def is_quasiconcave(self):
"""Is the expression quasiconcave?
"""
# Verifies the DQCP composition rule.
if self.is_concave():
return True
if type(self) == cvxtypes.minimum():
return all(arg.is_quasiconcave() for arg in self.args)
non_const = self._non_const_idx()
if self.is_scalar() and len(non_const) == 1 and self.is_incr(non_const[0]):
return self.args[non_const[0]].is_quasiconcave()
if self.is_scalar() and len(non_const) == 1 and self.is_decr(non_const[0]):
return self.args[non_const[0]].is_quasiconvex()
if self.is_atom_quasiconcave():
for idx, arg in enumerate(self.args):
if not (arg.is_affine() or
(arg.is_concave() and self.is_incr(idx)) or
(arg.is_convex() and self.is_decr(idx))):
return False
return True
return False
def is_quasiconcave(self) -> bool:
"""Is the expression quasiconcave?
"""
from cvxpy.atoms.min import min as min_atom
# Verifies the DQCP composition rule.
if self.is_concave():
return True
if type(self) in (cvxtypes.minimum(), min_atom):
return all(arg.is_quasiconcave() for arg in self.args)
non_const = self._non_const_idx()
if self._is_real() and self.is_incr(non_const[0]):
return self.args[non_const[0]].is_quasiconcave()
if self._is_real() and self.is_decr(non_const[0]):
return self.args[non_const[0]].is_quasiconvex()
if self.is_atom_quasiconcave():
for idx, arg in enumerate(self.args):
if not (arg.is_affine() or
(arg.is_concave() and self.is_incr(idx)) or
(arg.is_convex() and self.is_decr(idx))):
return False
return True
return False
