[petsc-dev] Solving under determined systems

Mark Adams mfadams at lbl.gov
Wed Sep 21 20:24:53 CDT 2016


I thought least squares was for tall skinny (overdetermined) solves? I have
a short fat (5 x ~100) matrix to solve.

On Wed, Sep 21, 2016 at 4:24 PM, Stefano Zampini <stefano.zampini at gmail.com>
wrote:

> Mark,
>
> You can use KSPLSQR
>
> Stefano
>
> Il 21 set 2016 11:21 PM, "Mark Adams" <mfadams at lbl.gov> ha scritto:
>
>> I want to solve for w in V' w = b, where V is tall and skinny. So a short
>> fat matrix "solve". This is underdetermined. I would like to minimize the
>> two norm (or any norm) of w. This looks like an optimization problem, would
>> TAO do this?
>> Mark
>>
>
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