# Source code for psdr.domains.box

from __future__ import division

import numpy as np
from scipy.spatial.distance import pdist

from .domain import TOL
from .linineq import LinIneqDomain
from ..exceptions import EmptyDomainException

[docs]class BoxDomain(LinIneqDomain):
r""" Implements a domain specified by box constraints

Given a set of lower and upper bounds, this class defines the domain

.. math::

\mathcal{D} := \lbrace \mathbf{x} \in \mathbb{R}^m : \text{lb} \le \mathbf{x} \le \text{ub} \rbrace \subset \mathbb{R}^m.

Parameters
----------
lb: array-like (m,)
Lower bounds
ub: array-like (m,)
Upper bounds
"""
def __init__(self, lb, ub, names = None):
LinIneqDomain.__init__(self, lb = lb, ub = ub, names = names)
#assert np.all(np.isfinite(lb)) and np.all(np.isfinite(ub)), "Both lb and ub must be finite to construct a box domain"

@property
def is_empty(self):
try:
return self._empty
except AttributeError:
self._empty = np.any(self.lb > self.ub)
self._point = False
self._unbounded = False
return self._empty

@property
def is_point(self):
try:
return self._point
except AttributeError:
self._point = np.all(np.abs(self.ub - self.lb) < TOL)
return self._point

@property
def is_unbounded(self):
try:
return self._unbounded
except AttributeError:
self._unbounded = np.any(np.isinf(self.lb)) | np.any(np.isinf(self.ub))
return self._unbounded

# Due to the simplicity of this domain, we can use a more efficient sampling routine
def _sample(self, draw = 1):
if self.is_empty:
raise EmptyDomainException
x_sample = np.random.uniform(self.lb, self.ub, size = (draw, len(self)))
return x_sample

def _corner(self, p, **kwargs):
# Since the domain is a box, we can find the corners simply by looking at the sign of p
x = np.copy(self.lb)
I = (p>=0)
x[I] = self.ub[I]
if not self.isinside(x):
raise EmptyDomainException
return x

def _extent(self, x, p):
return self._extent_bounds(x, p)

def _isinside(self, X, tol = TOL):
return self._isinside_bounds(X, tol = tol)

def _normalized_domain(self, **kwargs):
names_norm = [name + ' (normalized)' for name in self.names]
return BoxDomain(lb = self.lb_norm, ub = self.ub_norm, names = names_norm)

@property
def A(self): return np.zeros((0,len(self)))

@property
def b(self): return np.zeros((0))

@property
def A_eq(self): return np.zeros((0,len(self)))

@property
def b_eq(self): return np.zeros((0))