ex.cpp

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/*
 *  GiNaC Copyright (C) 1999-2011 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
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "ex.h"
#include "add.h"
#include "mul.h"
#include "ncmul.h"
#include "numeric.h"
#include "matrix.h"
#include "power.h"
#include "lst.h"
#include "relational.h"
#include "utils.h"

#include <iostream>
#include <stdexcept>

namespace GiNaC {

// other constructors

// none (all inlined)

// non-virtual functions in this class

// public
    
void ex::print(const print_context & c, unsigned level) const
{
    bp->print(c, level);
}

void ex::dbgprint() const
{
    bp->dbgprint();
}

void ex::dbgprinttree() const
{
    bp->dbgprinttree();
}

ex ex::expand(unsigned options) const
{
    if (options == 0 && (bp->flags & status_flags::expanded)) // The "expanded" flag only covers the standard options; someone might want to re-expand with different options
        return *this;
    else
        return bp->expand(options);
}

ex ex::diff(const symbol & s, unsigned nth) const
{
    if (!nth)
        return *this;
    else
        return bp->diff(s, nth);
}

bool ex::match(const ex & pattern) const
{
    exmap repl_lst;
    return bp->match(pattern, repl_lst);
}

bool ex::find(const ex & pattern, exset& found) const
{
    if (match(pattern)) {
        found.insert(*this);
        return true;
    }
    bool any_found = false;
    for (size_t i=0; i<nops(); i++)
        if (op(i).find(pattern, found))
            any_found = true;
    return any_found;
}

ex ex::subs(const lst & ls, const lst & lr, unsigned options) const
{
    GINAC_ASSERT(ls.nops() == lr.nops());

    // Convert the lists to a map
    exmap m;
    for (lst::const_iterator its = ls.begin(), itr = lr.begin(); its != ls.end(); ++its, ++itr) {
        m.insert(std::make_pair(*its, *itr));

        // Search for products and powers in the expressions to be substituted
        // (for an optimization in expairseq::subs())
        if (is_exactly_a<mul>(*its) || is_exactly_a<power>(*its))
            options |= subs_options::pattern_is_product;
    }
    if (!(options & subs_options::pattern_is_product))
        options |= subs_options::pattern_is_not_product;

    return bp->subs(m, options);
}

ex ex::subs(const ex & e, unsigned options) const
{
    if (e.info(info_flags::relation_equal)) {

        // Argument is a relation: convert it to a map
        exmap m;
        const ex & s = e.op(0);
        m.insert(std::make_pair(s, e.op(1)));

        if (is_exactly_a<mul>(s) || is_exactly_a<power>(s))
            options |= subs_options::pattern_is_product;
        else
            options |= subs_options::pattern_is_not_product;

        return bp->subs(m, options);

    } else if (e.info(info_flags::list)) {

        // Argument is a list: convert it to a map
        exmap m;
        GINAC_ASSERT(is_a<lst>(e));
        for (lst::const_iterator it = ex_to<lst>(e).begin(); it != ex_to<lst>(e).end(); ++it) {
            ex r = *it;
            if (!r.info(info_flags::relation_equal))
                throw(std::invalid_argument("basic::subs(ex): argument must be a list of equations"));
            const ex & s = r.op(0);
            m.insert(std::make_pair(s, r.op(1)));

            // Search for products and powers in the expressions to be substituted
            // (for an optimization in expairseq::subs())
            if (is_exactly_a<mul>(s) || is_exactly_a<power>(s))
                options |= subs_options::pattern_is_product;
        }
        if (!(options & subs_options::pattern_is_product))
            options |= subs_options::pattern_is_not_product;

        return bp->subs(m, options);

    } else
        throw(std::invalid_argument("ex::subs(ex): argument must be a relation_equal or a list"));
}

void ex::traverse_preorder(visitor & v) const
{
    accept(v);

    size_t n = nops();
    for (size_t i = 0; i < n; ++i)
        op(i).traverse_preorder(v);
}

void ex::traverse_postorder(visitor & v) const
{
    size_t n = nops();
    for (size_t i = 0; i < n; ++i)
        op(i).traverse_postorder(v);

    accept(v);
}

ex & ex::let_op(size_t i)
{
    makewriteable();
    return bp->let_op(i);
}

ex & ex::operator[](const ex & index)
{
    makewriteable();
    return (*bp)[index];
}

ex & ex::operator[](size_t i)
{
    makewriteable();
    return (*bp)[i];
}

ex ex::lhs() const
{
    if (!is_a<relational>(*this))
        throw std::runtime_error("ex::lhs(): not a relation");
    return bp->op(0);
}

ex ex::rhs() const
{
    if (!is_a<relational>(*this))
        throw std::runtime_error("ex::rhs(): not a relation");
    return bp->op(1);
}

bool ex::is_polynomial(const ex & vars) const
{
    if (is_a<lst>(vars)) {
        const lst & varlst = ex_to<lst>(vars);
        for (lst::const_iterator i=varlst.begin(); i!=varlst.end(); ++i)
            if (!bp->is_polynomial(*i))
                return false;
        return true;
    }
    else
        return bp->is_polynomial(vars);
}

bool ex::is_zero_matrix() const
{
    if (is_zero())
        return  true;
    else {
        ex e = evalm();
        return is_a<matrix>(e) && ex_to<matrix>(e).is_zero_matrix();
    }
}

