Re: Optimize my code =)
On Tuesday, 18 February 2014 at 07:50:23 UTC, bearophile wrote: Stanislav Blinov: http://dpaste.dzfl.pl/9d7feeab59f6 Few small things should still be improved, but it's an improvement. Perhaps it needs to use a reference counting from Phobos. COW for matrices? Aw, come on... :) LDC yields roughly the same times. This is surprising. To me as well. I haven't yet tried to dig deep though.
Re: Question about CPU caches and D context pointers
None of your buffers are on stack in both examples. As those are dynamic arrays you only get pointer + length as value and data itself resides on heap in some unknown location. It can be in cache too, of course, if it has been used actively, but it can't be verified based on this simple snippet. To get best cache friendliness one may use dynamic-size structs akin to C but, of course, this does not go well with necessity to grow the buffer dynamically for given instance. Also note that your first snippet uses ~= operator which will cause new heap allocations invalidating any old cache.
Re: Optimize my code =)
On Tuesday, 18 February 2014 at 07:45:18 UTC, bearophile wrote: Stanislav Blinov: that explicit ctor for Dimension is completely unnecessary too. I like a constructor(s) like that because it catches bugs like: auto d = Dimension(5); Hmmm... yeah, ok, not completely unnecessary :)
Importing text file, path not found
I am testing with the import expression. I am using the -J flag
while compiling.
dmd app.d -J/home/user/include
void main(){
auto test = json.parseJSON(
import(/home/user/include/test.json) );
}
1. Because I am giving the full path of that file to be imported.
But compiler is complaining about that it cannot find the file.
If I remove the path, and leave the file name only, it works. Am
I doing something wrong, or bug?
2. Why do I need to tell compiler where to look at if I am going
to tell where the file is already? Shouldn't it be like Hey
compiler, if you cannot while the file, look at those places,
and I shouldn't need to use J flag if not necessary?
Re: foreach/iota countdown
On Tuesday, 18 February 2014 at 05:21:24 UTC, Brian Schott wrote:
On Monday, 17 February 2014 at 19:22:38 UTC, simendsjo wrote:
Should the following two uses be a compile-time error?
foreach(i; 10 .. 0) // Never executes
foreach(i; iota(10, 0)) // .. neither does this
I would like the second to either be a compile-time error or
automagically use a negative step.
So we need to use a negative step in iota() or use a for loop
foreach(i; iota(10, 0, -1)) // as expected
I just added this check to DScanner:
-
import std.stdio;
void main(string[] args)
{
auto x = args[3 .. 2];
foreach (i; 20 .. 10)
{
}
}
-
/home/alaran/tmp/test.d(5:16)[warn]: 3 is larger than 2. This
slice is likely incorrect.
/home/alaran/tmp/test.d(6:22)[warn]: 20 is larger than 10. Did
you mean to use 'foreach_reverse( ... ; 10 .. 20)'?
Isn't foreach_reverse being deprecated?
Re: Importing text file, path not found
On Tuesday, 18 February 2014 at 08:45:16 UTC, Tolga Cakiroglu
(tcak) wrote:
I am testing with the import expression. I am using the -J
flag while compiling.
dmd app.d -J/home/user/include
void main(){
auto test = json.parseJSON(
import(/home/user/include/test.json) );
}
1. Because I am giving the full path of that file to be
imported. But compiler is complaining about that it cannot find
the file. If I remove the path, and leave the file name only,
it works. Am I doing something wrong, or bug?
2. Why do I need to tell compiler where to look at if I am
going to tell where the file is already? Shouldn't it be like
Hey compiler, if you cannot while the file, look at those
places, and I shouldn't need to use J flag if not necessary?
- Grammar issues -
1. Because I am giving the full path of that file to be
imported, compiler is complaining about that it cannot find
the file. If I remove the path, and leave the file name only,
it works. Am I doing something wrong, or bug?
2. Why do I need to tell compiler where to look at if I am
going to tell where the file is already? Shouldn't it be like
Hey compiler, if you cannot find the file, look at those
places, and I shouldn't need to use J flag if not necessary?
