[julia-users] Re: Does a wrapper for gmtime exist

[Andrew Gibb]

Thanks both for the suggestions. 

On Wednesday, 27 July 2016 19:54:38 UTC+1, Jeffrey Sarnoff wrote:
>
> Andy,
>
> You are welcome to use https://github.com/J-Sarnoff/UTime.jl
>
> Pkg.clone("https://github.com/J-Sarnoff/UTime.jl;)
> using UTime
>
> localtime()
> 2016-07-27T14:41:37.497-04:00
>
> ut()
> 2016-07-27T18:41:42Z
>
> gmt() # gmt aliases ut
> 2016-07-27T18:41:45Z
>
> alocaltime = localtime()
> 2016-07-27T14:42:04.282-04:00
> ut(alocaltime)
> 2016-07-27T18:42:04.282Z
>
> auniversaltime = ut()
> 2016-07-27T18:42:24Z
> localtime(auniversaltime)
> 2016-07-27T14:42:24-04:00
>
> julia> g=gmt(); g
> 2016-07-27T18:50:48Z
>
> julia> year(g),month(g),day(g),hour(g),minute(g),second(g)
> (2016,7,27,18,50,48)
>
>
>
> There is more that one may do using UTime, take a look at the README 
> examples.
>
>
> It has been some time since I revisited it, so please ask if you have any 
> questions, 
> and let me know if there is something that is not now working as it had.
> I just ran the examples above in v0.5-.
>
> Regards, 
> Jeffrey
>
> On Wednesday, July 27, 2016 at 9:32:56 AM UTC-4, Andrew Gibb wrote:
>>
>> Hi,
>>
>> I'm writing a module for dealing with video timing. The C++ code I'm 
>> using as a basis uses gmtime to convert seconds into y:m:d.etc. Does anyone 
>> know if this functionality is exposed in Julia anywhere?
>>
>> I realise I could handle this myself with ccall, I just wanted to check 
>> to see if I could avoid duplicating effort.
>>
>> Thanks
>>
>> Andy
>>
>

[julia-users] Does a wrapper for gmtime exist

[Andrew Gibb]

Hi,

I'm writing a module for dealing with video timing. The C++ code I'm using 
as a basis uses gmtime to convert seconds into y:m:d.etc. Does anyone know 
if this functionality is exposed in Julia anywhere?

I realise I could handle this myself with ccall, I just wanted to check to 
see if I could avoid duplicating effort.

Thanks

Andy

Re: [julia-users] Julia text editor on iPad?

[Andrew Gibb]

Is there a way to do shift-enter to execute a cell using the iPad software 
keyboard? Does shift enter just work on the hardware keyboard?

Re: [julia-users] Forming run() calls programatically

[Andrew Gibb]

Those methods both work, and help me understand metaprogramming a little.

Thanks to you both.

[julia-users] Forming run() calls programatically

[Andrew Gibb]

I'm trying to use metaprogramming to create two functions. Each of which 
includes a similar, long, call to run(). The calls are not quite identical. 
Some flags have different arguments, and some are only present on one call. 
I can't work out how to get expression interpolation to happen within 
command interpolation. For example:

for (fn, arg) = ((:toucha, "a"), (:touchb, "b"))
#@eval ($fn)() = run(`touch $arg`)
@eval ($fn)() = run(`touch $(@eval ($arg))`)
end

In the first of these cases, the result for toucha is
toucha() = run(`touch $arg`)

and similarly for the second result, the parsing character $ is ignored by 
the eval. Is there a way to get this to instead return
toucha() = run(`touch a`)

?

Re: [julia-users] Re: Rounding to zero from positive or negative numbers results in positive or negative zero.

[Andrew Gibb]

On Wednesday, 20 April 2016 15:18:06 UTC+1, Stefan Karpinski wrote:
>
> IEEE has not made the programming language designer's life easy here.
>

Perhaps it's a subtle attempt to incentivise more designers of mathematical 
programming languages into IEEE standards committees?!

