void StrPrinter::bvisit(const FunctionSymbol &x) {
std::ostringstream o;
o << x.get_name();
o << "(";
vec_basic vec = x.get_args();
o << this->apply(vec) << ")";
str_ = o.str();
}
static RCP<const Basic> diff(const FunctionSymbol &self,
const RCP<const Symbol> &x) {
RCP<const Basic> diff = zero, t;
RCP<const Basic> self_ = self.rcp_from_this();
RCP<const Symbol> s;
std::string name;
unsigned count = 0;
bool found_x = false;
for (const auto &a : self.get_args()) {
if (eq(*a, *x)) {
found_x = true;
count++;
} else if (count < 2 and neq(*a->diff(x), *zero)) {
count++;
}
}
if (count == 1 and found_x) {
return Derivative::create(self_, {x});
}
for (unsigned i = 0; i < self.get_args().size(); i++) {
t = self.get_args()[i]->diff(x);
if (neq(*t, *zero)) {
name = "x";
do {
name = "_" + name;
s = symbol(name);
} while (has_symbol(*self_, s));
vec_basic v = self.get_args();
v[i] = s;
map_basic_basic m;
insert(m, v[i], self.get_args()[i]);
diff = add(diff, mul(t,
make_rcp<const Subs>(Derivative::create(self.create(v),
{v[i]}), m)));
}
}
return diff;
}