[petsc-dev] simplification of solvers that utilize KSPNASH STCG or GLTR

[Munson, Todd]

I will start making this simplification today in a new branch.

Todd.

> On Aug 22, 2016, at 6:18 AM, Munson, Todd <tmunson at mcs.anl.gov> wrote:
> 
> 
> We are in agreement.  I should not use double negatives.
> 
> This change should be made.
> 
> Todd.
> 
>> On Aug 21, 2016, at 11:39 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>> 
>>> On Aug 21, 2016, at 11:33 PM, Munson, Todd <tmunson at mcs.anl.gov> wrote:
>>> 
>>> 
>>> I don't see any reason not to make the change.
>> 
>>  I any new solvers are to be added in the future that utilize the KSPCGXXX solver functionality they would be easier and cleaner to implement.
>> 
>>  Barry
>> 
>>> 
>>> Todd.
>>> 
>>>> On Aug 21, 2016, at 9:40 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>>> 
>>>> 
>>>> Todd,
>>>> 
>>>> The TAO solvers that utilize KSPNASH STCG or GLTR have all this horribly redundant unneeded code 
>>>> 
>>>>   /* Solve the trust region subproblem */
>>>>   if (NTR_KSP_NASH == tr->ksp_type) {
>>>>     ierr = KSPNASHSetRadius(tao->ksp,tao->trust);CHKERRQ(ierr);
>>>>     ierr = KSPSolve(tao->ksp, tao->gradient, tao->stepdirection);CHKERRQ(ierr);
>>>>     ierr = KSPGetIterationNumber(tao->ksp,&its);CHKERRQ(ierr);
>>>>     tao->ksp_its+=its;
>>>>     tao->ksp_tot_its+=its;
>>>>     ierr = KSPNASHGetNormD(tao->ksp, &norm_d);CHKERRQ(ierr);
>>>>   } else if (NTR_KSP_STCG == tr->ksp_type) {
>>>>     ierr = KSPSTCGSetRadius(tao->ksp,tao->trust);CHKERRQ(ierr);
>>>>     ierr = KSPSolve(tao->ksp, tao->gradient, tao->stepdirection);CHKERRQ(ierr);
>>>>     ierr = KSPGetIterationNumber(tao->ksp,&its);CHKERRQ(ierr);
>>>>     tao->ksp_its+=its;
>>>>     tao->ksp_tot_its+=its;
>>>>     ierr = KSPSTCGGetNormD(tao->ksp, &norm_d);CHKERRQ(ierr);
>>>>   } else { /* NTR_KSP_GLTR */
>>>>     ierr = KSPGLTRSetRadius(tao->ksp,tao->trust);CHKERRQ(ierr);
>>>>     ierr = KSPSolve(tao->ksp, tao->gradient, tao->stepdirection);CHKERRQ(ierr);
>>>>     ierr = KSPGetIterationNumber(tao->ksp,&its);CHKERRQ(ierr);
>>>>     tao->ksp_its+=its;
>>>>     tao->ksp_tot_its+=its;
>>>>     ierr = KSPGLTRGetNormD(tao->ksp, &norm_d);CHKERRQ(ierr);
>>>>   }
>>>> 
>>>> This can be simplified a great deal by making the names 
>>>> 
>>>> KSPCGSetRadius(), KSPGGGetNormD() etc you only need to change the registration from 
>>>> 
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPNASHSetRadius_C",KSPNASHSetRadius_NASH);CHKERRQ(ierr);
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPNASHGetNormD_C",KSPNASHGetNormD_NASH);CHKERRQ(ierr);
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPNASHGetObjFcn_C",KSPNASHGetObjFcn_NASH);CHKERRQ(ierr);
>>>> 
>>>> to 
>>>> 
>>>> 
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPCGSetRadius_C",KSPCGSetRadius_NASH);CHKERRQ(ierr);
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPCGGetNormD_C",KSPCGGetNormD_NASH);CHKERRQ(ierr);
>>>> ierr = PetscObjectComposeFunction((PetscObject)ksp,"KSPCGGetObjFcn_C",KSPCGGetObjFcn_NASH);CHKERRQ(ierr);
>>>> 
>>>> Is there any reason we shouldn't do this? Essentially these three KSPs are a special subclass of KSPCG that supports these additional methods.  Anything specific to an individual one like the Lanczo stuff still remains with it.
>>>> 
>>>> Barry
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>> 
>