 

>
> On Wed, Apr 20, 2016 at 5:51 AM, Milan Bouchet-Valat  > wrote:
>
>> Le mardi 19 avril 2016 à 22:10 -0700, Jeffrey Sarnoff a écrit :
>> > Hi,
>> >
>> > You have discovered that IEEE standard floating point numbers have
>> > two distinct zeros: 0.0 and -0.0.  They compare `==` even though they
>> > are not `===`.  If you want to consider +0.0 and -0.0 to be the same,
>> > use `==` or `!=` not `===`  or `!==` when testing floating point
>> > values (the other comparisons <=, <, >=, > treat the two zeros as a
>> > single value).
>> There's actually an open issue about what to do with -0.0 and NaN in
>> Dicts: https://github.com/JuliaLang/julia/issues/9381
>>
>> It turns out it's very hard to find a good solution.
>>
>>
>> Regards
>>
>> > > Hello everyone!
>> > > I was wondering if the following behavior of round() has an special
>> > > purpouse:
>> > >
>> > > a = round(0.1)
>> > > 0.0
>> > >
>> > > b = round(-0.1)
>> > > -0.0
>> > >
>> > > a == b
>> > > true
>> > >
>> > > a === b
>> > > false
>> > >
>> > > bits(a)
>> > > ""
>> > >
>> > >
>> > > bits(b)
>> > > "1000"
>> > >
>> > > So the sign stays around...
>> > >
>> > > I am using this rounded numbers as keys in a dictionary and julia
>> > > can tell the difference. 
>> > >
>> > > For example, I expected something like this:
>> > > dict = [i => exp(i) for i in [a,b]]
>> > > Dict{Any,Any} with 1 entry:
>> > >  0.0 => 1.0
>> > >
>> > > but got this:
>> > > dict = [i => exp(i) for i in [a,b]]
>> > > Dict{Any,Any} with 2 entries:
>> > >   0.0  => 1.0
>> > >   -0.0 => 1.0
>> > >
>> > > It is not a big problem really but I would like to know where can
>> > > this behaviour come handy.
>> > >
>> > > Cheers!
>> > >
>>
>
>

Re: [julia-users] 'do' notation in documentation?

[Andrew Gibb]

I have a little document which I add to periodically called "Julia 
unsearchables" where I note down which things can't be found in the docs 
without asking someone. I do hope, once my Thesis is done, that I can 
contribute it to the documentation. 

[julia-users] Reusing memory with FileIO

[Andrew Gibb]

Hi,

I'm doing work reading image sequences using Images.jl. I haven't been able 
to find in the docs for Images or FileIO a reference for how to load an 
image into pre-allocated memory. Does such a thing exist? 

Thanks

Andy

[julia-users] Re: ANN: new blog post on array indexing, iteration, and multidimensional algorithms

[Andrew Gibb]

Agreed! A very clear introduction which shows off some of the power of 
these new Array iterators. 

Thanks, Tim.

Andy

On Monday, 1 February 2016 18:55:06 UTC, Tim Holy wrote:
>
> It's come to my attention that some of the exciting capabilities of julia 
> 0.4 
> for indexing, iteration, and writing generic multidimensional algorithms 
> may 
> be under-documented. This new blog post 
>
> http://julialang.org/blog/2016/02/iteration/ 
>
> aims to provide a "gentle tutorial" illustrating how to use these 
> capabilities. 
>
> Best, 
> --Tim 
>
>

[julia-users] BinDeps Sources, when a URL doesn't have an appropriate extension

[Andrew Gibb]

Hi,

I'm trying to wrap a C library I've written. I want to use BinDeps to build 
some source. The source is on our internal gitorious git server. A .tar.gz 
of the code is available, but the URL to get that from just ends in the 
branch name. So in my code I have

provides( Sources, 
> URI("https://git0.rd.bbc.co.uk/misc/simpleexr/archive-tarball/master;) , 
> simpleexr)
>

and later

GetSources(simpleexr) 


Which throws an error:  

> LoadError: I don't know how to unpack 
> /home/andrewg/.julia/v0.4/EXRImages/deps/downloads/master
>

Is there a way to insert an intermediate step to change the name of the 
downloaded file from master to something.tar.gz? (Or indeed is there a way 
to use the filename of the file which is returned from the server, which 
does have the correct extension? As I think about, this seems a bit like a 
bug.)

