From owner-chemistry "-at-" ccl.net Thu Jun 10 12:24:01 2021 From: "Phil Hasnip phil.hasnip~~york.ac.uk" To: CCL Subject: CCL: QM codes NOT written in Fortran Message-Id: <-54378-210610050846-25203-Ij7vAUrOGkHPmAxn/4C4yw^_^server.ccl.net> X-Original-From: Phil Hasnip Content-Type: multipart/alternative; boundary="0000000000009e20ae05c465bc94" Date: Thu, 10 Jun 2021 10:08:27 +0100 MIME-Version: 1.0 Sent to CCL by: Phil Hasnip [phil.hasnip^_^york.ac.uk] --0000000000009e20ae05c465bc94 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Dear J=C3=BCrgen, Thank you, I intended to write Python/C but clearly my brain did not communicate that to my fingers! I appreciate you correcting me. Not that you can't write a QM program entirely in Python, but the performance would be too poor to use in any research context. All the best, Phil ---------------------------------------------------------------------------= --------- Dr Phil Hasnip Email: phil.hasnip(_)york.ac.uk EPSRC RSE Fellow Web: www-users.york.ac.uk/~pjh503 Dept of Physics University of York Tel: +44 (0)1904 322225 York YO10 5DD On Thu, 10 Jun 2021 at 09:47, J=C3=BCrgen Gr=C3=A4fenstein jurgen.grafenste= in#%# chem.gu.se wrote: > Dear Phil, > > GPAW is actually written in a combination of C (for the hard-core part) > and Python (for the high-level layer). You can find more information here= : > > https://www.sciencedirect.com/science/article/pii/S1877050911000615 > > Best regards, > J=C3=BCrgen > > _____________________________________ > J=C3=BCrgen Gr=C3=A4fenstein > University of Gothenburg > Dept of Chemistry and Molecular Biology > SE-412 96 G=C3=B6teborg > Sweden > > jurgen.grafenstein(_)chem.gu.se > > On 10 Jun 2021, at 04:07, Phil Hasnip phil.hasnip[-]york.ac.uk < > owner-chemistry(_)ccl.net> wrote: > > Dear Joe, > > Yes there are, for example GPAW is written in Python. However, the choice > of many QM programs to use Fortran is not simply because they are "old" > codes, many newer QM packages have deliberately chosen Fortran over > alternatives (e.g. C++). QM simulations are computationally intensive, an= d > Fortran is rather hard to beat performance-wise -- though modern C++ > compilers are competitive these days (albeit with compiler development > teams an order of magnitude larger than the corresponding Fortran ones). > Fortran also has many modern features which are still lacking in most > mainstream languages, for example partitioned global-address space > (coarrays). > > I don't see much incentive to move the millions of lines of Fortran into > another language, but what is becoming increasingly common is to develop = a > high-level software layer in something else, usually Python, which allows > more rapid prototyping and development, whilst keeping all the > numerically-intensive work in Fortran or C++. > > I'm confused about your Mac M1 chipset reference; how does this relate to > your Fortran question? There are good ARM Fortran compilers, if that's wh= at > you're worried about. > > All the best, > > Phil Hasnip > > > -------------------------------------------------------------------------= ----------- > Dr Phil Hasnip Email: phil.hasnip**york.ac.uk > EPSRC RSE Fellow Web: www-users.york.ac.uk/~pjh503 > Dept of Physics > University of York Tel: +44 (0)1904 322225 > York YO10 5DD > > > On Thu, 10 Jun 2021 at 01:58, Joe Leonard jleonard42%x%gmail.com < > owner-chemistry**ccl.net> wrote: > >> Folks, are there QM packages that have managed to =E2=80=9Close=E2=80=9D= all their >> fortran code or are new enough to have been developed in a different >> language or different languages? I have not seen good comments re: the = Mac >> M1 chipset and I=E2=80=99m curious whether there are alternatives=E2=80= =A6 >> >> I=E2=80=99m sure others would be interested as well. >> >> Joe Leonard >> =E2=80=94 >> "Peter Thiel was right, we just can't build cool sh*t anymore. I really >> did want a flying car, and all I have is 140 characters and promises of = AI >> that never come true." >> >> > --0000000000009e20ae05c465bc94 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Dear=C2=A0J=C3=BCrgen,

Thank you, I int= ended to write Python/C but clearly my brain did not communicate that to my= fingers! I appreciate you correcting me. Not that you can't write a QM= program entirely in Python, but the performance would be too poor to use i= n any research context.

