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RE: sum() behaving erratically?
From: |
Ciotti, Louis A |
Subject: |
RE: sum() behaving erratically? |
Date: |
Thu, 7 Oct 2004 08:37:40 -0400 |
Assuming that sum is suppose to behaive like matlab(according to matlab
documentation):
B = sum(A) returns sums along different dimensions of an array.
If A is a vector, sum(A) returns the sum of the elements.
If A is a matrix, sum(A) treats the columns of A as vectors, returning a
row vector of the sums of each column.
If A is a multidimensional array, sum(A) treats the values along the
first non-singleton dimension as vectors, returning an array of row
vectors.
B = sum(A,dim) sums along the dimension of A specified by scalar dim.
This leads me to believe that sum is working correctly.
-----Original Message-----
From: Henry F. Mollet [mailto:address@hidden
Sent: Wednesday, October 06, 2004 9:46 PM
To: address@hidden; Octave_post
Subject: Re: sum() behaving erratically?
I'm using Octave 2.1.46 and get the same results.
octave:9> help sum
sum is a built-in function
- Built-in Function: sum (X, DIM)
Sum of elements along dimension DIM. If DIM is omitted, it
defaults to 1 (column-wise sum).
Therefore I'd expect for a=[1,2];
that sum(a) should be the same as sum (a,1) = 1 2 and as stated below.
Henry
on 10/6/04 4:14 PM, address@hidden at address@hidden wrote:
> I'm a bit embarrassed to ask this, but here goes:
>
> If I let a=[1,2;3,4]; and then ask for sum(a), sum(a,1) and sum(a,2),
I
> get the answers
>
> 4 6 4 6 3
> 7
>
> respectively. Now I let a=[1,2]; and do the same. I now get
>
> 3 1 2 3
>
> indicating that in the second case sum(a) != sum(a,1), in direct
violation
> of the documentation in the manual. Is this supposed to be like this
and
> didn't I understand things, or is it a bug? (Octave is 2.1.57.)
>
>
> Kind regards,
> Maarten
>
>
>
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Octave is freely available under the terms of the GNU GPL.
Octave's home on the web: http://www.octave.org
How to fund new projects: http://www.octave.org/funding.html
Subscription information: http://www.octave.org/archive.html
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Octave is freely available under the terms of the GNU GPL.
Octave's home on the web: http://www.octave.org
How to fund new projects: http://www.octave.org/funding.html
Subscription information: http://www.octave.org/archive.html
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