I guess a bit more code context will be useful: 

provides( Sources, 
>> URI("https://git0.rd.bbc.co.uk/misc/simpleexr/archive-tarball/master;) , 
>> simpleexr)
>
>
>> prefix = joinpath(BinDeps.depsdir(simpleexr),"usr")
>
> dldir = joinpath(BinDeps.depsdir(simpleexr),"downloads")
>
> provides(SimpleBuild, 
>
> (@build_steps begin
>
> GetSources(simpleexr)
>
> @build_steps begin
>
> FileRule(joinpath(prefix,"lib","libsimpleexr.so"), 
>> @build_steps begin
>
> `./build.sh`
>
> `cp libsimpleexr.so $prefix/lib`
>
> `cp libsimpleexr.so.1 $prefix/lib`
>
> `cp libsimpleexr.so.1.0 $prefix/lib`
>
> `cp libsimpleexr.h $prefix/include`
>
> end)
>
> end 
>
> end
>
> )
>
> , simpleexr, os = :Linux)
>
>
I guess if Tim Holy sees this he'll suggest I use Images/ImageMagick to 
read an exr image. If there's a way to access the pixel values stored in 
the image before the gamma correction is applied I would gladly use it. The 
last time I looked into it, I couldn't find any mention of this in 
ImageMagick, though. 

Re: [julia-users] DataFrame type specification

[Andrew Gibb]

That worked. Thanks. 

[julia-users] DataFrame type specification

[Andrew Gibb]

I have a csv with some data. One of the columns is something I'd always 
like to be read as a string, although sometimes the value will just be 
numerals. Is there some way to specify that I want this column to be an 
AbstractString in readtable? Or perhaps some way to convert that column 
from (say) integers to strings once loaded?

Thanks

Andy

[julia-users] Creating custom METADATA

[Andrew Gibb]

I'm trying to follow the steps in the 0.4 Manual to create a custom 
METADATA.jl so that I can distribute packages around my organisation. If I 
clone JuliaLang/METADATA.jl.git into a local folder, then call Pkg.init() 
on that folder, I get the following:

INFO: Initializing package repository /Users/andrewg/.julia/v0.4
INFO: Package directory /Users/andrewg/.julia/v0.4 is already initialized.

And no META_BRANCH is created. Can anyone suggest what I'm doing wrong?

Thanks

Andy

[julia-users] Updating a single output line in IJulia

[Andrew Gibb]

Hi,

I have some loops I'd like to observe/debug by seeing the parameters 
change. In the REPL I can do
print(" $p1 $p2 \r")
flush(STDOUT)
and have my parameters updating on a line.

This doesn't seem to work in IJulia. When I try it, there is no output. I 
guess this is because this isn't STDOUT, or something like that.

Does anyone know of a nice way to do this?

Thanks

Andy

[julia-users] Getting started with documentation using Docile and Lexicon in 0.3.x

[Andrew Gibb]

Hi,

Please help me get started with this. Here' a simple Julia module, with an 
attempt at documention:

module DocThis

using Docile
@docstrings

export AThing, addfive

@doc 
This type defines a thing, which is a thing. Here's some code, declared by 
indenting:

ay = AThing(5)
bee = AThing(3.14)

So that's that. 
 -
type AThing
bee
end

@doc 
Adds five. Just like that.
 -
function addfive(x::Number)
return x + 5.
end


end #module

To using this at the REPL, I do 
using Docile, Lexicon
include(docthis.jl)
using DocThis

which I imagine should be all the initialisation I need to do. But when I 
do 

? AThing

I just get 
DataType   : AThing (constructor with 1 method)
  supertype: Any
  fields   : (:bee,)

I have tried various permutations of the documentation syntax: No macros 
(or arrows), Only @doc macros with arrows, or the version you see above. 
All of these produce the same results. What am I doing wrong?

