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.
2026-06-29 03:04:53 +08:00 · 2013-07-10 17:41:50 -07:00
parent d4df6b4ce0
commit b33b04d9a6
2 changed files with 143 additions and 104 deletions
@@ -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