Re: Optimize my code =)
Stanislav Blinov: allocationTest ... Time required: 1 sec, 112 ms, 827 μs, and 3 hnsecs multiplicationTest ... Time required: 1 sec, 234 ms, 417 μs, and 8 hnsecs Physics teaches us that those experimental measures are expressed with a excessive precision. For such benchmarks it's more wise to write 1.11 seconds. Bye, bearophile
Re: Optimize my code =)
Stanislav Blinov: LDC yields roughly the same times. This is surprising. To me as well. I haven't yet tried to dig deep though. I have compiled your code with (a single module, 32 bit Windows): dmd -wi -vcolumns -O -release -inline -noboundscheck matrix3.d ldmd2 -wi -O -release -inline -noboundscheck matrix3.d DMD: multiplicationTest ... Time required: 4 secs, 665 ms, 452 ╬╝s, and 2 hnsecs LDC2: multiplicationTest ... Time required: 2 secs, 522 ms, and 747 ╬╝s Bye, bearophile
Re: Optimize my code =)
On Tuesday, 18 February 2014 at 08:50:23 UTC, bearophile wrote: Stanislav Blinov: LDC yields roughly the same times. This is surprising. To me as well. I haven't yet tried to dig deep though. I have compiled your code with (a single module, 32 bit Windows): dmd -wi -vcolumns -O -release -inline -noboundscheck matrix3.d ldmd2 -wi -O -release -inline -noboundscheck matrix3.d DMD: multiplicationTest ... Time required: 4 secs, 665 ms, 452 ╬╝s, and 2 hnsecs LDC2: multiplicationTest ... Time required: 2 secs, 522 ms, and 747 ╬╝s Interesting. For me (on 64 bit) multiplicationTest is in the same league for DMD and LDC. (I'm still using dmd 2.064.2 as my main dmd install btw). But what is up with those first and last tests in LDC?.. $ rdmd -wi -O -release -inline -noboundscheck main.d allocationTest ... Time required: 1 sec, 165 ms, 766 μs, and 1 hnsec multiplicationTest ... Time required: 1 sec, 232 ms, 287 μs, and 4 hnsecs toStringTest ... Time required: 997 ms, 217 μs, and 1 hnsec transposeTest ... Time required: 859 ms, 152 μs, and 5 hnsecs scalarMultiplicationTest ... Time required: 105 ms, 366 μs, and 5 hnsecs matrixAddSubTest ... Time required: 241 ms, 705 μs, and 8 hnsecs matrixEqualsTest ... Time required: 243 ms, 534 μs, and 8 hnsecs identityMatrixTest ... Time required: 260 ms, 411 μs, and 4 hnsec $ ldmd2 -wi -O -release -inline -noboundscheck main.d neolab/core/dimension.d neolab/core/matrix.d -ofmain-ldc main-ldc allocationTest ... Time required: 2 hnsecs (o_O) multiplicationTest ... Time required: 1 sec, 138 ms, 628 μs, and 2 hnsecs toStringTest ... Time required: 704 ms, 937 μs, and 5 hnsecs transposeTest ... Time required: 859 ms, 413 μs, and 5 hnsecs scalarMultiplicationTest ... Time required: 103 ms, 250 μs, and 2 hnsecs matrixAddSubTest ... Time required: 226 ms, 955 μs, and 3 hnsecs matrixEqualsTest ... Time required: 470 ms and 186 μs identityMatrixTest ... Time required: 4 hnsecs (o_O)
Re: Importing text file, path not found
Tolga Cakiroglu (tcak): 1. Because I am giving the full path of that file to be imported, compiler is complaining about that it cannot find the file. If I remove the path, and leave the file name only, it works. Am I doing something wrong, or bug? 2. Why do I need to tell compiler where to look at if I am going to tell where the file is already? Shouldn't it be like Hey compiler, if you cannot find the file, look at those places, and I shouldn't need to use J flag if not necessary? It seems things are working as designed. The J flag is meant for security. Bye, bearophile
Re: Importing text file, path not found
On Tuesday, 18 February 2014 at 08:45:16 UTC, Tolga Cakiroglu (tcak) wrote: 1. Because I am giving the full path of that file to be imported. But compiler is complaining about that it cannot find the file. If I remove the path, and leave the file name only, it works. Am I doing something wrong, or bug? 2. Why do I need to tell compiler where to look at if I am going to tell where the file is already? Shouldn't it be like Hey compiler, if you cannot while the file, look at those places, and I shouldn't need to use J flag if not necessary? It is a matter of security I think. By restricting imports to only explicitly allowed locations and prohibiting fully-qualified paths dmd guarantees you that compiled program won't access anything outside of that sandbox. That way compilation process stays relatively safe.
