def is_finite(self):
"""
The Cartesian product is finite if all of its inputs are
finite, or if any input is empty.
EXAMPLES::
sage: from sage.combinat.cartesian_product import CartesianProduct_iters
sage: CartesianProduct_iters(ZZ, []).is_finite()
True
sage: CartesianProduct_iters(4,4).is_finite()
Traceback (most recent call last):
...
ValueError: Unable to determine whether this product is finite
"""
finites = [_is_finite(L, fallback=None) for L in self.iters]
if any(f is None for f in finites):
raise ValueError(
"Unable to determine whether this product is finite")
if all(f is True for f in finites):
return True
lens = [_len(L) for L in self.iters]
if any(l == 0 for l in lens):
return True
return False
def is_finite(self):
"""
The cartesian product is finite if all of its inputs are
finite, or if any input is empty.
EXAMPLES::
sage: CartesianProduct(ZZ, []).is_finite()
True
sage: CartesianProduct(4,4).is_finite()
Traceback (most recent call last):
...
ValueError: Unable to determine whether this product is finite
"""
finites = [_is_finite(L, fallback=None) for L in self.iters]
if any(f is None for f in finites):
raise ValueError("Unable to determine whether this product is finite")
if all(f is True for f in finites):
return True
lens = [_len(L) for L in self.iters]
if any(l == 0 for l in lens):
return True
return False