Thanks

Adny

[julia-users] Re: Getting started with documentation using Docile and Lexicon in 0.3.x

[Andrew Gibb]

Done.[1] It turns out it was because there was no newline after the module 
end statement. The issue I've opened reflects this.

[1 ]https://github.com/MichaelHatherly/Docile.jl/issues/137

On Friday, 5 June 2015 16:04:57 UTC+1, Michael Hatherly wrote:

 Ok, could you open an issue here [1] and I'll have a closer look at what's 
 going wrong.

 [1] https://github.com/MichaelHatherly/Docile.jl/issues

 -- Mike

 On Friday, 5 June 2015 17:00:49 UTC+2, Andrew Gibb wrote:

 Mike,

 Thanks for your answer. I'm afraid your suggestions don't work. I've 
 tried modifying the LOAD_PATH in juliarc.jl, and tried the various 
 permutations of macro usage again. In every case, only the default 0.3.x 
 documentation appears when I do ?-query at the REPL. 

 From the output beneath Docile: updating package list ... It is clear 
 that DocThis is not detected by Docile at all. Perhaps there's something 
 else in the Official Package generation process upon which Docile relies?

 Andy

 On Friday, 5 June 2015 15:42:19 UTC+1, Michael Hatherly wrote:

 Docile works on whole packages rather than individual files. You just 
 need to put the file docthis.jl in the correct load path [1] so that 
 ``using DocThis`` works or else do ``require(docthis.jl)`` rather than 
 ``include(docthis.jl)``. I'll add a mention of this to the documentation 
 shortly.

 [1] 
 http://docs.julialang.org/en/latest/manual/modules/#module-file-paths

 -- Mike

 On Friday, 5 June 2015 16:25:39 UTC+2, Andrew Gibb wrote:

 Hi,

 Please help me get started with this. Here' a simple Julia module, with 
 an attempt at documention:

 module DocThis

 using Docile
 @docstrings

 export AThing, addfive

 @doc 
 This type defines a thing, which is a thing. Here's some code, declared 
 by indenting:

 ay = AThing(5)
 bee = AThing(3.14)

 So that's that. 
  -
 type AThing
 bee
 end

 @doc 
 Adds five. Just like that.
  -
 function addfive(x::Number)
 return x + 5.
 end


 end #module

 To using this at the REPL, I do 
 using Docile, Lexicon
 include(docthis.jl)
 using DocThis

 which I imagine should be all the initialisation I need to do. But when 
 I do 

 ? AThing

 I just get 
 DataType   : AThing (constructor with 1 method)
   supertype: Any
   fields   : (:bee,)

 I have tried various permutations of the documentation syntax: No 
 macros (or arrows), Only @doc macros with arrows, or the version you see 
 above. All of these produce the same results. What am I doing wrong?

 Thanks

 Adny

[julia-users] Re: Getting started with documentation using Docile and Lexicon in 0.3.x

[Andrew Gibb]

Mike,

Thanks for your answer. I'm afraid your suggestions don't work. I've tried 
modifying the LOAD_PATH in juliarc.jl, and tried the various permutations 
of macro usage again. In every case, only the default 0.3.x documentation 
appears when I do ?-query at the REPL. 

From the output beneath Docile: updating package list ... It is clear 
that DocThis is not detected by Docile at all. Perhaps there's something 
else in the Official Package generation process upon which Docile relies?

Andy

On Friday, 5 June 2015 15:42:19 UTC+1, Michael Hatherly wrote:

 Docile works on whole packages rather than individual files. You just need 
 to put the file docthis.jl in the correct load path [1] so that ``using 
 DocThis`` works or else do ``require(docthis.jl)`` rather than 
 ``include(docthis.jl)``. I'll add a mention of this to the documentation 
 shortly.