Re: std.range.equal or == in isPalindrome
Per Nordlöw: Why isn't equality == operator used here instead? In some cases I'd even like to use ~ instead of chain(). Bye, bearophile
Re: std.range.equal or == in isPalindrome
On Tuesday, 18 February 2014 at 09:31:55 UTC, Per Nordlöw wrote:
I'm curious to why we need std.range.equal in cases such as
bool isPalindrome(Range)(in Range range) if
(isBidirectionalRange!Range)
{
return range.retro.equal(range);
}
Why isn't equality == operator used here instead?
/Per
1) opEquals cannot be a free function
2) there's no telling what opEquals does if Range defines it
IOW, equal() has a defined by-element-comparison semantics, while
opEquals doesn't.
Re: std.range.equal or == in isPalindrome
On Tuesday, 18 February 2014 at 09:34:41 UTC, bearophile wrote: In some cases I'd even like to use ~ instead of chain(). Range interface should be minimal. Don't forget that user types can provide range interface and still benefit from operator overloading for different purposes.
Interface file is generated wrong
I have written a module as below:
file: lib.d
import core.sys.posix.dlfcn;
private static this(){}
private static ~this(){}
public shared class Apps{
}
---
This code is compiled with -H flag to generate an interface
file. Generated interface file is below:
file: lib.di
// D import file generated from 'lib.d'
import core.sys.posix.dlfcn;
private static this();
private
public shared class Apps
{
}
---
Compiler is adding a redundant private keyword before the
class, and static destructor function is not there any more. Thus
compiler is giving Redundant protection attribute error.
Bug? (I don't know if I should immediately file a bug when I
think it is a bug without asking what other people thinks.)
Re: Importing text file, path not found
On Tuesday, 18 February 2014 at 09:24:50 UTC, Dicebot wrote: On Tuesday, 18 February 2014 at 08:45:16 UTC, Tolga Cakiroglu (tcak) wrote: 1. Because I am giving the full path of that file to be imported. But compiler is complaining about that it cannot find the file. If I remove the path, and leave the file name only, it works. Am I doing something wrong, or bug? 2. Why do I need to tell compiler where to look at if I am going to tell where the file is already? Shouldn't it be like Hey compiler, if you cannot while the file, look at those places, and I shouldn't need to use J flag if not necessary? It is a matter of security I think. By restricting imports to only explicitly allowed locations and prohibiting fully-qualified paths dmd guarantees you that compiled program won't access anything outside of that sandbox. That way compilation process stays relatively safe. Hmm. Should I understand the sandbox as if I am going to be compiling someone else's code, only looking at -J flags will be enough to make sure it is not using any of my private files?
Re: Interface file is generated wrong
On Tuesday, 18 February 2014 at 10:07:37 UTC, Tolga Cakiroglu (tcak) wrote: Bug? Yup. (I don't know if I should immediately file a bug when I think it is a bug without asking what other people thinks.) 1) Do a seach in bugzilla 2) If the search doesn't show anything similar, file it 3) If it's not a bug, it'll be closed as such That's it :)
Re: Importing text file, path not found
On Tuesday, 18 February 2014 at 10:10:14 UTC, Tolga Cakiroglu wrote: Hmm. Should I understand the sandbox as if I am going to be compiling someone else's code, only looking at -J flags will be enough to make sure it is not using any of my private files? It is the intention. I can't guarantee there are no bugs that break that assumption though :)
Re: Optimize my code =)
...And if I define opEquals as it was made by Robin, i.e. like
this:
bool opEquals(ref const Matrix other) const pure nothrow {
version (all) {
if (dim != other.dim) return false;
foreach(immutable i, const ref e; data)
if (e != other.data[i])
return false;
return true;
} else {
return (dim == other.dim) (data[] == other.data[]);
}
}
then the relevant benchmark on LDC flattens near zero time too x.x
Re: foreach/iota countdown
/home/alaran/tmp/test.d(5:16)[warn]: 3 is larger than 2. This
slice is likely incorrect.
