options); + + // Series multiplication + if (it == itbeg) + acc = ex_to(op); + else + acc = ex_to(acc.mul_series(ex_to(op))); + } + + return acc.mul_const(ex_to(overall_coeff)); } @@ -620,95 +1001,312 @@ ex mul::series(const symbol & s, const ex & point, int order) const * @param deg truncation order of series calculation */ ex pseries::power_const(const numeric &p, int deg) const { - int i; - const symbol *s = static_cast(var.bp); - int ldeg = ldegree(*s); - - // Calculate coefficients of powered series - exvector co; - co.reserve(deg); - ex co0; - co.push_back(co0 = power(coeff(*s, ldeg), p)); - bool all_sums_zero = true; - for (i=1; isetflag(status_flags::dynallocated); + } + + // O(x^n)^(-m) is undefined + if (seq.size() == 1 && is_order_function(seq[0].rest) && p.real().is_negative()) + throw pole_error("pseries::power_const(): division by zero",1); + + // Compute coefficients of the powered series + exvector co; + co.reserve(numcoeff); + co.push_back(power(coeff(var, ldeg), p)); + for (int i=1; icoeff += deg; + ++i; + } + return pseries(relational(var, point), newseq); } /** Implementation of ex::series() for powers. This performs Laurent expansion * of reciprocals of series at singularities. * @see ex::series */ -ex power::series(const symbol & s, const ex & point, int order) const -{ - ex e; - if (!is_ex_exactly_of_type(basis, pseries)) { - // Basis is not a series, may there be a singulary? - if (!exponent.info(info_flags::negint)) - return basic::series(s, point, order); - - // Expression is of type something^(-int), check for singularity - if (!basis.subs(s == point).is_zero()) - return basic::series(s, point, order); - - // Singularity encountered, expand basis into series - e = basis.series(s, point, order); - } else { - // Basis is a series - e = basis; - } - - // Power e - return ex_to_pseries(e).power_const(ex_to_numeric(exponent), order); +ex power::series(const relational & r, int order, unsigned options) const +{ + // If basis is already a series, just power it + if (is_exactly_a(basis)) + return ex_to(basis).power_const(ex_to(exponent), order); + + // Basis is not a series, may there be a singularity? + bool must_expand_basis = false; + try { + basis.subs(r, subs_options::no_pattern); + } catch (pole_error) { + must_expand_basis = true; + } + + bool exponent_is_regular = true; + try { + exponent.subs(r, subs_options::no_pattern); + } catch (pole_error) { + exponent_is_regular = false; + } + + if (!exponent_is_regular) { + ex l = exponent*log(basis); + // this == exp(l); + ex le = l.series(r, order, options); + // Note: expanding exp(l) won't help, since that will attempt + // Taylor expansion, and fail (because exponent is "singular") + // Still l itself might be expanded in Taylor series. + // Examples: + // sin(x)/x*log(cos(x)) + // 1/x*log(1 + x) + return exp(le).series(r, order, options); + // Note: if l happens to have a Laurent expansion (with + // negative powers of (var - point)), expanding exp(le) + // will barf (which is The Right Thing). + } + + // Is the expression of type something^(-int)? + if (!must_expand_basis && !exponent.info(info_flags::negint) + && (!is_a(basis) || !is_a(exponent))) + return basic::series(r, order, options); + + // Is the expression of type 0^something? + if (!must_expand_basis && !basis.subs(r, subs_options::no_pattern).is_zero() + && (!is_a(basis) || !is_a(exponent))) + return basic::series(r, order, options); + + // Singularity encountered, is the basis equal to (var - point)? + if (basis.is_equal(r.lhs() - r.rhs())) { + epvector new_seq; + if (ex_to(exponent).to_int() < order) + new_seq.push_back(expair(_ex1, exponent)); + else + new_seq.push_back(expair(Order(_ex1), exponent)); + return pseries(r, new_seq); + } + + // No, expand basis into series + + numeric numexp; + if (is_a(exponent)) { + numexp = ex_to(exponent); + } else { + numexp = 0; + } + const ex& sym = r.lhs(); + // find existing minimal degree + ex eb = basis.expand(); + int real_ldegree = 0; + if (eb.info(info_flags::rational_function)) + real_ldegree = eb.ldegree(sym-r.rhs()); + if (real_ldegree == 0) { + int orderloop = 0; + do { + orderloop++; + real_ldegree = basis.series(r, orderloop, options).ldegree(sym); + } while (real_ldegree == orderloop); + } + + if (!