>
>Rune Allnor skrev:
>> delechelle skrev:
>> > Hi
>> >
>> > I need to inverse a rather large matrix. Using 'inv'
>> > takes much time and I need to speed this up. What I actually have
>> > is the the follwing:
>> >
>> > B=V*D*V^{-1}
>>
>> What does B look like? If this is what one often occuring situation,
>> inverting V could be a lot cheaper than you could possibly imagine...
>
>> > Where V is an eigenvectors matrix, and D the eigenvalues diagonal
matrix,
>> > as
>
>> > [V,D]=eig(A) % in matlab
>
>Sorry. I meant to ask what A looks like.
>
>Rune
>
>
Hi,
A is a pentadiagonal matrix
Eric
Reply by Rune Allnor●October 13, 20062006-10-13
Rune Allnor skrev:
> delechelle skrev:
> > Hi
> >
> > I need to inverse a rather large matrix. Using 'inv'
> > takes much time and I need to speed this up. What I actually have
> > is the the follwing:
> >
> > B=V*D*V^{-1}
>
> What does B look like? If this is what one often occuring situation,
> inverting V could be a lot cheaper than you could possibly imagine...
> > Where V is an eigenvectors matrix, and D the eigenvalues diagonal matrix,
> > as
> > [V,D]=eig(A) % in matlab
Sorry. I meant to ask what A looks like.
Rune
Reply by Rune Allnor●October 13, 20062006-10-13
delechelle skrev:
> Hi
>
> I need to inverse a rather large matrix. Using 'inv'
> takes much time and I need to speed this up. What I actually have
> is the the follwing:
>
> B=V*D*V^{-1}
What does B look like? If this is what one often occuring situation,
inverting V could be a lot cheaper than you could possibly imagine...
Rune
Reply by ●October 12, 20062006-10-12
delechelle wrote:
> Hi
>
> I need to inverse a rather large matrix. Using 'inv'
> takes much time and I need to speed this up. What I actually have
> is the the follwing:
>
> B=V*D*V^{-1}
>
> Where V is an eigenvectors matrix, and D the eigenvalues diagonal matrix,
> as
>
> [V,D]=eig(A) % in matlab
I don't know if it is faster, but try the syntax described in 'help
slash'
John
Reply by delechelle●October 12, 20062006-10-12
Hi
I need to inverse a rather large matrix. Using 'inv'
takes much time and I need to speed this up. What I actually have
is the the follwing:
B=V*D*V^{-1}
Where V is an eigenvectors matrix, and D the eigenvalues diagonal matrix,
as
[V,D]=eig(A) % in matlab