Try Julia

by bsg75 • 12 years ago

108 103 12 years ago

sdegutis7• 12 years ago

Not seeing a prompt. It might be because of the internal "POST http://forio.com/julia/repl/sessions 503 (Service Unavailable)" error?

boyers• 12 years ago

Probably got "slashdotted".

stuinzuri7• 12 years ago

Yes, we've been slammed. We are shrinking the timeout and bring up more servers. But our capacity is not unlimited. Folks might have to come back later.

stuinzuri7• 12 years ago

OK, we've added more servers of larger instance types! You should be good now.

tbarbugli• 12 years ago

a big white page is not really the best introduction ever (or am i missing the point/humor?)

bsg75• 12 years ago

It was working, until I submitted it here. Maybe too many people Trying Julia.

stuinzuri7• 12 years ago

Yup, we've been properly slashdotted. Attempting to bring up more servers and shrinking session timeout. But...

stuinzuri7• 12 years ago

All fixed now. We have added more servers of larger instance types to support the Julia RELP.

jonhmchan• 12 years ago

Doesn't seem to work - would love to find a great resource on Julia

sdegutis7• 12 years ago

I've found the docs[1] to be extremely easy to follow, as a nice blend between a tutorial and a spec.

[1] http://docs.julialang.org/en/latest/manual/

stuinzuri7• 12 years ago

Try again, please. We spun up more and larger instances to handle the interest from HN.

mlubin• 12 years ago

koding.com is another way to get an interactive REPL online: https://koding.com/Julia

jnazario• 12 years ago

oh awesome resource, thanks for the link! (looks down from overuse right now but still, cool!)

julia++, i started playing with it this weekend and i'm super pleased. i concur with another comment in this discussion that this is what i wish python had been evolving into. it gets me wondering if python is maybe being left behind compared to other dynamic languages or if it's just fad-ism at work (or me just learning more about languages and features).

Blahah• 12 years ago

It's really easy to try Julia by just downloading it: http://julialang.org/downloads/.

I'm becoming increasingly convinced that Julia is the future of technical computing. We've just started pulling together a BioJulia team - if anyone is interested drop an email (in profile).

vezzy-fnord• 12 years ago

Any reasoning behind such a generically bold statement?

TheTurd• 12 years ago

Any reasoning behind such a generically bold statement?

If and when they're right, they can smugly point out how forward thinking they were.

RivieraKid15• 12 years ago

- Good performance

- Lisp-like macros and other metaprogramming facilities

- It's a general purpose language

- Multiple dispatch

- Designed for parallelism and distributed computation

sdegutis7• 12 years ago

Honestly I'm convinced it's a lot more generally applicable than scientific computing. Much of heavy lifting I had to do in C, I can now do in Julia with nearly the same speed and efficiency. Plus, for a lot of the problems I would have chosen Python, Ruby, or even Clojure for, I could really see myself using Julia now.

orangecat• 12 years ago

Same here. In my so-far limited experience, it feels like the upgrade to Python 2 that I wish Python 3 had been.

RivieraKid15• 12 years ago

+1 Besides libs and ecosystem in general, I don't see any advantage Python / Ruby / Clojure have over Julia.

sdegutis7• 12 years ago

I can see Julia replacing Go for a lot of people, specifically those who came from a Python or Ruby background and are using Go for the kind of things more typically written in those languages. I bet Julia will shine in this problem space.

forkandwait• 12 years ago

Can julia yet do the equivalent of the following Octave code:

proportion_value = x ./ sum(x)

The blocker for me with julia is translating my vectorized way of thinking into loops. I know the loops are optimized, but yuck.

RivieraKid15• 12 years ago

Yes, this works in Julia without any changes.

LinaLauneBaer• 12 years ago

Adblock on Chrome is blocking the command prompt by default. At least on my system...

williamstein• 12 years ago

You can also try Julia in your browser here: https://cloud.sagemath.com However, you have to (1) make a free account, (2) create a project, (3) open project, click on "+New", click Terminal, (4) type "julia". If you create a .jl file instead of a Terminal (at +New), you'll have proper Julia syntax highlighting and indentation; you can then run that file from the terminal... (Disclaimer: I'm the founder of SageMathCloud.)