All the best,
Phil

------------------------------------------------------------------------= ------------
Dr Phil Hasnip =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 Email: phil.hasnip(_)york.ac.uk
EPSRC RSE Fellow=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Web:=C2=A0 www-users.york.ac.uk/~pjh503<= br>Dept of Physics
University of York =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 Tel: =C2=A0=C2=A0=C2=A0 +44 (0)1904 322225
York YO10 = 5DD


On Thu, 10 Jun 2021 at 09:47, J=C3= =BCrgen Gr=C3=A4fenstein jurgen.grafenstein#%#chem.gu.se <owner-chemis= try(_)ccl.net> wrote:
Dear Phil,

GPAW is actually written in a combination of C (for the hard-core part= ) and Python (for the high-level layer). You can find more information here= :


Best regards,
J=C3=BCrgen

_____________________________________
J=C3=BCrgen Gr=C3=A4fenstein
University of Gothenburg
Dept of Chemistry and Molecular Biology
SE-412 96 G=C3=B6teborg
Sweden

jurgen= .grafenstein(_)chem.gu.se

On 10 Jun 2021, at 04:07, Phil Hasnip phil.hasnip[-]york.ac.uk <owner-chemistry(_)ccl.net> wrote:
Dear Joe,

Yes there are, for example GPAW is written in Python. However, the cho= ice of many QM programs to use Fortran is not simply because they=C2=A0are = "old" codes, many newer QM packages have deliberately chosen Fort= ran over alternatives (e.g. C++). QM simulations are computationally intensive, and Fortran is rather hard to beat performa= nce-wise -- though modern C++ compilers are competitive these days (albeit = with compiler development teams an order of magnitude larger than the corre= sponding Fortran ones). Fortran also has many modern features which are still lacking in most mainstream l= anguages, for example partitioned global-address space (coarrays).=C2=A0

I don't see much incentive to move the millions of lines of Fortra= n into another language, but what is becoming increasingly common is to dev= elop a high-level software layer in something else, usually Python, which a= llows more rapid prototyping and development, whilst keeping all the numerically-intensive work in Fort= ran or C++.

I'm confused about your Mac M1 chipset reference; how does this relate = to your Fortran question? There are good ARM Fortran compilers, if that'= ;s what you're worried about.=C2=A0

All the best,

Phil Hasnip

----------------------------------------------------------------------= --------------
Dr Phil Hasnip =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 Email: phil.hasnip**york.ac.uk
EPSRC RSE Fellow=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Web:=C2=A0= www-users.york.ac.uk/~pjh503
Dept of Physics
University of York =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Tel:= =C2=A0=C2=A0=C2=A0 +44 (0)1904 322225
York YO10 5DD


On Thu, 10 Jun 2021 at 01:58, Joe Leo= nard jleonard42%x%gmail.com= <owne= r-chemistry**ccl.net> wrote:
Folks, are there QM packages that have managed to =E2=80=9Close=E2=80= =9D all their fortran code or are new enough to have been developed in a di= fferent language or different languages?=C2=A0 I have not seen good comment= s re: the Mac M1 chipset and I=E2=80=99m curious whether there are alternatives=E2= =80=A6

I=E2=80=99m sure others would be interested as well.

Joe Leonard
=E2=80=94
"Peter Thiel was right= , we just can't build=C2=A0cool sh*t anymore. I really did want a=C2=A0= flying car, and all I have is 140=C2=A0characters and promises of AI that n= ever=C2=A0come true."


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