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.
This commit is contained in:
Rowan Cockett
2013-07-10 17:41:50 -07:00
parent d4df6b4ce0
commit b33b04d9a6
2 changed files with 143 additions and 104 deletions
+87
View File
@@ -0,0 +1,87 @@
from numpy import *
import numpy as np
def diff(A, d):
if(d == 1):
return A[1:, :, :] - A[:-1, :, :]
elif(d == 2):
return A[:, 1:, :] - A[:, :-1, :]
else:
return A[:, :, 1:] - A[:, :, :-1]
#else:
# print('d must be 1,2 or 3')
def diffp(A, d1, d2):
if(d1 == 1 and d2 == 2):
return A[1:, 1:, :] - A[:-1, :-1, :]
elif(d1 == 1 and d2 == 3):
return A[1:, :, 1:] - A[:-1, :, :-1]
else:
return A[:, 1:, 1:] - A[:, :-1, :-1]
def diffm(A, d1, d2):
if(d1 == 3 and d2 == 2):
return A[:, :-1, 1:] - A[:, 1:, :-1]
elif(d1 == 1 and d2 == 3):
return A[1:, :, :-1] - A[:-1, :, 1:]
elif(d1 == 2 and d2 == 1):
return A[:-1, 1:, :] - A[1:, :-1, :]
else:
print('d must be 1, 2 or 3')
def ave(A, d):
if(d == 1):
return 0.5*(A[1:, :, :] + A[:-1, :, :])
elif(d == 2):
return 0.5*(A[:, 1:, :] + A[:, :-1, :])
elif(d == 3):
return 0.5*(A[:, :, 1:] + A[:, :, :-1])
else:
print('d must be 1,2 or 3')
def mkmat(x):
return reshape(matrix(x), (size(x), 1), 'F')
def hstack3(a, b, c):
a = mkvc(a)
b = mkvc(b)
c = mkvc(c)
a = mkmat(a)
b = mkmat(b)
c = mkmat(c)
return hstack((hstack((a, b)), c))
def ind2sub(shape, ind):
"""From the given shape, returns the subscrips of the given index"""
revshp = []
revshp.extend(shape)
mult = [1]
for i in range(0, len(revshp)-1):
mult.extend([mult[i]*revshp[i]])
mult = array(mult).reshape(len(mult))
sub = []
for i in range(0, len(shape)):
sub.extend([math.floor(ind / mult[i])])
ind = ind - (math.floor(ind/mult[i]) * mult[i])
return sub
def sub2ind(shape, subs):
"""From the given shape, returns the index of the given subscript"""
revshp = list(shape)
mult = [1]
for i in range(0, len(revshp)-1):
mult.extend([mult[i]*revshp[i]])
mult = array(mult).reshape(len(mult), 1)
idx = dot((subs), (mult))
return idx
+56 -104
View File
@@ -1,49 +1,6 @@
from numpy import *
import numpy as np
def diff(A, d):
if(d == 1):
return A[1:, :, :] - A[:-1, :, :]
elif(d == 2):
return A[:, 1:, :] - A[:, :-1, :]
else:
return A[:, :, 1:] - A[:, :, :-1]
#else:
# print('d must be 1,2 or 3')
def diffp(A, d1, d2):
if(d1 == 1 and d2 == 2):
return A[1:, 1:, :] - A[:-1, :-1, :]
elif(d1 == 1 and d2 == 3):
return A[1:, :, 1:] - A[:-1, :, :-1]
else:
return A[:, 1:, 1:] - A[:, :-1, :-1]
def diffm(A, d1, d2):
if(d1 == 3 and d2 == 2):
return A[:, :-1, 1:] - A[:, 1:, :-1]
elif(d1 == 1 and d2 == 3):
return A[1:, :, :-1] - A[:-1, :, 1:]
elif(d1 == 2 and d2 == 1):
return A[:-1, 1:, :] - A[1:, :-1, :]
else:
print('d must be 1, 2 or 3')
def ave(A, d):
if(d == 1):
return 0.5*(A[1:, :, :] + A[:-1, :, :])
elif(d == 2):
return 0.5*(A[:, 1:, :] + A[:, :-1, :])
elif(d == 3):
return 0.5*(A[:, :, 1:] + A[:, :, :-1])
else:
print('d must be 1,2 or 3')
def reshapeF(x, size):
return np.reshape(x, size, order='F')
@@ -53,7 +10,7 @@ def mkvc(x, numDims=1):
e.g.:
a = np.array(1,2,3)
a = np.array([1, 2, 3])
mkvc(a, 1).shape
> (3, )
@@ -75,8 +32,45 @@ def mkvc(x, numDims=1):
return x.flatten(order='F')[:, np.newaxis, np.newaxis]
def ndgrid(*args):
"""Form tensorial grid for 1, 2 and 3 dimensions. Return X1,X2,X3 arrays depending on the dimension"""
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:
@@ -84,64 +78,22 @@ def ndgrid(*args):
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
return xin[0]
elif len(xin) == 2:
X2, X1 = [mkvc(x) for x in np.broadcast_arrays(mkvc(xin[1], 1), mkvc(xin[0], 2))]
return np.c_[X1, X2]
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:
X3, X2, X1 = [mkvc(x) for x in np.broadcast_arrays(mkvc(xin[2], 1), mkvc(xin[1], 2), mkvc(xin[0], 3))]
return np.c_[X1, X2, X3]
def ind2sub(shape, ind):
# From the given shape, returns the subscrips of the given index
revshp = []
revshp.extend(shape)
mult = [1]
for i in range(0, len(revshp)-1):
mult.extend([mult[i]*revshp[i]])
mult = array(mult).reshape(len(mult))
sub = []
for i in range(0, len(shape)):
sub.extend([math.floor(ind / mult[i])])
ind = ind - (math.floor(ind/mult[i]) * mult[i])
return sub
def sub2ind(shape, subs):
# From the given shape, returns the index of the given subscript
revshp = list(shape)
mult = [1]
for i in range(0, len(revshp)-1):
mult.extend([mult[i]*revshp[i]])
mult = array(mult).reshape(len(mult), 1)
idx = dot((subs), (mult))
return idx
def mkmat(x):
return reshape(matrix(x), (size(x), 1), 'F')
def hstack3(a, b, c):
a = mkvc(a)
b = mkvc(b)
c = mkvc(c)
a = mkmat(a)
b = mkmat(b)
c = mkmat(c)
return hstack((hstack((a, b)), c))
if __name__ == '__main__':
X, Y, Z = mgrid[0:4, 0:5, 0:6]
print Z
t = ave(X, 1)
print t
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]