NicoJuicy• 12 years ago

You could have had more users if your url was:

https://cloud.sagemath.com/new/jl ;-)

kartikkumar2• 12 years ago

I've been struggling with building a C++ library for astrodynamics simulations (anything involving the motion of objects in space) within my research group for the last four year. The biggest problem is that for our applications, performance-wise a lot of high-level languages just don't cut it (particularly MATLAB, which is pushed down our throat from freshman year onwards). After some deliberation (and before Python really caught my eye) I opted for C++. That unfortunately brings with it an incredibly steep learning curve for new students who typically aren't interested in programming, but just want to get to the fun space mission analysis stuff. As a result, the project has grown a lot, but interest is waning. Julia seems like the ideal blend between high-level and high-performance.

As a general question, is Julia Studio the best way to go about setting up a workflow? Or should I go with something like a Julia plugin for Sublime Text (which I believe exists). Or are there any other tools out there that make Julia dev straightforward?

ihnorton6• 12 years ago

Regarding workflow, the best option is IJulia (https://github.com/JuliaLang/IJulia.jl) which has nice integration with plotting and useful things like LaTeX. Vi and Emacs are well-supported, and I know the Sublime tools have gotten a lot of attention from several people.

Not directly related to performance, but you might be interested in this: https://github.com/helgee/JPLEphemeris.jl

kartikkumar2• 12 years ago

Very cool, thanks for the tips!

That JPL Ephemeris library has given me an idea. I think I might try porting over the NAIF Spice [1] toolkit to Julia. It has MATLAB, IDL, C and FORTRAN ports so I think Julia would fit right in there.

[1] http://naif.jpl.nasa.gov/naif/

RivieraKid15• 12 years ago

I just use Sublime Text and often copy/paste or include("code.jl") to REPL. I use Eclipse for Java development, but I just don't see a lot of added value for a Julia IDE.

rebo• 12 years ago

Is round(x) broken?

    Julia's standard library includes a host of mathematical functions, in addition to the standard operators. Complex numbers are also supported, using the built-in im unit:

    round(pi) 
    lcm(54, 392, 232) # least common multiple 
    sqrt(square(100)) 
    e^(pi * im) 
    log(e ^ 2) + log10(100)

    When you're ready, type "next" to continue
    julia> round(pi)
    no method round(MathConst{:π},)

Debilski• 12 years ago

round(x) only works for a few specialised types of x. help(round) tells you that it will return the same type then. Of course for a type of MathConst{:π}, that won’t work. For generic types, you need to at least specify the number of digits (round(pi, 3)). (See also: methods(round))

glomph• 12 years ago

Weird that they have round(pi) as an example.

KenoFischer2• 12 years ago

To give some context, several common math constants are use the MathConst type to provide multi-precision constants. This allows e.g. a*pi to be extremely accurate if a is, e.g. a BigInt.

This issue was also reported at https://github.com/JuliaLang/julia/issues/5561

nelmaven• 12 years ago

Everything returns:

   Undefined
   500

Is this broken?

stuinzuri7• 12 years ago

Our Julia REPL servers been slammed. We are shrinking the timeout and bring up more servers. But our capacity is not unlimited. Folks might have to come back later. Sorry about that.

stuinzuri7• 12 years ago

Fixed now. We have added more servers of larger instance types. It should work great now.

sillonleon2• 12 years ago

The Server version of Ubuntu or the 12.04 version does not have the add-apt-repository command. How can i add a PPA to the server without this command? Answer in http://askubuntu.com/questions/38021/how-to-add-a-ppa-on-a-s...

There are several options, I chose the one with sudo gedit /etc/apt/sources.list and

1514 sudo gedit /etc/apt/sources.list 1515 sudo apt-get update #not needed 1516 sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3D3D3ACC 1517 sudo apt-get update 1518 sudo apt-get install julia (there are broken dependencies) 1519 sudo apt-get install libopenblas-base 1520 sudo apt-get update 1521 sudo apt-get install libopenblas-base 1522 sudo apt-get install libatlas-base-dev 1523 sudo apt-get install libopenblas-base 1524 sudo apt-get install julia 1525 julia 1526 history | tail 1527 history | tail -n 20

programminggeek• 12 years ago

Am I crazy for feeling like Julia is the new HN darling like clojure, go, ruby, lisp, and scala before it?

It seems like in the last week it just started popping up on HN every couple days.

pcmonk• 12 years ago

HN goes through phases, which I rather like. This way, we get semi-in-depth coverage of topics serially instead of always uniformly dividing our attention among all interesting projects at the same time.