/home/alaran/tmp/test.d(6:22)[warn]: 20 is larger than 10. Did
you mean to use 'foreach_reverse( ... ; 10 .. 20)'?
Isn't foreach_reverse being deprecated?
Oh. If so, what would be the right way to iterate backwards?
The usual for (*;*;*) is too repetitive and error-prone:
nothing is going to catch some for (int i = 19; i = 10; j--)
errors or the like. Using ranges, such as iota and retro,
currently results in a *massive* slowdown for DMD.
As a crude proof for the last statement, below are my local
timings for DMD 2.064.2 on Win32 using dmd -O -release -inline
-noboundscheck to compile.
Example 1 (0.38 sec):
void main () {foreach (i; 0..1_000_000_000) {}}
Example 2 (0.39 sec):
void main () {for (int i = 0; i 1_000_000_000; i++) {}}
Example 3 (2.03 sec):
import std.range;
void main () {foreach (i; iota (1_000_000_000)) {}}
Unless simple things like example 3 run on par with the first
two, foreach on ranges - or, in that regard, UFCS
functional-style range chains without even a foreach - are just
plain unacceptable in bottlenecks. LDC is able to handle simple
cases like this, but introducing a compiler dependency just
because of this? That would also be unfortunate.
Ivan Kazmenko.
Re: foreach/iota countdown
Sergei Nosov: Isn't foreach_reverse being deprecated? The idea was discussed a little, but it's not deprecated, and probably it will not be deprecated. Bye, bearophile
Re: Interface file is generated wrong
On Tuesday, 18 February 2014 at 10:15:51 UTC, Stanislav Blinov wrote: On Tuesday, 18 February 2014 at 10:07:37 UTC, Tolga Cakiroglu (tcak) wrote: Bug? Yup. (I don't know if I should immediately file a bug when I think it is a bug without asking what other people thinks.) 1) Do a seach in bugzilla 2) If the search doesn't show anything similar, file it 3) If it's not a bug, it'll be closed as such That's it :) Thanks. Well, by putting that destructor to the end of lib.d, dmd has ended with segmentation error. dmd -c lib.d -H -fPIC -release -inline gcc --shared lib.o -o lib.so dmd app.d -L-ldl -release -O -inline lib.di(83): Error: declaration expected following attribute, not EOF make: *** [app] Segmentation fault (core dumped) It looks like a big bug.
