ex pseries::coeff(const symbol &s, int n) 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();
+ if (seq.size() == 0)
+ 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_ex_exactly_of_type(seq[mid].coeff, numeric));
+ int cmp = ex_to_numeric(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::collect(const symbol &s) const
{
- if (var.is_equal(s))
- return convert_to_poly();
- else
- return inherited::collect(s);
+ return *this;
}
+/** Evaluate coefficients. */
ex pseries::eval(int level) const
{
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;
return (new pseries(var, point, new_seq))->setflag(status_flags::dynallocated | status_flags::evaluated);
}
-/** Evaluate numerically. The order term is dropped. */
+/** 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(var, point, new_seq))->setflag(status_flags::dynallocated | status_flags::evaluated);
}
ex pseries::subs(const lst & ls, const lst & lr) const
ex ex::series(const symbol &s, const ex &point, int order) const
{
GINAC_ASSERT(bp!=0);
- return bp->series(s, point, order);
+ ex e;
+ try {
+ e = bp->series(s, point, order);
+ } catch (exception &x) {
+ throw (std::logic_error(string("unable to compute series (") + x.what() + ")"));
+ }
+ return e;
}