 [1] http://docs.julialang.org/en/latest/manual/modules/#module-file-paths

 -- Mike

 On Friday, 5 June 2015 16:25:39 UTC+2, Andrew Gibb wrote:

 Hi,

 Please help me get started with this. Here' a simple Julia module, with 
 an attempt at documention:

 module DocThis

 using Docile
 @docstrings

 export AThing, addfive

 @doc 
 This type defines a thing, which is a thing. Here's some code, declared 
 by indenting:

 ay = AThing(5)
 bee = AThing(3.14)

 So that's that. 
  -
 type AThing
 bee
 end

 @doc 
 Adds five. Just like that.
  -
 function addfive(x::Number)
 return x + 5.
 end


 end #module

 To using this at the REPL, I do 
 using Docile, Lexicon
 include(docthis.jl)
 using DocThis

 which I imagine should be all the initialisation I need to do. But when I 
 do 

 ? AThing

 I just get 
 DataType   : AThing (constructor with 1 method)
   supertype: Any
   fields   : (:bee,)

 I have tried various permutations of the documentation syntax: No macros 
 (or arrows), Only @doc macros with arrows, or the version you see above. 
 All of these produce the same results. What am I doing wrong?

 Thanks

 Adny

[julia-users] Inferring constructor parameters from parameters of arguments

[Andrew Gibb]

I want to create a parametric type whose parameter is inferred from the 
parameter of an argument. A toy example:

using Images

type TLPixel{T}
data::T
function TLPixel(img::Image{T})
new(img.data[1,1])
end
end

If I do this:

julia tlp = TLPixel{typeof(img.data[1,1])}(img)

This works fine. However, I would have expected the dispatcher(?) to 
realise that the parameter on the image, T, is the same as the one in the 
type declaration. But it doesn't:

julia tlp = TLPixel(img)
`TLPixel{T}` has no method matching TLPixel{T}(::Image{RGB{UfixedBase{Uint8,
8}},2,Array{RGB{UfixedBase{Uint8,8}},2}})
while loading In[4], in expression starting on line 1


Have I done something wrong here, or should I not expect this to work?

[julia-users] Type parameter describes number of items

[Andrew Gibb]

Is there a way to create a parameterised type where the parameter describes 
the number of items, ie
type Thing{N:Integer}
for i = 1:N
   a_i::Float64
   end
end

I realise one could achieve this simple example with an array, but I'm 
trying to create a type which holds scale space. My current thinking is 
this would consist of  a parameterisable number of images each with a 
parameterisable number of layers. And each image in the sequence has the 
two spatial dimensions (not the number of layers) reduced by a factor of 
two. 

I guess you cold do some tricks with array packing, but I guess I'm looking 
for something more elegant. Is there any way to use the type parameter to 
indicate a number of elements in this way?

Andy

[julia-users] New Images.jl - struggling

[Andrew Gibb]

I'm having difficulty getting to grips with the new image representations 
in the reworked Images.jl. I think I've got some of the basics down. But 
now I'm trying to visualise a spectrum, and I'm stumped.

What's the correct way to create an array/image of Float64s from an 
array/image of Gray{Ufixed8} (So that fft() works), and vice versa (so I 
can visualize the spectrum)?

Thanks.

[julia-users] Problem loading Images module

[Andrew Gibb]

Hi,

I get the following error:

julia using Images
ERROR: syntax: invalid assignment location
 in include at ./boot.jl:245
 in include_from_node1 at ./loading.jl:128
 in include at ./boot.jl:245
 in include_from_node1 at ./loading.jl:128
 in reload_path at loading.jl:152
 in _require at loading.jl:67
 in require at loading.jl:51
while loading /Users/andrewg/.julia/v0.3/Images/src/ioformats/OSXnative.jl, 
in expression starting on line 8
while loading /Users/andrewg/.julia/v0.3/Images/src/Images.jl, in 
expression starting on line 39

having just done 
$ make cleanall
$ make -j 4 USE_SYSTEM_BLAS=1

I got the same results without the USE_SYSTEM_BLAS flag. I've tried the 
advice from the Images module readme to comment out a line from 
Images/src/io.jl, which appears to have no effect on this error. The OS, my 
julia source (master branch) and homebrew imagemagick etc are all up to 
date. 