// private

void ex::makewriteable()
{
    GINAC_ASSERT(bp->flags & status_flags::dynallocated);
    bp.makewritable();
    GINAC_ASSERT(bp->get_refcount() == 1);
}

void ex::share(const ex & other) const
{
    if ((bp->flags | other.bp->flags) & status_flags::not_shareable)
        return;

    if (bp->get_refcount() <= other.bp->get_refcount())
        bp = other.bp;
    else
        other.bp = bp;
}

ptr<basic> ex::construct_from_basic(const basic & other)
{
    if (!(other.flags & status_flags::evaluated)) {

        // The object is not yet evaluated, so call eval() to evaluate
        // the top level. This will return either
        //  a) the original object with status_flags::evaluated set (when the
        //     eval() implementation calls hold())
        // or
        //  b) a different expression.
        //
        // eval() returns an ex, not a basic&, so this will go through
        // construct_from_basic() a second time. In case a) we end up in
        // the "else" branch below. In case b) we end up here again and
        // apply eval() once more. The recursion stops when eval() calls
        // hold() or returns an object that already has its "evaluated"
        // flag set, such as a symbol or a numeric.
        const ex & tmpex = other.eval(1);

        // Eventually, the eval() recursion goes through the "else" branch
        // below, which assures that the object pointed to by tmpex.bp is
        // allocated on the heap (either it was already on the heap or it
        // is a heap-allocated duplicate of another object).
        GINAC_ASSERT(tmpex.bp->flags & status_flags::dynallocated); 

        // If the original object is not referenced but heap-allocated,
        // it means that eval() hit case b) above. The original object is
        // no longer needed (it evaluated into something different), so we
        // delete it (because nobody else will).
        if ((other.get_refcount() == 0) && (other.flags & status_flags::dynallocated))
            delete &other; // yes, you can apply delete to a const pointer

        // We can't return a basic& here because the tmpex is destroyed as
        // soon as we leave the function, which would deallocate the
        // evaluated object.
        return tmpex.bp;

    } else {

        // The easy case: making an "ex" out of an evaluated object.
        if (other.flags & status_flags::dynallocated) {

            // The object is already heap-allocated, so we can just make
            // another reference to it.
            return ptr<basic>(const_cast<basic &>(other));

        } else {

            // The object is not heap-allocated, so we create a duplicate
            // on the heap.
            basic *bp = other.duplicate();
            bp->setflag(status_flags::dynallocated);
            GINAC_ASSERT(bp->get_refcount() == 0);
            return bp;
        }
    }
}

basic & ex::construct_from_int(int i)
{
    switch (i) {  // prefer flyweights over new objects
    case -12:
        return *const_cast<numeric *>(_num_12_p);
    case -11:
        return *const_cast<numeric *>(_num_11_p);
    case -10:
        return *const_cast<numeric *>(_num_10_p);
    case -9:
        return *const_cast<numeric *>(_num_9_p);
    case -8:
        return *const_cast<numeric *>(_num_8_p);
    case -7:
        return *const_cast<numeric *>(_num_7_p);
    case -6:
        return *const_cast<numeric *>(_num_6_p);
    case -5:
        return *const_cast<numeric *>(_num_5_p);
    case -4:
        return *const_cast<numeric *>(_num_4_p);
    case -3:
        return *const_cast<numeric *>(_num_3_p);
    case -2:
        return *const_cast<numeric *>(_num_2_p);
    case -1:
        return *const_cast<numeric *>(_num_1_p);
    case 0:
        return *const_cast<numeric *>(_num0_p);
    case 1:
        return *const_cast<numeric *>(_num1_p);
    case 2:
        return *const_cast<numeric *>(_num2_p);
    case 3:
        return *const_cast<numeric *>(_num3_p);
    case 4:
        return *const_cast<numeric *>(_num4_p);
    case 5:
        return *const_cast<numeric *>(_num5_p);
    case 6:
        return *const_cast<numeric *>(_num6_p);
    case 7:
        return *const_cast<numeric *>(_num7_p);
    case 8:
        return *const_cast<numeric *>(_num8_p);
    case 9:
        return *const_cast<numeric *>(_num9_p);
    case 10:
        return *const_cast<numeric *>(_num10_p);
    case 11:
        return *const_cast<numeric *>(_num11_p);
    case 12:
        return *const_cast<numeric *>(_num12_p);
    default:
        basic *bp = new numeric(i);
        bp->setflag(status_flags::dynallocated);
        GINAC_ASSERT(bp->get_refcount() == 0);
        return *bp;
    }
}
    