RivieraKid15• 12 years ago

I hope you're right.

sdegutis7• 12 years ago

It makes sense. We hear about a language, take an initially skeptical approach to it, research it, try it out, and report our findings to others we think might be interested (i.e. HN).

idProQuo• 12 years ago

I don't really see the problem with this. A lot of the languages you mention have been slowly and sustainably building support, even when they aren't on the front page of HN.

charlieflowers2• 12 years ago

Nimrod's turn is coming soon. And it is well-deserving. It has already had some pre-HN-darling attention here, which is what brought it to my attention. I'm very intrigued by it. http://nimrod-lang.org/

acangiano2• 12 years ago

Fun with Julia:

    julia> 3 ** 60
    syntax: use ^ instead of **

    julia> 3 ^ 60
    -3535985420588157519

    julia> factorial(45)
    -8797348664486920192

    julia> factorial(75)
    0

    julia> 5 * 5555555555555555555
    -9115710369641325457

    julia> 5 * 55555555555555555555
    syntax: invalid numeric constant 55555555555555555555

This isn't C. The expectations have changed thanks to scripting languages. If I'm supposed to use this promising language to do calculations and manipulate data, I'd expect to be able to natively handle large numbers without overflowing.

ihnorton6• 12 years ago

Julia supports arbitrary precision arithmetic just fine, but you need to explicitly use it. Overflow checks don't matter in Python or Ruby where everything is relatively slow.

acangiano2• 12 years ago

My point wasn't that it can't be done. My point was about usability and what programmers have come to expect from a modern language. I understand that things get trickier when trying to implement arbitrary-precision arithmetic while keeping performance high.

rdtsc3• 12 years ago

I don't think many here argue that Julia doesn't support it. In fact it would be rather disastrous if it didn't, because it wouldn't make for a very nice scientific language if the biggest int value was 2^64-1.

The question is why aren't large numbers the default, or why doesn't it do automatic up and down conversion and so on.

shele• 12 years ago

Julia uses machine arithmetic for integer computations. The alternatives have serious drawbacks in technical computing, see

http://docs.julialang.org/en/latest/manual/faq/#why-does-jul...

simulate• 12 years ago

Try wrapping each of these in BigInt. Example: factorial(BigInt(1000))

Julia defaults to what is fast on your machine. If you want to use BigInt you can do so but it doesn't do so by default.

You can also use 128bit integers in Julia. Example: rand(Int128, 10)

KenoFischer2• 12 years ago

BTW, the invalid numeric constants thing was fixed

    julia> 55555555555555555555
    55555555555555555555

    julia> typeof(55555555555555555555)
    Int128

    julia> typeof(5555555555555555555555555555555555555555)
    BigInt (constructor with 7 methods)

RivieraKid15• 12 years ago

Yes, Julia doesn't auto-convert to BigInt, it's a trade-off between performance and easy-to-useness, but they've definitely made the right decision.

You have to convert to BigInt or BigFloat like this:

   julia> big(3) ^ 60
   42391158275216203514294433201

rdtsc3• 12 years ago

Why not have them as BigInt and donwconvert to machine sized ints explicitly?

In any case. If you think of it as a nicer C, it works very well. It is a slight disappointment if you think of it as a nicer Python.

sillonleon2• 12 years ago

Julia is very fast, 0.12 second, 0.60 second for sbcl (lisp)

julia>function haz(n) s = 0 for i in 1:n if i % 2 == 0 s = s+1 else s = s-1 end end s end haz (generic function with 1 method)

julia> @elapsed haz(10^8) 0.12459633

Compare with lisp sbcl on the same machine:

(defun haz(n) (let ((s 0)) (declare (optimize (speed 3) (safety 0)) (fixnum n s)) (loop for i fixnum from 1 upto n do (if (zerop (mod n 2)) (incf n) (decf n)) finally (return s))))

Stubb9• 12 years ago

Julia appears to be a perfect fit for much of what I do at work. I tried it, got very excited, and then facepalmed earlier today. Let's define two functions in the REPL:

    function foo()
      return 42
    end

    function bar()
      return foo()
    end

Evaluating bar() gives 42, just as one would expect.

Now let's redefine foo():

    function foo()
      return 69
    end

Evaluating bar() still gives 42!

Not getting something so basic correct tells me to avoid the whole thing for fear of getting subtly screwed by some other oversight. Actually, oversight isn't the right word, since broken automatic compilation has been a known problem for two years: https://github.com/JuliaLang/julia/issues/265.

RivieraKid15• 12 years ago

That annoys me too but it isn't a big deal, it'll probably get fixed in the future.

Stubb9• 12 years ago

You change a function, and that change doesn't get reflected in upstream calls—this isn't a big deal? Are you kidding me?

ihnorton6• 12 years ago

Not getting something so basic correct tells me to avoid the whole thing for fear of getting subtly screwed by some other oversight.

