Files
simpeg/code/utils.py
T
Rowan Cockett b33b04d9a6 Improved ndgrid, and pushed unused utilities to EldadsCode folder.
ndgrid returns vectors in a matrix by default, but input kwarg of vector=False, and you can return the matrices.
2013-07-10 17:41:50 -07:00

100 lines
2.4 KiB
Python

import numpy as np
def reshapeF(x, size):
return np.reshape(x, size, order='F')
def mkvc(x, numDims=1):
"""Creates a vector with the number of dimension specified
e.g.:
a = np.array([1, 2, 3])
mkvc(a, 1).shape
> (3, )
mkvc(a, 2).shape
> (3, 1)
mkvc(a, 3).shape
> (3, 1, 1)
"""
assert type(x) == np.ndarray, "Vector must be a numpy array"
if numDims == 1:
return x.flatten(order='F')
elif numDims == 2:
return x.flatten(order='F')[:, np.newaxis]
elif numDims == 3:
return x.flatten(order='F')[:, np.newaxis, np.newaxis]
def ndgrid(*args, **kwargs):
"""
Form tensorial grid for 1, 2, or 3 dimensions.
Returns as column vectors by default.
To return as matrix input:
ndgrid(..., vector=False)
The inputs can be a list or separate arguments.
e.g.
a = np.array([1, 2, 3])
b = np.array([1, 2])
XY = ndgrid(a, b)
> [[1 1]
[2 1]
[3 1]
[1 2]
[2 2]
[3 2]]
X, Y = ndgrid(a, b, vector=False)
> X = [[1 1]
[2 2]
[3 3]]
> Y = [[1 2]
[1 2]
[1 2]]
"""
# Read the keyword arguments, and only accept a vector=True/False
vector = kwargs.pop('vector', True)
assert type(vector) == bool, "'vector' keyword must be a bool"
assert len(kwargs) == 0, "Only 'vector' keyword accepted"
# you can either pass a list [x1, x2, x3] or each seperately
if type(args[0]) == list:
xin = args[0]
else:
xin = args
# Each vector needs to be a numpy array
assert np.all([type(x) == np.ndarray for x in xin]), "All vectors must be numpy arrays."
if len(xin) == 1:
return xin[0]
elif len(xin) == 2:
XY = np.broadcast_arrays(mkvc(xin[1], 1), mkvc(xin[0], 2))
if vector:
X2, X1 = [mkvc(x) for x in XY]
return np.c_[X1, X2]
else:
return XY[1], XY[0]
elif len(xin) == 3:
XYZ = np.broadcast_arrays(mkvc(xin[2], 1), mkvc(xin[1], 2), mkvc(xin[0], 3))
if vector:
X3, X2, X1 = [mkvc(x) for x in XYZ]
return np.c_[X1, X2, X3]
else:
return XYZ[2], XYZ[1], XYZ[0]