Re: [julia-users] A Test Matrix Collection for Julia

2014-11-26 Thread Weijian Zhang
Dear Tamas, Thanks for your suggestion. After seeing your post, I spent some time trying to know the difference between symbols and strings. This stackoverflow post http://stackoverflow.com/questions/23480722/what-is-a-symbol-in-julia was helpful. I think both symbols and strings are fine

[julia-users] Re: Significant rounding error in Julia: N * (1/1) == N + 1

2014-11-26 Thread Mike Innes
Woops, shouldn't have missed this thread. Either way I just pushed 0.9.1 which turns off all rounding in display. On Thursday, 20 November 2014 10:59:25 UTC, Ken B wrote: for reference, here is the issue https://github.com/one-more-minute/Julia-LT/issues/114 I've been bitten by this one

[julia-users] Re: PyPlot.plot_date: How do I alter the time format?

2014-11-26 Thread RecentConvert
using PyPlot using Dates # Create Data dt = Millisecond(200) time = [DateTime(2014,11,20):dt:DateTime(2014,11,24)] y = fill!(Array(Float64,length(time)),42) #y = floor(100*rand(length(time))) # Causes error: OverflowError: Allocated too many blocks font1 = [fontname=Sans,style=normal] time =

Re: [julia-users] Re: Meshgrid in Julia: a working example and possible alternatives

2014-11-26 Thread Steven G. Johnson
On Wednesday, November 26, 2014 12:45:09 AM UTC-5, David Smith wrote: My up-to-date version of Matplotlib won't plot NaNs either. That's weird; it works fine for me in Matplotlib 1.4.0. In any case, you can always zero out the NaN values in W via: W[isnan(W)] = 0 before plotting.

[julia-users] Re: [Offtopic:] Why you did choose the name Julia?

2014-11-26 Thread Neal Becker
All the good names were taken :) Pileas wrote: Is there a specific reason you guys chose this name? It kinda reminds me Linux Mint where each distro. has a girl's name ... -- -- Those who don't understand recursion are doomed to repeat it

[julia-users] Q4 2014 Lint.jl update

2014-11-26 Thread Tony Fong
Fellow Julia enthusiasts, It seems a quarterly update to Lint.jl carries enough weight without being overwhelming, so here it is again. Here are the new abuses that would be caught. Most of them I encountered them the hard way, so hopefully new users won't random-walk into them. - A first

[julia-users] Re: PyPlot.plot_date: How do I alter the time format?

2014-11-26 Thread Nat Wilson
You might try something like: majorformatter = matplotlib[:dates][:DateFormatter](%m/%d) minorformatter = matplotlib[:dates][:DateFormatter](%H:%M) majorlocator = matplotlib[:dates][:DayLocator](interval=1) minorlocator = matplotlib[:dates][:HourLocator](byhour=(8, 16))

[julia-users] Memory allocation issue

2014-11-26 Thread Colin Lea
I'm implementing an inference algorithm and am running into memory allocation issues that are slowing it down. I created a minimal example that resembles my algorithm and see that the problem persists. The issue is that Julia is allocating a lot of extra memory when adding matrices together.

[julia-users] Re: simplex in Julia is very slow

2014-11-26 Thread cdm
a search of the julia-users list for the string simplex yields nine posts ... since an attribute of benchmarking is speed/timing, this post stood out: https://groups.google.com/forum/?fromgroups=#!searchin/julia-users/simplex|sort:date/julia-users/QCPHX63r0oQ/mheoSJqD96YJ within that

[julia-users] Re: Constant attributes of Composite Type

2014-11-26 Thread Robert Gates
OK thanks John, I ended up doing a bit differently but it works fine. Sorry to keep asking, but now I have another problem I can't seem to wrap my head around: consider my_type_collection = Vector{MyType} my_type_collection[1] = MyType(a,b,c) returns: `setindex!` has no method matching

