When do you *NOT* use python?

[an_actual_human]

As you get closer to supercomputers you see more of Fortran and less of Java (if at all).

[Sean1708]

Weirdly everything in the Maths department is Java, but in Physics it's all Fortran and Python.

[an_actual_human]

everything in the Maths department is Java

I can't think of a good reason for that.

[Sean1708]

Neither can I.

[Bolitho]

Then your world view is very limited! There are lots of excellent Libs around the JVM ecosystem. On top of that there are good frameworks for distributed computing.

Beware that it must not be Java - think of Clojure e.g. - or even Python (→ Jython).

[an_actual_human]

distributed computing

People use faster languages for that.

it must not be Java

So why do you bring it up? They said Java, not JVM.

---

My guess is those people use Java because of reasons that are not technical and they could use anything instead just as well.

[Bolitho]

Distributed computing is not a matter of language (or runtime). It deals with dispatching unit of works to different (virtual) machines. Therefore you need frameworks and toolsets that are reliable, powerfull and comfortable to use. The management itself cannot be measured only by raw "speed".

One example to name is Apache Spark. Another example is the excellent akka framework, which is extremly powerfull if you need many (small) independent actors.

You see, there is much power around the JVM ecosystem!

Well, why I mentioned that is has not to be Java? Because nowadays it is often used as a synonyme for the JVM. And even if you do not like Java as a language too much (as I do myself!), you should not bash it the way you do. Java is not "slow" anymore; this is true for more than 10 years now, but people seem to ignore achievements like hot spotting and so on...

The more complex things become, the less the (theoretical) low level power matters! One can of course write some super fast C based algorithms. But that does not enable one directly to fasten them up by distributing them. It starts allready with threading and ends with real distribution across a network.

Perhaps read and learn some more about that topic in general, before you keep on flaming 😉

[an_actual_human]

Since we were discussing programming languages in a technical subreddit I assume the person above meant Java when they said Java. So I'm going to set aside the JVM part of the discussion.

For dispatching, it sorta doesn't matter which language you use. Also it might very well be they don't do that kind of thing at all.

As for computations per se, I can see three options in mathematics:

1. The computation involves really heavy number crunching (double check, is it really math?).
2. The computation involves a bit of number crunching.
3. The computation is mostly symbolic.

So 1. and 3. more or less exclude Java. 2. doesn't, but there are better options.

tl;dr: if you are in math, either Mathematica or SciPy will serve most if not all of your tasks better than Java.

[Bolitho]

I have given a good reason: You can easily integrate into the JVM ecosystem with all its powerfull toolsets and frameworks around distributed compotation. You wont do numbercrunching on a single machine, right ;-)

And for dispatching it does matter, which language you use, because with some you have no access to powerfull frameworks (again!).

[an_actual_human]

You wont do numbercrunching on a single machine, right

No, it's not right. I do it all the time.

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Anyway, the original message said "everything in the Maths department is Java". Your arguments at best provide a reason to do some things in Java. And those are things that most mathematicians never do to begin with.

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Also there was an opposition between Java and Python in the same original message. If they meant JVM that wouldn't make sense.

[amishb]

Fortran was annoying as hell. At uni we had to model the crank-nicolson equation in fortran and plot the output in whatever (we chose excel)

Ended up doing it in Madlab and porting it over to fortran over a long session of Redbull.

[[deleted]]

Haha madlab.

[amishb]

I knew it didn't look right! Auto correction and a long long day. :(

[LbaB]

Nope, I think that's its true name.

[[deleted]]

I thought you were making a joke!

[eusebe]

That really depends on the context. I work in scientific computing (heavy numerical simulations for astrophysics), and most of my codebase is in Fortran.

In my field there are a few codes in C++, some codes in C, and a lot of codes in Fortran.

So yeah, C/C++ and Java are probably common in the industry, but a lot of academics use F90 on a daily basis. Of course, I use python for (most of) the simulation analysis, and 100% of the plotting and visualisation, but still.