Is there something I can do to remedy this, or shall I file an issue?

I also noticed that the error message I've copied above only appears on the 
first invocation of using Images at the REPL. further invocations fail 
silently. Is this intended behaviour? 

Thanks

Andy

[julia-users] Re: Problem loading Images module

[Andrew Gibb]

I see. Yes, that fixed it. But I learned quite a bit about github and julia 
in the meantime. :)
I've noted the fix in the github issue. 

On Wednesday, 23 July 2014 12:32:29 UTC+1, ron.s...@gmail.com wrote:

 Yes, that's my fault, I should have run the tests one last time.  I fixed 
 it and tagged a new version (0.2.47) a few ours ago, hoping no one would 
 notice.  A `Pkg.update()` should fix it for you.

[julia-users] Implementation of Moment Invariants?

[Andrew Gibb]

I'm hoping to play around with Geometric Moment Invariants, as (greyscale) 
image feature descriptors. I get the impression that these might be part of 
some stats package, but I'm coming at this from the machine vision side, 
and so don't really know where to look. A few simple google searches don't 
turn up anything that looks like what I'm looking for. Has anyone made an 
implementation in Julia yet?

Thanks

Andy

[julia-users] Re: GSOC 3D Visualizations plotting API - Make a wish!

[Andrew Gibb]

I'm believe I'm working in a relatively niche area, but I'm going to throw 
my request in anyway :)

I often work with image sequences (from a still or video camera, but 
nothing more exotic than broadcast cameras) which are to be displayed at 
video rate (25/50/...Hz), somewhere on a texture in 3D space, after having 
had some analysis applied to them. Having the ability to apply video 
textures which were the output of some julia analysis onto a 3D object 
whose vertices were also the output of some analysis would be really cool. 

Andy

[julia-users] Broken link in the docs

[Andrew Gibb]

Apologies if this is the wrong place to post this.

The link on this page:
http://docs.julialang.org/en/release-0.1/manual/getting-started/

With the text
Tutorial for Homer Reid’s numerical analysis class
is broken. At a guess, it should point here:

http://homerreid.dyndns.org/teaching/18.330/JuliaProgramming.shtml

Andy

[julia-users] Re: Broken link in the docs

[Andrew Gibb]

Thanks for pointing that out Ivar. I'm not sure how I managed to get to the 
0.1 docs. I didn't have the tab open *that* long.

Currently, http://docs.julialang.org points to 
http://docs.julialang.org/en/release-0.2/ which seems sensible, as it's the 
current release. I see the link is indeed fixed in the latest docs. I guess 
since the release of 0.3 is fairly imminent, a fix to the website will be 
coming. 

Andy

On Thursday, 1 May 2014 10:15:40 UTC+1, Ivar Nesje wrote:

 julia-users is a perfect place to start, if you don't know where to report 
 any kind of Julia issue. For simple errors in the documentation, the 
 appropriate fix is to submit a Pull Request on github that changes the 
 appropriate files in the doc/ directory. 

 This particular issue has been fixed in the latest 
 documentationhttp://docs.julialang.org/en/latest/manual/getting-started/#resources.
  
 I don't know how to update the older docs, but it might work to submit a 
 pull request against the 0.1-release branch. 0.1 has been obsolete half a 
 year, so I don't think this is a high priority. Unfortunately links and 
 search often points to the old versions, so we should probably consider 
 adding a banner on top of every page to make people aware that they are 
 using the docs for a very old Julia version.

 Ivar

 kl. 09:51:36 UTC+2 torsdag 1. mai 2014 skrev Andrew Gibb følgende:

 Apologies if this is the wrong place to post this. 

 The link on this page: 
 http://docs.julialang.org/en/release-0.1/manual/getting-started/ 

 With the text 
 Tutorial for Homer Reid’s numerical analysis class 
 is broken. At a guess, it should point here: 

 http://homerreid.dyndns.org/teaching/18.330/JuliaProgramming.shtml 

 Andy