[julia-users] Re: Q4 2014 Lint.jl update

2014-11-26 Thread Nils Gudat
Hi Tony, I've only been using Lint for two days, so I might be doing it wrong, but I'm getting a lot of false positives about values I've declared, but not used - upon closer inspection of my code, they are almost always used, sometimes within loops, sometimes in if/else branches, sometimes as

Re: [julia-users] Re: Constant attributes of Composite Type

2014-11-26 Thread John Myles White
Vector{MyType} is a type, not a value. Did you mean Array(MyType, 1)? — John On Nov 26, 2014, at 8:38 AM, Robert Gates robert.ga...@gmail.com wrote: OK thanks John, I ended up doing a bit differently but it works fine. Sorry to keep asking, but now I have another problem I can't seem to

[julia-users] Re: Q4 2014 Lint.jl update

2014-11-26 Thread Nils Gudat
Another thing: Consider the following example X1 = zeros(100, 100) X2 = Array(Float64, (100, 100)) X1[1, 1] X2[1, 1] In this piece of code, I will get an error saying X2[1, 1] has more indices than dimensions, even though it hasn't. In light of the recent discussion on this list about the

[julia-users] Re: Q4 2014 Lint.jl update

2014-11-26 Thread Tony Fong
Ah yes, array related type checks is a major issue. See https://github.com/tonyhffong/Lint.jl/issues/27 Post your issues there and we should be able to knock them off. It's not difficult, just need to know where the priorities are. Tony On Wednesday, November 26, 2014 11:49:58 PM UTC+7, Nils

[julia-users] Re: simplex in Julia is very slow

2014-11-26 Thread Emerson Vitor Castelani
Have you considered the example scsd8.mat? Em quarta-feira, 26 de novembro de 2014 14h39min14s UTC-2, Pileas escreveu: Result with tic() toc() at the very beginning and at the very end: elapsed time: 0.025719973 seconds Τη Τετάρτη, 26 Νοεμβρίου 2014 11:06:26 π.μ. UTC-5, ο χρήστης Emerson

[julia-users] Re: Q4 2014 Lint.jl update

2014-11-26 Thread Tony Fong
On Wednesday, November 26, 2014 11:41:09 PM UTC+7, Nils Gudat wrote: An example: function f{T:Float64}(x1::T, x2::T, x3::Array) will give me Error: Float64 is a leaf type. As a type constraint it makes no sense in T:Float64. I thought this was a way of efficiently expressing that both x1

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Stefan Karpinski
I'm not sure if this is the problem, but changing the type of a variable in a function body causes problems for type inference. For that reason, the first two lines of this code may cause performance issue if you call this with b and c as matrices. A more Julian idiom for this is to do something

Re: [julia-users] Memory allocation issue

2014-11-26 Thread Milan Bouchet-Valat
Le mercredi 26 novembre 2014 à 07:55 -0800, Colin Lea a écrit : I'm implementing an inference algorithm and am running into memory allocation issues that are slowing it down. I created a minimal example that resembles my algorithm and see that the problem persists. The issue is that Julia

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Emerson Vitor Castelani
Humm, It's useful but I guess that the problem is something in loop while... Em quarta-feira, 26 de novembro de 2014 15h05min03s UTC-2, Stefan Karpinski escreveu: I'm not sure if this is the problem, but changing the type of a variable in a function body causes problems for type inference.

Re: [julia-users] Re: what's the best way to do R table() in julia? (why does StatsBase.count(x,k) need k?)

