Add relative error check in adaptive time stepping algorithm for rk23…

[xfong]

…, rk45dp and rk56 time steppers

[godsic]

@xfong

First of all, that you very much for the effort and for sharing this one with us.

Could you please

• elaborate a bit on motivation for using relative error control;
• provide some example .mx3 scripts where it helps overcome absolute error control limitations;
• comment on what to expect performance- and precision-wise.

[xfong]

• The adaptive time steeping control will benefit in cases where absolute errors of 1e-5 are much smaller than relTol * value of interest. This can help the transient simulation use larger time steps and hasten the completion of simulations.
• The fixes are directly compatible with the existing .mx3 files with no modifications needed. The limitations on my side are that I do not have the tools to perform the benchmarking that you want and I suggest you can check the differences in runtimes on your set up. Also, it is more likely that the changes will benefit simulations that typically run for a long time.
• At least 5% faster transient simulations are expected for simulations that typically take 30 minutes or longer to complete

Best,

Xuanyao (Kelvin) FONG

Assistant Professor

Department of Electrical & Computer Engineering, Faculty of Engineering

National University of Singapore

4 Engineering Drive 3

Singapore 117583

Office E4-05-23

Phone: +65-6516-6658

Fax: +65-6779-1103

Email: [email protected]

From: Mykola Dvornik [email protected] Sent: Wednesday, November 18, 2020 4:17 PM To: mumax/3 [email protected] Cc: xfong [email protected]; Mention [email protected] Subject: Re: [mumax/3] Add relative error check in adaptive time stepping algorithm for rk23… (#275)

@xfong https://github.com/xfong

First of all, that you very much for the effort and for sharing this one with us.

Could you please

• elaborate a bit on motivation for using relative error control;
• provide some example .mx3 scripts where it helps overcome absolute error control limitations;
• comment on what to expect performance- and precision-wise.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/mumax/3/pull/275#issuecomment-729515017 , or unsubscribe https://github.com/notifications/unsubscribe-auth/ABRJYBLAY6QZBUSXPSDH5KLSQN7ITANCNFSM4TZTMT2Q . https://github.com/notifications/beacon/ABRJYBK5RPQ75RKOULPLMZTSQN7ITA5CNFSM4TZTMT22YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOFN5YICI.gif

[godsic]

@xfong

• please be prepared for a long review process as this pull request touches very sensitive part of mumax3;
• please restructure your code in a way, that using RelErr = 0 exactly follows the current code, while RelErr > 0 triggers your modifications.

[xfong]

I need to update the code in the branch to meet your requirements.

Best,

Xuanyao (Kelvin) FONG

Assistant Professor

Department of Electrical & Computer Engineering, Faculty of Engineering

National University of Singapore

4 Engineering Drive 3

Singapore 117583

Office E4-05-23

Phone: +65-6516-6658

Fax: +65-6779-1103

Email: [email protected]

From: Mykola Dvornik [email protected] Sent: Wednesday, November 18, 2020 6:26 PM To: mumax/3 [email protected] Cc: xfong [email protected]; Mention [email protected] Subject: Re: [mumax/3] Add relative error check in adaptive time stepping algorithm for rk23… (#275)

@xfong https://github.com/xfong

• please be prepared for a long review process as this pull request touches very sensitive part of mumax3;
• please restructure your code in a way, that using RelErr = 0 exactly follows the current code, while RelErr > 0 triggers your modifications.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/mumax/3/pull/275#issuecomment-729584236 , or unsubscribe https://github.com/notifications/unsubscribe-auth/ABRJYBPOI32GU5HSNCNSHNLSQOOJ5ANCNFSM4TZTMT2Q . https://github.com/notifications/beacon/ABRJYBNKQYRHSXPXMVBZ7IDSQOOJ5A5CNFSM4TZTMT22YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOFN6JE3A.gif