numpy/matlab compatibility

[Matt Funk]

Hi,

thank you Andrea. That is exactly what i was looking for. Great.
Andrea explained what the Matlab code does below. Sorry about the
confusion.
I was under the impression that numpy was leaning very heavily on Matlab
for its syntax and thus i assumed that
Matlab was mostly known for those using numpy.

Andrea:
you are right about the value 100. It should have been 0.5.
The original code has a different vector which is tested against 100. I
tried to simply reproduce the functionality with a random vector.
Thus the confusion.

Again, thanks for the input.
matt


On 1/25/2011 2:36 PM, Andrea Ambu wrote:
>
>
> On Tue, Jan 25, 2011 at 9:13 PM, Matt Funk <mafunk at nmsu.edu
> <mailto:mafunk at nmsu.edu>> wrote:
>
>     Hi,
>
>     i am fairly new to python. I was wondering of the following is do-able
>     in python:
>
>     1) a = rand(10,1)
>     2) Y = a
>     3) mask = Y > 100;
>     4) Y(mask) = 100;
>     5) a = a+Y
>
>
> No. Not like that. 
>
> You do literally:
> a = rand(10, 1)
> Y = a
> mask = Y>100
> Y = where(mask, 100, Y)
> a = a+Y
>
>
> More Pythonically:
> a = rand(10, 1)
> a = where(a > 100, a + 100, a + a)
>
>
> For those who don't speak Matlab:
>
> 1) a = rand(10,1) ; generates a 10x1 matrix for random number 0 < n < 1
> 2) Y = a 
> 3) mask = Y > 100; similar to: mask = [i>100 for i in Y]
> 4) Y(mask) = 100; sets to 100 elements of Y with index i for which
> mask[i] = True
> 5) a = a+Y ; sums the two matrices element by element (like you do in
> linear algebra) 
>
>
> Anyway... rand generates number from 0 up to 1 (both in python and
> matlab)... when are they > 100? 
>
>  
>
>     Basically i am getting stuck on line 4). I was wondering if it is
>     possible or not with python?
>     (The above is working matlab code)
>
>     thanks
>     matt
>     --
>     http://mail.python.org/mailman/listinfo/python-list
>
>

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