2014-11-26 Thread David van Leeuwen
Hello again, I worked hard on NamedArrays.jl to solve the problems indicated below: On Monday, November 10, 2014 1:43:57 AM UTC+1, Dahua Lin wrote: NamedArrays.jl generally goes along this way. However, it remains limited in two aspects: 1. Some fields in NamedArrays are not declared of

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Milan Bouchet-Valat
Le mercredi 26 novembre 2014 à 09:26 -0800, Emerson Vitor Castelani a écrit : Humm, It's useful but I guess that the problem is something in loop while... If I were you I'd have a look at where time is spent are where allocations are happening, and try to improve this by writing explicit loops

Re: [julia-users] Memory allocation issue

2014-11-26 Thread Tim Holy
Nice job using track-allocation to figure out where the problem is. If you really don't want allocation, then you should investigate Devec.jl or InPlaceOps.jl, or write out these steps using loops to access each element of those matrices. --Tim On Wednesday, November 26, 2014 07:55:59 AM

[julia-users] Re: Significant rounding error in Julia: N * (1/1) == N + 1

2014-11-26 Thread Pileas
It does not happen in my machine either. Τη Τετάρτη, 19 Νοεμβρίου 2014 2:47:20 μ.μ. UTC-5, ο χρήστης Intrinsic Audio έγραψε: I've found an interesting issue in Julia that, though it seems trivial in the application I've given, is really messing up my code and my ability to guarantee its

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Tim Holy
Stefan's point is more relevant than you realize; if the type of the variable is uncertain, the loop will be very slow. You can make that resize operation a separate function, from which you call your main routine. --Tim On Wednesday, November 26, 2014 09:26:35 AM Emerson Vitor Castelani

[julia-users] SharedArray no longer shared after loading from jld file

2014-11-26 Thread Ariel Keselman
Consider the following simple example: using HDF5, JLD addprocs(2) # create and save the shared array a = SharedArray(Int64, 100) save(example.jld, a, a) # clear the shared array... a = nothing # load what we saved... a = load(example.jld)[a] # try to use it... @parallel for i in 1:length(a)

Re: [julia-users] Memory allocation issue

2014-11-26 Thread Colin Lea
Thanks to you both! However, there is still another odd issue. These two functions should be the same, but take very different amounts of time/memory. Both 'T' and 'n_classes' are both of type Int64. @time ( for t = 2:T for n = 1:n_classes for j = 1:n_classes

Re: [julia-users] Memory allocation issue

2014-11-26 Thread John Myles White
Are these functions? Or are you timing expressions in the global scope? -- John On Nov 26, 2014, at 10:28 AM, Colin Lea colin...@gmail.com wrote: Thanks to you both! However, there is still another odd issue. These two functions should be the same, but take very different amounts of

Re: [julia-users] Memory allocation issue

2014-11-26 Thread Colin Lea
That was in global scope. Should that matter? On Nov 26, 2014, at 1:30 PM, John Myles White johnmyleswh...@gmail.com wrote: ?

Re: [julia-users] Memory allocation issue

2014-11-26 Thread John Myles White
Yes, the global scope is scarcely optimized and doesn't provide useful information about performance. -- John On Nov 26, 2014, at 10:33 AM, Colin Lea colin...@gmail.com wrote: That was in global scope. Should that matter? On Nov 26, 2014, at 1:30 PM, John Myles White

[julia-users] Re: SharedArray no longer shared after loading from jld file

2014-11-26 Thread Ariel Keselman
One more issue: The example above can be fixed by reassigning `a` to a new shared array. But in my case this won't work since I have this array within a wrapper type... seems like another semi related issue?

Re: [julia-users] Memory allocation issue

2014-11-26 Thread Colin Lea
Ah, ok. Thanks! I ran those as functions and got similar timings. On Nov 26, 2014, at 1:35 PM, John Myles White johnmyleswh...@gmail.com wrote: Yes, the global scope is scarcely optimized and doesn't provide useful information about performance. -- John On Nov 26, 2014, at 10:33

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Stefan Karpinski
It turns out that doesn't actually matter but there are other unrelated ill-typed variables in the code: Xb, o, y, r, e, Nj, ind, q, t I haven't determined why this is happening, but something is ill-typed here. On Wed, Nov 26, 2014 at 1:20 PM, Tim Holy tim.h...@gmail.com wrote: Stefan's

