[petsc-users] Question about TaoLineSearchApply.

[Jason Sarich]

Hi Ce Qin,

What you are doing will work fine. There is no back-tracking in a
linesearch to a previously computed x, the last x computed is the current
solution.

Jason Sarich





On Sun, May 25, 2014 at 7:11 AM, Ce Qin <qince168 at gmail.com> wrote:

>  Hi Barry,
>
>  I think there is confusion about my question.
>
>  The purpose of line search is to find an \alpha_{k} that minimize f(x +
> \alpha p). This procedure usually choose several \alpha and returns a
> proper \alpha_{k}. For each \alpha, we need to compute the objective
> function and gradient of (x + \alpha p). In my FormFunctionGradient
> function, I save some internal data(model response) which will be printed
> in the monitor routine. If the objective function and gradient returned by
> TaoLineSearchApply isn't the latest computed,  my internal data becomes
> invalid in the monitor routine. My question is the order of the objective
> function and gradient corresponding to \alpha_{k} in this line search
> procedure.
>
>  If it is not clear, please let me know. Thanks.
>
>  Best regards,
> Ce Qin
>
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