how to resolve linear equations of system

[enjoywm at cs.wm.edu]

Thank you very much!
>
> On Jun 25, 2008, at 4:29 PM, enjoywm at cs.wm.edu wrote:
>
>> Hi,
>> I have a linear equations of system such as Kx=u.
>> 1. If K is singular, can I use KSPSolve to solve it?
>
>     If you know the null space of K you may be able to use the PETSc
> iterative solvers.
> If K is rectangular then likely you would not benefit from using PETSc
>
> If your linear systems are sparse and less than 50 to 100,000 unknowns
> then I recommend
> using Matlab for your computations. The learning curve for PETSc means
> it
> is reserved for problems so large that simpler techniques/packages do
> not work.
>
>>
>> 2. If K is non-singular I also can use x= inverse(K)u to do it.
>
>     Suggest you read a good book on Iterative methods for linear
> systems like
> by Saad.
>
>    Barry
>
>
>>
>> Which one is better?
>>
>> Best,
>> Yixun
>>
>
>