Multiwfn forum

i.s.ger

Member

Registered: 2020-12-01

Posts: 55

Patch: Feature: fractional calculus

Dear Tian Lu,

There is a patch for computing 2F2([a,b]; [c,d]; z) (generalized hypergeometric function) which is necessary for computing kernel of new derivatives.

Currently, it only setups internal parameters via 1000-26. Later, I will prepare a patch for computing new derivatives.

0001-Implement-all-things-for-fractional-calculus.patch.txt

Which iuserfunc can I use for new derivatives? I would prefer to have the same number for 1000-X menu and X iuserfunc, but 26 is busy.

Best regards,
Igor

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Patch: Feature: fractional calculus

Dear Igor,

Could you let me know what feature do you plan to add to Multiwfn? "kernel of new derivatives" makes me a bit confused.

Best,

Tian

i.s.ger

Member

Registered: 2020-12-01

Posts: 55

Re: Patch: Feature: fractional calculus

Dear Lian,

We almost finished the paper about the new feature based on fractional calculus. Hope, we will submit it soon.

Briefly, I found a way how to apply fractional calculus to the electron density for constructing new ingredients of DFT functionals. In fractional calculus, there are several ways how to compute derivatives with different kernels. And, I want to implement one of these derivatives in the mainline of Multiwfn as a reference implementation.

Best,
Igor

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Patch: Feature: fractional calculus

Dear Igor,

Great. I will merge your patch into official source code very soon and let you know details here.

Best,

Tian

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Patch: Feature: fractional calculus

Dear Igor,

I updated Multiwfn 3.8(dev) today and your patch has been applied. The Makefile has been slightly changed based on yours, and 2F2 files have been collectively put into "ext" subfolder of source code package, "ext" means "extension". You can put all files you developed in the future in this folder.

The 2F2 part of code will not be compiled for Windows version to avoid introducing dependency of C++ compiler, therefore preprocessor directives have been employed for two lines related to 2F2 in Multiwfn.f90.

Best,

Tian

i.s.ger

Member

Registered: 2020-12-01

Posts: 55

Re: Patch: Feature: fractional calculus

Dear Tian,

Thank you so much! And thank you for `ext` directory!

> The 2F2 part of code will not be compiled for Windows version to avoid introducing dependency of C++ compiler, therefore preprocessor directives have been employed for two lines related to 2F2 in Multiwfn.f90.

In the patch below, I dropped these #ifdef's and introduced ext/no2F2.f90 which has the save behavior like ext/no2F2.c. I hope it will reduce the number of #ifdef lines.
But the main part of the patch is related to the implementation of feature evaluation, which I inserted into function.f90. I chose iUserFunc 1303 (the same number now is for setting up fractional calculus in hidden Option 1000)

0001-Implement-evaluation-of-xi-alpha.patch.txt

Best regards,
Igor

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Patch: Feature: fractional calculus

Dear Igor,

I have updated Multiwfn 3.8(dev) today, your patch has been fully applied.

Best,

Tian

i.s.ger

Member

Registered: 2020-12-01

Posts: 55

Re: Patch: Feature: fractional calculus

Dear Tian,

Thank you so much!

It works nice!

Best regards,
Igor