Re: [julia-users] simplex in Julia is very slow

2014-11-26 Thread Stefan Karpinski
I wonder if \ might be type unstable. On Wed, Nov 26, 2014 at 2:49 PM, Stefan Karpinski ste...@karpinski.org wrote: It turns out that doesn't actually matter but there are other unrelated ill-typed variables in the code: Xb, o, y, r, e, Nj, ind, q, t I haven't determined why this is

[julia-users] Flexible construction of types

2014-11-26 Thread Marc Gallant
Suppose I have a type called MyType that has one floating point field x. When constructed, if the value provided for x is greater than, let's say, 5, it has pi subtracted from it. For example, a = MyType(4) # x = 4.0 b = MyType(-11) # x = 11.0 c = MyType(10) # x = 6.8584 d = MyType(-1.443) #

Re: [julia-users] Flexible construction of types

2014-11-26 Thread Mauro
How about immutable MyType{T:Real} x::T v::Vector{T} s::String function MyType(x, v, s) x = subtractpi(x) v = map(subtractpi, v) new(x, v, s) end end MyType{T1:Real, T2:Real}(x::T1, v::Vector{T2}, s::String) = (T=promote_type(T1,T2); MyType{T}(x, v,

Re: [julia-users] Flexible construction of types

2014-11-26 Thread Marc Gallant
Thanks for your quick response! I have a couple questions/concerns about your implementation: - MyType(1, [2, 3], xyz) fails requirement #2 - MyType(1, [2, 10], xyz) throws InexactError() - Does the declaration s::String cause the ambiguities described in the FAQ here

Re: [julia-users] Re: Neuro-Dynamic Programming in Julia

2014-11-26 Thread wildart
Defining an RL-agent environment in RL-Glue API is a straightforward task. Apart from (de)initialization calls, an environment respond for the agent action must me defined. This respond should have an appropriate reward for the agent (There are two separate placeholders for integer and real

Re: [julia-users] Flexible construction of types

2014-11-26 Thread Mauro
Thanks for your quick response! I have a couple questions/concerns about your implementation: - MyType(1, [2, 3], xyz) fails requirement #2 MyType{T1:Real, T2:Real}(x::T1, v::Vector{T2}, s::String) = (T=promote_type(T1,T2,Float64); MyType{T}(x, v, s)) If you want to keep Float16, etc this

Re: [julia-users] Flexible construction of types

2014-11-26 Thread Jameson Nash
it should be noted that there's nothing inherently wrong or bad about using non-concrete type specifications in type declarations. it does, however, limit certain optimizations that might provide performance benefits, and may be especially important for native numerical types. On Wed Nov 26 2014

Re: [julia-users] Re: Meshgrid in Julia: a working example and possible alternatives

2014-11-26 Thread Pileas
I found out that the code works when I use IJulia, but not when I run the command: julia file.jl. This is weird indeed ... Τη Τετάρτη, 26 Νοεμβρίου 2014 9:05:32 π.μ. UTC-5, ο χρήστης Steven G. Johnson έγραψε: On Wednesday, November 26, 2014 12:45:09 AM UTC-5, David Smith wrote: My

Re: [julia-users] JuliaBox

2014-11-26 Thread Zenna Tavares
I would like to get an invite code if at all possible. Thanks! Zenna On Saturday, November 15, 2014 4:07:51 AM UTC-5, Viral Shah wrote: Yes, we certainly want to add GitHub to the mix. -viral On 14-Nov-2014, at 7:16 pm, Daniel Carrera dcar...@gmail.com javascript: wrote:

Re: [julia-users] Installing IJulia

2014-11-26 Thread Abram Demski
Pileas, Given that I've still been unable to install IJulia, that's very helpful, thanks. On Tue, Nov 25, 2014 at 6:29 PM, Pileas phoebus.apollo...@gmail.com wrote: I have to suggest a very good editor that supports Julia and it is called Atom. It becomes better each day: Give it a try if

[julia-users] Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread Test This
I have the following function defined to check whether a record exists in a Mongodb database (thanks a million for PyCall, which make it easy to use pymongo to interact with mongodb in julia). function doesrecexist(collectn::PyObject, rec::Dict{ASCIIString,Any}) # checks if record

[julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread Patrick O'Leary
On Wednesday, November 26, 2014 6:01:56 PM UTC-6, Test This wrote: I have the following function defined to check whether a record exists in a Mongodb database (thanks a million for PyCall, which make it easy to use pymongo to interact with mongodb in julia). function

[julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread Test This
Patrick, thank you for your response and the link. I will need to read it more carefully and try to understand as it since it deals with concepts I am not familiar with. However, wouldn't the solution you proposed restrict all values of the rec Dict to the same type in any given call. Am I

Re: [julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread K Leo
I ran into similar mental difficulty regarding whether type Any is a superset of any other types. I did not find anything to read, but simply accepted the fact through painstaking experiments. I think the word Any here is confusing. The English definition of it means that it ought to

Re: [julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread John Myles White
All types do have Any as a parent. It is clear that many people are confused about what covariance, contravariance and invariance mean in computer science. As such, I very strongly encourage everyone who isn't sure that they understand Julia's type system to read through the wikipedia article

Re: [julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread elextr
It is demonstrated in the manual at http://docs.julialang.org/en/release-0.3/manual/types/#parametric-composite-types that parametric types do not have any relationship even if their parameter types have some relationship. Perhaps it would be better emphasise that and to explain it simply

[julia-users] Re: Animation with Gadfly and IJulia?

2014-11-26 Thread Sheehan Olver
I figured out an approach that works for animation, thanks to Jiahao Chen, using 2 IJulia inputs: # In[1] using ApproxFun,Gadfly,Reactive x=Input(Fun(exp)) lift(ApproxFun.plot, x) # In[2] for k=1:10 push!(x,Fun(x-cos(k*x))) end On Tuesday, November 4, 2014 2:46:44 AM UTC-6, Sheehan

[julia-users] julia vs cython benchmark

2014-11-26 Thread Andre Bieler
Did a benchmark for calculating shadowing of a triangulated surface mesh in julia and cython. It is basically a loop over all surface elements and checks if any other of the surface elements intersect with the line of sight pointing towards a light source. (see pic below, light source on the

Re: [julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread K Leo
Thanks, now I understand it. The problem I had was this, which I imagine to exist with many other non-computer scientists new to Julia. This topic is discussed under the parametric type section of the manual, and since I had not attempted to use parametric types (the things with the

[julia-users] Re: julia vs cython benchmark

2014-11-26 Thread Jeff Waller
There is one thing is see as a potential. The outer loop *i* is incrementing the first index, and Julia stores things in column-major order, so any speed gain from CPU cache is potentially lost since you using elements that are not contiguous in the inner loops.

Re: [julia-users] Installing IJulia

2014-11-26 Thread cdm
if you are not averse to trying IJulia in your browser, then have a look at this post ... https://groups.google.com/forum/#!searchin/julia-users/tmpnb|sort:relevance/julia-users/zEp8pKkEYHk/qY7tPqrOp9gJ there are other ways to work with IJulia on kernels hosted elsewhere; let me know if

Re: [julia-users] Installing IJulia

2014-11-26 Thread stonebig34
Hi Abram, If all else fails, you have still this alternative http://nbviewer.ipython.org/github/winpython/winpython_afterdoc/blob/master/examples/installing_julia_and_ijulia.ipynb On Thursday, November 27, 2014 6:57:41 AM UTC+1, cdm wrote: if you are not averse to trying IJulia in your

Re: [julia-users] Re: Is Dict{ASCIIString, Any} not a superset of Dict{ASCIIString, Float64}?

2014-11-26 Thread Ivar Nesje
The explanation that made me stop suggesting that `Sometype{T1} : Sometype{T2} if T1:T2` was the following function: function foo( a::Array{Any, 1}) # I can now get objects from the array, and they will be subtypes of Any b = a[1] # And I can insert Any object into the array