[Users] Error Estimation for RK45CK

[Roland Haas]

Hello David,

MoL dynamically allocates and deallocates (since its use of
timelevels conflicts with Carpet's requirements for timelevels) storage
for ErrorEstimate in the the MoL_AllocateScratchSpace and
MoL_FreeScratchSpace schedule functions, which are both in
MoL_Evolution.

So the grid variable is not accessible outside of MoL_Evolution.

For debugging and if you know that there is e.g. only a few variable
with an error estimate you can comment out the MoL_FreeScratchSpace
block. A few here means "fewer than there are timelevels declared to
Carpet" since each variable is allocated a timelevel of ErrorEstimate
(and Carpet will abort the run if there are more timelevels in any grid
variable than it can handle).

Yours,
Roland

> Hello,
> 
> I am trying to read the MoL:ErrorEstimate outside of the StepSize.c
> routines.  For some reason it doesn’t work.  Is there something
> special that I need to do to get access to this GridFunction?
> 
> -DG
> 
> --
> David Garrison, Ph.D.
> Associate Dean for the College of Science and Engineering,
> Professor and Founding Chair of Physics
> University of Houston-Clear Lake
> Bayou 3611
> Houston, TX 77058
> 
> Phone: 281-283-3796
> https://urldefense.com/v3/__https://www.uhcl.edu/science-engineering/faculty/garrison-david__;!!DZ3fjg!55rKO2zffKCTddaTep4WnMwSLdzp1OiCJEfvBP1s-J2c79MnJwDQ_J87EbVvAT9whvuDYKysdl69ncMp6jU$ 
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> 
> "If we knew what it was we were doing, it would not be called
> research, would it?" — Albert Einstein.
> 
> 
> 
> 
> On Jul 26, 2023, at 3:10 PM, Erik Schnetter <schnetter at gmail.com>
> wrote:
> 
> David
> 
> This happens in the file "RK45.c" in line 252. The loop there accesses
> the "gamma_array" with the error estimation coefficients and then
> calls "MoL_LinearCombination" to estimate the error.
> 
> -erik
> 
> On Wed, Jul 26, 2023 at 3:02 PM Garrison, David
> <Garrison at uhcl.edu<mailto:Garrison at uhcl.edu>> wrote:
> 
> Hello,
> 
> Where in the MoL is the error estimates for RK45 calculated?  I can’t
> seem to find that in the source code.  Somehow they are written to
> the MOL::ERRORESTIMATE grid function but I can’t see where that is
> done.
> 
> -DG
> 
> --
> David Garrison, Ph.D.
> Associate Dean for the College of Science and Engineering,
> Professor and Founding Chair of Physics
> University of Houston-Clear Lake
> Bayou 3611
> Houston, TX 77058
> 
> Phone: 281-283-3796
> https://urldefense.com/v3/__https://www.uhcl.edu/science-engineering/faculty/garrison-david__;!!DZ3fjg!55rKO2zffKCTddaTep4WnMwSLdzp1OiCJEfvBP1s-J2c79MnJwDQ_J87EbVvAT9whvuDYKysdl69ncMp6jU$ 
> https://urldefense.com/v3/__http://www.uhcl.edu/physics__;!!DZ3fjg!55rKO2zffKCTddaTep4WnMwSLdzp1OiCJEfvBP1s-J2c79MnJwDQ_J87EbVvAT9whvuDYKysdl69e49iuXY$ 
> 
> "If we knew what it was we were doing, it would not be called
> research, would it?" — Albert Einstein.
> 
> 
> 
> 
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> 
> 
> --
> Erik Schnetter <schnetter at gmail.com<mailto:schnetter at gmail.com>>
> https://urldefense.com/v3/__http://www.perimeterinstitute.ca/personal/eschnetter/__;!!BCR0FSePrR4x!Em13k9KPwXveeqJOOqlFutrEYS-ZUde1eKk2-LVx-O4_SOfK0tMIjXjtuQk_d5z7g1NIZy5WdrRu-sGDzw$
> 



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