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Giving up on Julia

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Re: Giving up on Julia

#191

Post by garyclarke27 »

jandrese wrote: post #50
bmh100 wrote: post #41

Earlier quoted context omitted.

One-based indexing is also used in Fortran, which seems to be used in a great deal of numerical computing even today. Additionally, BLAS/LAPACK is an important linear algebra library written in Fortan. I am somewhat confused by your discussion of startup times. Since Julia is a "programming language for technical computing", what scenario are you imagining where startup times would be a significant concern?

No less than Dykstra has weighed in on the numbering of arrays. http://www.cs.utexas.edu/users/EWD/ewd08xx/EWD831.PDF Having worked with both, I'm inclined to prefer 0 based addressing in most cases. It's slightly less intuitive, but it generally leads to cleaner code.

I don't buy the Dykstra argument,1 base is more intuitive for me and for most non programmers, I would guess. Funny though how Americans use 1 based indexing for building floor numbers, but Europeans use zero based i.e. ground floor is zero in a European lift, 1 in a US lift.

Re: Giving up on Julia

#192

Post by sgt101 »

lqdc13 wrote: post #186
MikeHolman wrote: post #94

Earlier quoted context omitted.

Were you using a js runtime without a JIT? Were your python algorithms better? Otherwise a 200x speedup sounds completely unbelievable. That would basically indicate a bug in the js runtime causing degenerate performance under your scenario.

That's very believable. Example: popping from the beginning of a list in Python is O(N). Popping from the end is O(1). Initial poorly written code can have a lot of such obvious optimizations.

It's a common programming thing - you write your code, it compiles, it runs, it runs properly on your test case, you try it on your full data, it's too slow. You run your profiler and you spot some problems, you solve them, it's still too slow, repeat until fast enough, declare victory.

Re: Giving up on Julia

#193

Post by sgt101 »

sndean wrote: post #35
Frompo wrote: post #15

If you want to replace Matlab you should use Octave, julia is for making your next climate model, not for "hello world" ricing

I've found the Armadillo C++ library ( http://arma.sourceforge.net/ ) to be a better replacement, when concerned about speed.

But speed has multiple dimensions. Yes, you can get things to go faster, quicker with three tactics : get closer to the iron (C, C++ - sometimes), use bigger iron (clusters) or (best) better programming. But the point of Julia is that at the end of the day the second and third tactic are easier for you, and not just you, everybody in the team and beyond.

On the other hand everyone knows that Julia is 0.x which means that while this is the IDEA of Julia it's still not claimed as the reality - although my experience (and some other people) is that it's pretty true most of the time.

Re: Giving up on Julia

#194

Post by SolarNet »

sgt101 wrote: post #189
SolarNet wrote: post #164

Earlier quoted context omitted.

I'm referring to one specific core dev. However they all know each other from MIT so it makes it difficult for them to deal with that fact. I can point to 3 public examples, in addition to a couple of private reports about problems which allow me to be certain. But admittedly it's all second hand to me (from people who work close to the language).

Perhaps you might consider adding a note to your first post making it clear that you are identifying a problem with one other person rather than the whole community and that this is all second hand rather than your own experience?

You realize edit timers are a thing right?

Re: Giving up on Julia

#195

Post by hbogert »

pygy_ wrote: post #117
banku_brougham wrote: post #108

Earlier quoted context omitted.

no less than dykstra was convicted of grand theft auto. https://en.wikipedia.org/wiki/Lenny_Dykstra I think you mean Dijkstra, who did say that, because of an argument with mathematicians about indexing from 1.

In Dutch, ij and ÿ are interchangeable.

In print, NO. You really can't interchange the two. As already said, in handwriting they may look similar, however we would never mean the actual ÿ, since it simply is something else which is used in Greek and French (and others).

There's even a section about this on wikipedia: https://en.m.wikipedia.org/wiki/IJ_(digraph) subsection "technical details".

Re: Giving up on Julia

#196

Post by sgt101 »

IshKebab wrote: post #45
unlinker wrote: post #34

Earlier quoted context omitted.

Why is strong/dynamic typing considered such a big deal?

Two main reasons: 1. You can detect very common errors (e.g. typos) at compile-time instead of maybe detecting them at run-time. This makes the code much much more reliable (or equivalently you don't need to do nearly as much testing). 2. Dynamic typing prevents IDEs from doing extremely useful things like real code completion and symbol renaming. If you're thinking "but I edit Javascript with code completion" or "co…

Also static types tell the machine what is supposed to happen next, and always. Dynamic types represent possibilities that have to be maintained as open until they become commitments that have to be remembered. Static types are certainties that come as orders. Dynamic typing is like being in love, Static typing is like being in the Army.

(disclaimer, I have never been in the Army or any military force and the above post is based on my imagination and watching films)

Re: Giving up on Julia

#198

Post by dagw »

MikeHolman wrote: post #94
dagw wrote: post #55

Earlier quoted context omitted.

I've gotten 200x speedup going (badly written) Javascript to (better written) pure python, despite python being a nominally slower language according micro-benchmarks. Comparing run time without knowing anything about the code doesn't say much.

Were you using a js runtime without a JIT? Were your python algorithms better? Otherwise a 200x speedup sounds completely unbelievable. That would basically indicate a bug in the js runtime causing degenerate performance under your scenario.

I replaced some inefficient code with some better O(n log n) code. Make n large and you'll get to 200x. Which was kind of my point, without making sure you've held every else the same, saying I rewrote X in Y and got Z improvement doesn't always say that much.

Re: Giving up on Julia

#199

Post by Fede_V »

Julia aside, Keno, kudos for being an absolute class act and replying to everything so politely.

For what it's worth, my impression of Julia has been overwhelmingly positive, and all the developers I've interacted with have been polite and friendly. I haven't made the switch from Python because:

- I prefer the Python syntax

- I like Python libraries (I know about PyCall, and it rocks)

- The increased speed of Julia doesn't really add much given numba/theano and so forth

However, I really like:

- Optional static typing for sanity checking

- Can write fast functions directly in julia - which is handy when passing callbacks or doing numerical routines like integration (although this requires timholy's fast lambda package)

Re: Giving up on Julia

#200

Post by pygy_ »

hbogert wrote: post #195
pygy_ wrote: post #117

Earlier quoted context omitted.

In Dutch, ij and ÿ are interchangeable.

In print, NO. You really can't interchange the two. As already said, in handwriting they may look similar, however we would never mean the actual ÿ, since it simply is something else which is used in Greek and French (and others). There's even a section about this on wikipedia: https://en.m.wikipedia.org/wiki/IJ_(digraph) subsection "technical details".

At the very least it happens in Flanders. I've seen ijs ("ice") capitalized in cursive as Ys[0] on an ice truck, for example.

Edit: from Wikipedia[1]: "It used to be common, in particular when writing in capitals, to write Y instead of IJ."

So it's an obsolete practice...

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0. something along those lines: http://alphabetprintables.org/alphabet_printables_cursive/up...

1. https://en.wikipedia.org/wiki/IJ_%28digraph%29

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