basic & ex::construct_from_uint(unsigned int i)
{
    switch (i) {  // prefer flyweights over new objects
    case 0:
        return *const_cast<numeric *>(_num0_p);
    case 1:
        return *const_cast<numeric *>(_num1_p);
    case 2:
        return *const_cast<numeric *>(_num2_p);
    case 3:
        return *const_cast<numeric *>(_num3_p);
    case 4:
        return *const_cast<numeric *>(_num4_p);
    case 5:
        return *const_cast<numeric *>(_num5_p);
    case 6:
        return *const_cast<numeric *>(_num6_p);
    case 7:
        return *const_cast<numeric *>(_num7_p);
    case 8:
        return *const_cast<numeric *>(_num8_p);
    case 9:
        return *const_cast<numeric *>(_num9_p);
    case 10:
        return *const_cast<numeric *>(_num10_p);
    case 11:
        return *const_cast<numeric *>(_num11_p);
    case 12:
        return *const_cast<numeric *>(_num12_p);
    default:
        basic *bp = new numeric(i);
        bp->setflag(status_flags::dynallocated);
        GINAC_ASSERT(bp->get_refcount() == 0);
        return *bp;
    }
}
    
basic & ex::construct_from_long(long i)
{
    switch (i) {  // prefer flyweights over new objects
    case -12:
        return *const_cast<numeric *>(_num_12_p);
    case -11:
        return *const_cast<numeric *>(_num_11_p);
    case -10:
        return *const_cast<numeric *>(_num_10_p);
    case -9:
        return *const_cast<numeric *>(_num_9_p);
    case -8:
        return *const_cast<numeric *>(_num_8_p);
    case -7:
        return *const_cast<numeric *>(_num_7_p);
    case -6:
        return *const_cast<numeric *>(_num_6_p);
    case -5:
        return *const_cast<numeric *>(_num_5_p);
    case -4:
        return *const_cast<numeric *>(_num_4_p);
    case -3:
        return *const_cast<numeric *>(_num_3_p);
    case -2:
        return *const_cast<numeric *>(_num_2_p);
    case -1:
        return *const_cast<numeric *>(_num_1_p);
    case 0:
        return *const_cast<numeric *>(_num0_p);
    case 1:
        return *const_cast<numeric *>(_num1_p);
    case 2:
        return *const_cast<numeric *>(_num2_p);
    case 3:
        return *const_cast<numeric *>(_num3_p);
    case 4:
        return *const_cast<numeric *>(_num4_p);
    case 5:
        return *const_cast<numeric *>(_num5_p);
    case 6:
        return *const_cast<numeric *>(_num6_p);
    case 7:
        return *const_cast<numeric *>(_num7_p);
    case 8:
        return *const_cast<numeric *>(_num8_p);
    case 9:
        return *const_cast<numeric *>(_num9_p);
    case 10:
        return *const_cast<numeric *>(_num10_p);
    case 11:
        return *const_cast<numeric *>(_num11_p);
    case 12:
        return *const_cast<numeric *>(_num12_p);
    default:
        basic *bp = new numeric(i);
        bp->setflag(status_flags::dynallocated);
        GINAC_ASSERT(bp->get_refcount() == 0);
        return *bp;
    }
}
    
basic & ex::construct_from_ulong(unsigned long i)
{
    switch (i) {  // prefer flyweights over new objects
    case 0:
        return *const_cast<numeric *>(_num0_p);
    case 1:
        return *const_cast<numeric *>(_num1_p);
    case 2:
        return *const_cast<numeric *>(_num2_p);
    case 3:
        return *const_cast<numeric *>(_num3_p);
    case 4:
        return *const_cast<numeric *>(_num4_p);
    case 5:
        return *const_cast<numeric *>(_num5_p);
    case 6:
        return *const_cast<numeric *>(_num6_p);
    case 7:
        return *const_cast<numeric *>(_num7_p);
    case 8:
        return *const_cast<numeric *>(_num8_p);
    case 9:
        return *const_cast<numeric *>(_num9_p);
    case 10:
        return *const_cast<numeric *>(_num10_p);
    case 11:
        return *const_cast<numeric *>(_num11_p);
    case 12:
        return *const_cast<numeric *>(_num12_p);
    default:
        basic *bp = new numeric(i);
        bp->setflag(status_flags::dynallocated);
        GINAC_ASSERT(bp->get_refcount() == 0);
        return *bp;
    }
}
    
basic & ex::construct_from_double(double d)
{
    basic *bp = new numeric(d);
    bp->setflag(status_flags::dynallocated);
    GINAC_ASSERT(bp->get_refcount() == 0);
    return *bp;
}

// static member variables

// none

// functions which are not member functions

// none

// global functions

// none


} // namespace GiNaC