Re: [boost] different matrix library?

Subject: Re: [boost] different matrix library?
From: Edward Grace (ej.grace_at_[hidden])
Date: 2009-08-15 17:37:28

On 15 Aug 2009, at 21:58, joel wrote:

> Edward Grace wrote:
>> Yes.  By 'table -> vector/covector' do you mean in a similar  
>> manner to
>> 'reshape' in MATLAB? If so good.
> Yes. Your table has data that can be N-D, when you turn it into a
> vector, you do somethign akin to
> v = t(:) in matlab

Super.

>>
>>   P = 2*(identity(4) - outer_product(k,k)/inner_product(k,k));
>> [snip]
>>
> Ok, I'm maybe dense here, but, can you restate this like I was 4 yo ?
> What are the "redundant" parts ?

Maybe I'm being a little obscure, you get a symmetric matrix when  
it's evaluated. Let's just expand it out fully (for a length 3 real  
vector) v = <a,b,c> assuming that we ignore the inner product and the  
factor of 2 (scalars).



Note that the components above and below the diagonal are the same.   
In BLAS (or indeed boost::ublas) this would be a matrix of symmetric  
type (or Hermitian if complex).

>
>> Sounds good to me.  When's it finished? ;-)
> Dunno. I hope soon ;)

 From my humble experiences, thinking you've finished means you've  
only just about figured out what the problem actually is!

-ed