def conduit_lengths(target,
throat_endpoints='throat.endpoints',
throat_length='throat.length',
throat_centroid='throat.centroid'):
r"""
Calculates conduit lengths. A conduit is defined as half pore + throat
+ half pore.
Parameters
----------
target : GenericGeometry
Geometry object which this model is associated with. This controls the
length of the calculated array, and also provides access to other
necessary properties.
throat_endpoints : str
Dictionary key of the throat endpoint values.
throat_diameter : str
Dictionary key of the throat length values.
throat_length : string (optional)
Dictionary key of the throat length values. If not given then the
direct distance bewteen the two throat end points is used.
Returns
-------
Dictionary containing conduit lengths, which can be accessed via the dict
keys 'pore1', 'pore2', and 'throat'.
"""
network = target.project.network
throats = network.map_throats(throats=target.Ts, origin=target)
cn = network['throat.conns'][throats]
# Get pore coordinates
C1 = network['pore.coords'][cn[:, 0]]
C2 = network['pore.coords'][cn[:, 1]]
# Get throat endpoints and length
EP1 = network[throat_endpoints + '.head'][throats]
EP2 = network[throat_endpoints + '.tail'][throats]
try:
# Look up throat length if given
Lt = network[throat_length][throats]
except KeyError:
# Calculate throat length otherwise based on piecewise model
Lt = piecewise(target, throat_endpoints, throat_centroid)
# Calculate conduit lengths for pore 1 and pore 2
L1 = _norm(C1 - EP1, axis=1)
L2 = _norm(C2 - EP2, axis=1)
Lt = _np.maximum(Lt, 1e-15)
return {'pore1': L1, 'throat': Lt, 'pore2': L2}
def ctc(target):
r"""
Calculates throat length assuming point-like pores, i.e. center-to-center
distance between pores. Also, this model assumes that pores and throat
centroids are colinear.
Parameters
----------
target : GenericGeometry
Geometry object which this model is associated with. This controls the
length of the calculated array, and also provides access to other
necessary properties.
Returns
-------
value : ndarray
Array containing throat length values.
"""
network = target.project.network
throats = network.throats(target.name)
cn = network['throat.conns'][throats]
C1 = network['pore.coords'][cn[:, 0]]
C2 = network['pore.coords'][cn[:, 1]]
value = _norm(C1 - C2, axis=1)
return value
def piecewise(target,
throat_endpoints='throat.endpoints',
throat_centroid='throat.centroid'):
r"""
Calculate throat length from end points and optionally a centroid
Parameters
----------
target : OpenPNM Object
The object which this model is associated with. This controls the
length of the calculated array, and also provides access to other
necessary properties.
throat_endpoints : string
Dictionary key of the throat endpoint values.
throat_centroid : string
Dictionary key of the throat centroid values, optional.
Returns
-------
Lt : ndarray
Array containing throat lengths for the given geometry.
Notes
-----
(1) By default, the model assumes that the centroids of pores and the
connecting throat in each conduit are colinear.
(2) If `throat_centroid` is passed, the model accounts for the extra
length. This could be useful for Voronoi or extracted networks.
"""
network = target.project.network
throats = network.map_throats(throats=target.Ts, origin=target)
# Get throat endpoints
EP1 = network[throat_endpoints + '.head'][throats]
EP2 = network[throat_endpoints + '.tail'][throats]
# Calculate throat length
Lt = _norm(EP1 - EP2, axis=1)
# Handle the case where pores & throat centroids are not colinear
try:
Ct = network[throat_centroid][throats]
Lt = _norm(Ct - EP1, axis=1) + _norm(Ct - EP2, axis=1)
except KeyError:
pass
return Lt
def norm(v, d=2):
return _norm(v, d)