[Numpy-discussion] Matrix element assignment

Blair Hall b.hall at irl.cri.nz
Sun Mar 16 15:26:16 CST 2003


I have upgraded from NumPy 21 to NumPy 23 and am
surprised to find that my matrix assignment doesn't work like it used to.

For example:

 >>> from Matrix import *
 >>> m = Matrix( [[1,2],[3,4]])
 >>> m[1,1]
4
 >>> m[1,1] = 2
Traceback (most recent call last):
File "<interactive input>", line 1, in ?
File "C:\PYTHON22\lib\site-packages\Numeric\Matrix.py", line 183, in
__setitem__
value = value[0,0]
IndexError: invalid index
 >>>

Apparently, I should have written
 >>> m[1,1] = Matrix( 2 )

Is this really indended, or am I confused?

The change appears to have been introduced
to NumPy in release 21.3

I note that similar code using an array does work:

 >>> from Numeric import *
 >>> m = array( [[1,2],[3,4]])
 >>> m[1,1]
4
 >>> m[1,1] = 3
 >>> m[1,1]
3






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