(real_ldegree*numexp).is_integer()) + throw std::runtime_error("pseries::power_const(): trying to assemble a Puiseux series"); + ex e = basis.series(r, (order + real_ldegree*(1-numexp)).to_int(), options); + + ex result; + try { + result = ex_to(e).power_const(numexp, order); + } catch (pole_error) { + epvector ser; + ser.push_back(expair(Order(_ex1), order)); + result = pseries(r, ser); + } + + return result; +} + + +/** Re-expansion of a pseries object. */ +ex pseries::series(const relational & r, int order, unsigned options) const +{ + const ex p = r.rhs(); + GINAC_ASSERT(is_a(r.lhs())); + const symbol &s = ex_to(r.lhs()); + + if (var.is_equal(s) && point.is_equal(p)) { + if (order > degree(s)) + return *this; + else { + epvector new_seq; + epvector::const_iterator it = seq.begin(), itend = seq.end(); + while (it != itend) { + int o = ex_to(it->coeff).to_int(); + if (o >= order) { + new_seq.push_back(expair(Order(_ex1), o)); + break; + } + new_seq.push_back(*it); + ++it; + } + return pseries(r, new_seq); + } + } else + return convert_to_poly().series(r, order, options); +} + +ex integral::series(const relational & r, int order, unsigned options) const +{ + if (x.subs(r) != x) + throw std::logic_error("Cannot series expand wrt dummy variable"); + + // Expanding integrant with r substituted taken in boundaries. + ex fseries = f.series(r, order, options); + epvector fexpansion; + fexpansion.reserve(fseries.nops()); + for (size_t i=0; i(fseries).coeffop(i); + currcoeff = (currcoeff == Order(_ex1)) + ? currcoeff + : integral(x, a.subs(r), b.subs(r), currcoeff); + if (currcoeff != 0) + fexpansion.push_back( + expair(currcoeff, ex_to(fseries).exponop(i))); + } + + // Expanding lower boundary + ex result = (new pseries(r, fexpansion))->setflag(status_flags::dynallocated); + ex aseries = (a-a.subs(r)).series(r, order, options); + fseries = f.series(x == (a.subs(r)), order, options); + for (size_t i=0; i(fseries).coeffop(i); + if (is_order_function(currcoeff)) + break; + ex currexpon = ex_to(fseries).exponop(i); + int orderforf = order-ex_to(currexpon).to_int()-1; + currcoeff = currcoeff.series(r, orderforf); + ex term = ex_to(aseries).power_const(ex_to(currexpon+1),order); + term = ex_to(term).mul_const(ex_to(-1/(currexpon+1))); + term = ex_to(term).mul_series(ex_to(currcoeff)); + result = ex_to(result).add_series(ex_to(term)); + } + + // Expanding upper boundary + ex bseries = (b-b.subs(r)).series(r, order, options); + fseries = f.series(x == (b.subs(r)), order, options); + for (size_t i=0; i(fseries).coeffop(i); + if (is_order_function(currcoeff)) + break; + ex currexpon = ex_to(fseries).exponop(i); + int orderforf = order-ex_to(currexpon).to_int()-1; + currcoeff = currcoeff.series(r, orderforf); + ex term = ex_to(bseries).power_const(ex_to(currexpon+1),order); + term = ex_to(term).mul_const(ex_to(1/(currexpon+1))); + term = ex_to(term).mul_series(ex_to(currcoeff)); + result = ex_to(result).add_series(ex_to(term)); + } + + return result; } /** Compute the truncated series expansion of an expression. - * This function returns an expression containing an object of class pseries to - * represent the series. If the series does not terminate within the given + * This function returns an expression containing an object of class pseries + * to represent the series. If the series does not terminate within the given * truncation order, the last term of the series will be an order term. * - * @param s expansion variable - * @param point expansion point + * @param r expansion relation, lhs holds variable and rhs holds point * @param order truncation order of series calculations + * @param options of class series_options * @return an expression holding a pseries object */ -ex ex::series(const symbol &s, const ex &point, int order) const +ex ex::series(const ex & r, int order, unsigned options) const { - GINAC_ASSERT(bp!=0); - return bp->series(s, point, order); + ex e; + relational rel_; + + if (is_a(r)) + rel_ = ex_to(r); + else if (is_a(r)) + rel_ = relational(r,_ex0); + else + throw (std::logic_error("ex::series(): expansion point has unknown type")); + + e = bp->series(rel_, order, options); + return e; } +GINAC_BIND_UNARCHIVER(pseries); -// Global constants -const pseries some_pseries; -const type_info & typeid_pseries = typeid(some_pseries); - -#ifndef NO_NAMESPACE_GINAC } // namespace GiNaC -#endif // ndef NO_NAMESPACE_GINAC