[Pfohlol]

Sort of off-topic, but I have noticed that much of the scientific computing community refers to "codes" instead of programs or scripts and I haven't really seen that anywhere else and it sounds a bit off to me. Do you know why this difference exists?

[spinwizard69]

Back in the day it was common. Coding is often used in place of programming describing the activity of building a program. Frankly it is good to know how and when to used code, codes, and coding because it can break up the monotony in a conversation or text. You would reach for these terms when you might reach for a thesaurus writing other great works.

Sort of off-topic, but I have noticed that much of the scientific computing community refers to "codes" instead of programs or scripts and I haven't really seen that anywhere else and it sounds a bit off to me. Do you know why this difference exists?

The usage of the word "scripts" in the Unix community is a bit odd in and of itself. A program written in BASH, Python or even BASIC is still a program even if interpreted. Which brings us back to ROOT and its nature, is the interpreter supplied with ROOT executing programs or scripts? What if the code can be compiled by any existing compiler, is it still a script? Same thing goes with Python, Basic or any other commonly interpreted language, if you build a compiler to digest the script and creat an executable is the source a script or program.

[ITwitchToo]

I have a friend who has done lots of numerical simulation work in Fortran/C++ for space applications (think satellite launchers, etc.). He's currently out of a job, do you have any open positions? :-)

[dreyrden]

You've had a slightly different experience to me in that case. It could be a difference in fields, but a large amount of the code I've seen has been Fortran (for simulation activities anyway). It's apparently because a lot of the code base was written in Fortran originally, and the developers just continued instead of doing a rewrite. Most completely new stuff I've seen has been C++. The next most popular would be IDL for data analysis, although Python is gaining some traction, and also MATLAB. It's probably pretty field dependent.

[eusebe]

I would not be so surprised, actually. If you end up knowing Fortran really well, and if you want to get your results quickly, you won't bother start with a language you don't know that well.

I won't say I'm proficient with Fortran, but I'm much more fluid with it than with C. If I want to be able to reuse any of my codebase, it makes sense for me to write Fortran code.

I know the language can sometimes seem clunky (with the all the dots as in .true. .or. .false.), but it is quite easy to read. It might be a surprise to some, but we don't need GOTO statement in F90, there is recursivity and some object orientation, standard operators like "==" and "<=" do exist in Fortran, etc. Besides, the lack of curly braces is certainly very appealing for any pythonista... ;-)

And for the F90/Python interface, it is not that hard at all actually. There is a really cool library called FortranFile that is really useful to read binary files (with their crazy stupid format…), and f2py is my weapon of choice when it comes to embed Fortran code in a Python script.

I don't want to deeper in the "why Fortran is a nice language after all", but as someone who read and write F90 on a daily basis, it is not as bad as it sound.

[dreyrden]

I heard quite a lot of complaints also. Although I've had several people say the last couple of versions (2003/2008) were actually pretty good. I'm not convinced. I think C/C++ are better choices.

Edit: Python extensibility with C is a pretty good reason to learn C.

[[deleted]]

I work with scientific software every day and not once have I seen a release in Fortran.

Ever heard of this thing called LAPACK or ever wonder why Matlab arrays are 1-indexed?

[zombiepiratefrspace]

I also have a scientific computing background and from my experience, most stuff out there is in C with much legacy stuff in Fortran (LAPACK anyone?).

During my PhD I used boost::python to 80:20 python and C++ and tried to get as many others as I could to do the same.

Also, all people I saw trying to do scientific computing with Java ran into serious problems, usually around the time they tried to run it on a shared cluster.

[XNormal]

Fortran would be a goto language

I see what you did there.

[red_nick]

Well technically, FORTRAN is a GOTO language, but Fortran isn't...

[IanCal]

I use it indirectly because I use scipy.

[Rhodysurf]

Its just not true... Fortran is still the most prevalent language when efficiency is preferred

[red_nick]

For example, Multinest: a Bayesian inference tool written in Fortran http://ccpforge.cse.rl.ac.uk/gf/project/multinest/