No one denies that this is a problem, and it will be fixed. But I disagree that it represents a fundamental flaw. For iterative development, it is a minor inconvenience, so other priorities have taken precedence. If you are redefining functions in this way in tested code, there may be bigger problems to worry about.

The Julia developers have paid fastidious attention to correctness (to the point of making a pilgrimage to visit Kahan early on). The type system is well thought-out and nice to use. Spurious crashes are almost nonexistent (and fixed within hours, without fail). The foundation is solid, but it's still a work in progress, and it will take some time to shake these sorts of features out.

Stubb9• 12 years ago

I was cheering out loud when I first downloaded Julia and started working with it. The type system, multiple dispatch, so much win! I'm working on ionospheric ray tracing at my day job and would love to use Julia.

But when I can write a nine-line example that produces incorrect output—no thanks. Especially when one of the lead developers (see the linked thread) states that supporting function redefinition isn't needed for v1.0. Clearly these people are working under a very different set of priorities than me.

"The foundation is solid"—I do not think it means what you think it means.

charlieflowers2• 12 years ago

(to the point of making a pilgrimage to visit Kahan early on)

What does that mean?

plg2• 12 years ago

A lot of the comments I see about Julia (and other trendy high level languages) are of the following form:

"I can do things I needed C to do before, and almost as fast"

which leads me personally to ask,

If you could do this in C before, and faster, then why are you switching?

Most people will say "because C is bad/difficult/clumsy for doing X"

which leads me to say,

why are you using C to do X?

I sincerely believe (as a computational scientist) that a combination of a high-level language for real-time interactive exploration and prototyping with a fast language like C for doing the actual gruntwork, is the best.

Attempts to combine the best of C (speed) with the best of scripting languages (easy to do things fast without having to pay attention to what you are doing) in my opinion end up merely joining the worst of both worlds rather than the best of both worlds.

Besides isn't programming about being specific? Do you really want to code stuff without having to worry about the details?

catinsocks• 12 years ago

You can see it as an alternative to Matlab/R (sorta)/numpy not C.

People only ever used C when speed was crucial and depending on what you were comfortable in or what you had learned maybe Fortran for speed instead of C.

Julia is meant for scientific computing with some nice features. As I see it it is similar enought to Matlab to be easily learned by those who use Matlab but has enough goodies that it can be a viable alternative.

Programming isn't about being specific it is about accomplishing a task and many times yes you don't want to have to worry about the details as long as it works the way it should.

plg2• 12 years ago

I agree with what you say. More and more though as I get on in my career as a scientist I realize though that the details turn out to matter, sometimes a great deal.

Anyway I'm all in favour of an open, fast MATLAB alternative

RivieraKid15• 12 years ago

I sincerely believe (as a computational scientist) that a combination of a high-level language for real-time interactive exploration and prototyping with a fast language like C for doing the actual gruntwork, is the best.

Converting to C can take a LOT of time, and is an order of magnitude less enjoyable than Julia. What about maintaining the code, making improvements, integrating with other code? And what if the prototyping needs too be fast too? It can become a massive pain in the ass. Why should I undergo that if I can just use Julia?

Attempts to combine the best of C (speed) with the best of scripting languages (easy to do things fast without having to pay attention to what you are doing) in my opinion end up merely joining the worst of both worlds rather than the best of both worlds.

I've used both Julia and C and I think it's the exact opposite, it combines the best of both worlds.

coldtea7• 12 years ago

which leads me to say, why are you using C to do X?

Because they know C, it's fast and it has lots of libs available. They might also dislike Java or CL.

Not every engineering decision is perfect, lots of factors play in.

Attempts to combine the best of C (speed) with the best of scripting languages (easy to do things fast without having to pay attention to what you are doing) in my opinion end up merely joining the worst of both worlds rather than the best of both worlds.

The "pay attention" things is to needless complexity (memory management etc). They only reason we put up with those things was to get speed. If we can get adequate speed without those, nobody cares about them.

Besides isn't programming about being specific? Do you really want to code stuff without having to worry about the details?

No, programming is about getting results. Nobody cares about the details in the level of programming language minutuae.

We care about the "effort put in" and "quality/speed of results coming out" ratio.

elwell• 12 years ago

no method round(MathConst{:π},)

eskimo87• 12 years ago

joshfraser• 12 years ago

The pi constant didn't work for me

axilmar• 12 years ago

After typing next about 20 times without seeing anything interesting, I quit.

Try Julia

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