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Re: senseless warning in octave-3.6.2
From: |
Sergei Steshenko |
Subject: |
Re: senseless warning in octave-3.6.2 |
Date: |
Sun, 1 Jul 2012 17:20:31 -0700 (PDT) |
----- Original Message -----
> From: Ben Abbott <address@hidden>
> To: Sergei Steshenko <address@hidden>
> Cc: Jordi Gutiérrez Hermoso <address@hidden>; Octave users list
> <address@hidden>
> Sent: Monday, July 2, 2012 3:01 AM
> Subject: Re: senseless warning in octave-3.6.2
>
>
> On Jul 1, 2012, at 7:53 PM, Sergei Steshenko wrote:
>
>>
>>
>>
>>
>> ----- Original Message -----
>>> From: Jordi Gutiérrez Hermoso <address@hidden>
>>> To: Sergei Steshenko <address@hidden>
>>> Cc: c. <address@hidden>; Octave users list
> <address@hidden>
>>> Sent: Monday, July 2, 2012 12:01 AM
>>> Subject: Re: senseless warning in octave-3.6.2
>>>
>>> On 1 July 2012 16:42, Sergei Steshenko <address@hidden>
> wrote:
>>>> Why on earth two _vectors_ are promoted to a matrix ?
>>>
>>> http://www.gnu.org/software/octave/doc/interpreter/Broadcasting.html
>>>
>>> HTH,
>>> - Jordi G. H.
>>>
>>
>> No, the document does _not_ help. Because it does _not_ explain _why_ in a
> context of _only_ vector operands a matrix is produced (and, by the way, as I
> wrote, it's not "broadcasting", in programming WRT types
> "promotion" and "demotion" is used).
>>
>> As wrote much much earlier, essentially column vector vs row vector is a
> nuisance - one type of vector would suffice.
>>
>> IIUC, column vector is kind of default in Octave, that's why I expect
>>
>> vec = row_vec OP col_vec
>>
>> to be implemented as
>>
>> vec = row_vec(:) .OP col_vec(:)
>> .
>>
>> Regards,
>> Sergei.
>
> Strictly speaking there are no vectors or scalars. Only matrices.
>
> [1] -> is a 1x1 matrix
> [1;1] -> is a 2x1 matrix
> [1,2] -> is a 1x2 matrix
>
> This is a result of legacy Matlab code.
>
> Ben
Strictly speaking 2d matrices with one dimension equal to one are still vectors.
Strictly speaking row by column vector product is scalar vector product, i.e.
row_vec * col_vec
in Octave terms by _mathematical_ default should be implemented as
sum(row_vec(:) .* col_vec(:)), but it's not the default I want - in most of the
cases I really don't care whether a vector is a row or a column one, and I'm
wondering if anybody else cares.
I still don't understand the motive of promoting a N elements vector to N x N
elements matrix.
Regards,
Sergei.
>
- Re: senseless warning in octave-3.6.2, (continued)
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/01
- Re: senseless warning in octave-3.6.2, Francesco Potortì, 2012/07/01
- Re: senseless warning in octave-3.6.2, Mero, 2012/07/02
- Re: senseless warning in octave-3.6.2, Jordi Gutiérrez Hermoso, 2012/07/02
- Re: senseless warning in octave-3.6.2, Mero, 2012/07/02
- Re: senseless warning in octave-3.6.2, c., 2012/07/01
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/01
- Re: senseless warning in octave-3.6.2, Jordi Gutiérrez Hermoso, 2012/07/01
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/01
- Re: senseless warning in octave-3.6.2, Ben Abbott, 2012/07/01
- Re: senseless warning in octave-3.6.2,
Sergei Steshenko <=
- Re: senseless warning in octave-3.6.2, Michael Goffioul, 2012/07/02
- Re: senseless warning in octave-3.6.2, c., 2012/07/02
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/03
- Re: senseless warning in octave-3.6.2, Michael Goffioul, 2012/07/03
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/06
- Re: senseless warning in octave-3.6.2, Michael Goffioul, 2012/07/06
- Re: senseless warning in octave-3.6.2, c., 2012/07/06
- Re: senseless warning in octave-3.6.2, Nicholas Jankowski, 2012/07/03
- Re: senseless warning in octave-3.6.2, Jordi Gutiérrez Hermoso, 2012/07/03
- Re: senseless warning in octave-3.6.2, Sergei Steshenko, 2012/07/06