Numpy linalg - Revision history

Bugman: Added the Category:Development category.

2015-11-06T17:07:02Z

2015-10-15T14:17:27Z

Forced creation of a TOC - this will improve the formatting on the main page 'Did you know...' section.

2014-06-25T17:26:43Z

Stride stride through outer matrix

2014-06-25T14:41:07Z

Stride stride through outer matrix

2014-06-25T13:53:06Z

Stride tricks

2014-06-25T09:22:12Z

Stride tricks

2014-06-22T23:51:42Z

Stride tricks

2014-06-21T09:58:58Z

Stride tricks

2014-06-21T09:48:45Z

Stride tricks

2014-06-20T20:15:34Z

Ellipsis broadcasting in numpy.einsum

← Older revision		Revision as of 14:17, 15 October 2015
Line 1:		Line 1:
		+	__TOC__
		+
	== How to transpose higher dimension arrays ==		== How to transpose higher dimension arrays ==
	http://jameshensman.wordpress.com/2010/06/14/multiple-matrix-multiplication-in-numpy/		http://jameshensman.wordpress.com/2010/06/14/multiple-matrix-multiplication-in-numpy/

@@ Line 266: / Line 266: @@
      # bytes_between_elements
-     bbe = 1 * power_itz
+     bbe = ND * power_itz
      # bytes between row. The distance in bytes to next row is number of Columns elements multiplied with itemsize. NE * NS * NM * NO
-     bbr = ND * power_itz
+     bbr = 1 * power_itz
-     cut_strides = tuple([bbe, bbr])
+     cut_strides = tuple([bbr, bbe])
-     print cut_strides
+     print "cut_strides", cut_strides
      print power_arr
@@ Line 285: / Line 285: @@
      # Zip them together and iterate
      i = 0
      for mat_i, pow_i in zip(mat_view, power_view):
          mat_power_view_i = matrix_power(mat_i, int(pow_i))
 # Execute main function.
 if __name__ == "__main__":
      main()
 </source>

@@ Line 148: / Line 148: @@
 <source lang="python">
 from numpy.lib.stride_tricks import as_strided
-import numpy as np
+from numpy import arange, asarray, int16, zeros
-NE, NS, NM, NO, ND, Row, Col = 1, 2, 2, 1, 2, 2, 2
+mat = arange(NE*NS*NM*NO*ND*Row*Col).reshape(NE, NS, NM, NO, ND, Row, Col)
+power_arr = zeros([NE, NS, NM, NO, ND])
 print "mat is:"
 for ei in range(NE):
      for si in range(NS):
@@ Line 160: / Line 176: @@
              for oi in range(NO):
                  for di in range(ND):
-                     print("ei:%i, si:%i, mi:%i, oi:%i, di:%i"%(ei, si, mi, oi, di))
+                    power_i = power_arr[ei, si, mi, oi, di]
-                     print(mat[ei, si, mi, oi, di])
+                     print("ei:%i, si:%i, mi:%i, oi:%i, di:%i, power:%i"%(ei, si, mi, oi, di, power_i))
+                     mat_i = mat[ei, si, mi, oi, di]
-size = mat.itemsize
+                    #print mat_i
-print "itemsize is:"
-print size
+                    mat_power_i = matrix_power(mat_i, power_i)
-strides = mat.strides
+a = zeros([10, 2, 2, 2])
-print "strides is"
+print a
-print strides
+print a.itemsize
 </source>

← Older revision		Revision as of 23:51, 22 June 2014
Line 106:		Line 106:

	http://wiki.scipy.org/Cookbook/SegmentAxis		http://wiki.scipy.org/Cookbook/SegmentAxis
		+
		+	http://scipy-lectures.github.io/advanced/advanced_numpy/

	Simple, with window 3		Simple, with window 3

@@ Line 112: / Line 112: @@
 x=np.arange(row*col).reshape((row, col))
 print x
@@ Line 117: / Line 118: @@
 # Shape should end out in tuple.
 shape = tuple([row, col - window + 1,  window])
-print "shape is:", shape
+print "stride shape is:", shape
 # Get strides
@@ Line 127: / Line 128: @@
 print "itemsize is", x_str
-# Again, strides should be in tuple
+# Again, strides should be in tuple.
 cut_strides = tuple(list(x_str) + [x_itz])
 print "cut strides are", cut_strides
 y = as_strided(x, shape=shape, strides=cut_strides)
 </source>
@@ Line 139: / Line 147: @@
 from numpy.lib.stride_tricks import as_strided
 import numpy as np
-−
 NE, NS, NM, NO, ND, Row, Col = 1, 2, 2, 1, 2, 2, 2
-−
-mat = np.arange(1,NE*NS*NM*NO*ND*Row*Col+1).reshape(NE, NS, NM, NO, ND, Row, Col)
+mat = np.arange(NE*NS*NM*NO*ND*Row*Col).reshape(NE, NS, NM, NO, ND, Row, Col)
 print "mat is:"
-sz = mat.itemsize
+for ei in range(NE):
 print "itemsize is:"
-print sz
+print size
 print "strides is"
-print mat.strides
+print strides
 </source>

← Older revision		Revision as of 09:48, 21 June 2014
Line 107:		Line 107:
	http://wiki.scipy.org/Cookbook/SegmentAxis		http://wiki.scipy.org/Cookbook/SegmentAxis

		+	Simple, with window 3
		+	<source lang="python">
		+	row, col = 3, 5
		+
		+	x=np.arange(row*col).reshape((row, col))
		+	print x
		+
		+	window = 3
		+	# Shape should end out in tuple.
		+	shape = tuple([row, col - window + 1, window])
		+	print "shape is:", shape
		+
		+	# Get strides
		+	x_str = x.strides
		+	print "strides is", x_str
		+
		+	# Get itemsize, Length of one array element in bytes. Depends on dtype. float64=8, complex128=16.
		+	x_itz = x.itemsize
		+	print "itemsize is", x_str
		+
		+	# Again, strides should be in tuple
		+	cut_strides = tuple(list(x_str) + [x_itz])
		+	print "cut strides are", cut_strides
		+
		+	y = as_strided(x, shape=shape, strides=cut_strides)
		+	</source>
		+
		+	And then

	<source lang="python">		<source lang="python">

@@ Line 88: / Line 88: @@
 a3_e =  np.einsum(a3, [Ellipsis, 0, 1], a3, [Ellipsis, 1, 2])
 print a3_e
 </source>