Re: std.range.equal or == in isPalindrome
Stanislav Blinov: Range interface should be minimal. I agree. But I didn't mean to ask for that operator in the Range protocol. I think some ranges should define a ~ operator. It's easy to write a chainable trait. I did that for my nonstandard D1 library. Bye, bearophile
Re: 64 bit size_t
Rather than change it to int/ulong, just change it to 'size_t len = parent.children.length+1' (or auto instead of size_t). This way it's proper for both 32-bit and 64-bit and you don't need to worry about architecture. If you do need a signed version, you can use ptrdiff_t. Yup, that's what I did when my head returned to its usual postion ;=)
Re: std.range.equal or == in isPalindrome
On Tuesday, 18 February 2014 at 10:47:33 UTC, bearophile wrote: Stanislav Blinov: Range interface should be minimal. I agree. But I didn't mean to ask for that operator in the Range protocol. I think some ranges should define a ~ operator. It's easy to write a chainable trait. I did that for my nonstandard D1 library. Bye, bearophile Could you post the isChainable trait? I'm curious :) /Per
Re: std.range.equal or == in isPalindrome
On Tuesday, 18 February 2014 at 11:39:12 UTC, Per Nordlöw wrote: On Tuesday, 18 February 2014 at 10:47:33 UTC, bearophile wrote: Stanislav Blinov: Range interface should be minimal. I agree. But I didn't mean to ask for that operator in the Range protocol. I think some ranges should define a ~ operator. It's easy to write a chainable trait. I did that for my nonstandard D1 library. Bye, bearophile Could you post the isChainable trait? I'm curious :) /Per Ahh, I guess you mean http://forum.dlang.org/thread/bug-604...@http.d.puremagic.com%2Fissues%2F /Per
[video tutorial] Refactoring the number guessing game
http://youtu.be/yhK7zvnWmiU
Re: [video tutorial] Implementing a simple number guessing game
On Tuesday, 18 February 2014 at 07:19:05 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 07:06:11 UTC, Suliman wrote: On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo Thanks! But could you use bigger fonts and more contrast color scheme for better view in next videos? I'll increase the font size, but I think 30 lines on the screen would be too big (it's almost there in that video). The contrast is another issue.. I have tweaked urxvt, tmux and vim in order to get these colors. Trying to change just the colorscheme in vim doesn't give the expected results I'm afraid. You could always just alter the contrast/color-balance in the video.
Re: [video tutorial] Implementing a simple number guessing game
On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo did i mention i loved your tutorials? keep up the great work.
Re: [video tutorial] Implementing a simple number guessing game
On Tuesday, 18 February 2014 at 13:39:38 UTC, John Colvin wrote: On Tuesday, 18 February 2014 at 07:19:05 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 07:06:11 UTC, Suliman wrote: On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo Thanks! But could you use bigger fonts and more contrast color scheme for better view in next videos? I'll increase the font size, but I think 30 lines on the screen would be too big (it's almost there in that video). The contrast is another issue.. I have tweaked urxvt, tmux and vim in order to get these colors. Trying to change just the colorscheme in vim doesn't give the expected results I'm afraid. You could always just alter the contrast/color-balance in the video. I've never done any video editing, so I have no idea how. I tried pressing around on the YouTube enhance video settings, but it looks like an LSD trip no matter what I do.
Re: [video tutorial] Implementing a simple number guessing game
On Tuesday, 18 February 2014 at 13:46:11 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 13:39:38 UTC, John Colvin wrote: On Tuesday, 18 February 2014 at 07:19:05 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 07:06:11 UTC, Suliman wrote: On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo Thanks! But could you use bigger fonts and more contrast color scheme for better view in next videos? I'll increase the font size, but I think 30 lines on the screen would be too big (it's almost there in that video). The contrast is another issue.. I have tweaked urxvt, tmux and vim in order to get these colors. Trying to change just the colorscheme in vim doesn't give the expected results I'm afraid. You could always just alter the contrast/color-balance in the video. I've never done any video editing, so I have no idea how. I tried pressing around on the YouTube enhance video settings, but it looks like an LSD trip no matter what I do. But is the contrast really that bad? I find my settings easy on the eyes. Clown colors makes me dizzy.
Re: [video tutorial] Implementing a simple number guessing game
On Tuesday, 18 February 2014 at 13:47:22 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 13:46:11 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 13:39:38 UTC, John Colvin wrote: On Tuesday, 18 February 2014 at 07:19:05 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 07:06:11 UTC, Suliman wrote: On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo Thanks! But could you use bigger fonts and more contrast color scheme for better view in next videos? I'll increase the font size, but I think 30 lines on the screen would be too big (it's almost there in that video). The contrast is another issue.. I have tweaked urxvt, tmux and vim in order to get these colors. Trying to change just the colorscheme in vim doesn't give the expected results I'm afraid. You could always just alter the contrast/color-balance in the video. I've never done any video editing, so I have no idea how. I tried pressing around on the YouTube enhance video settings, but it looks like an LSD trip no matter what I do. But is the contrast really that bad? I find my settings easy on the eyes. Clown colors makes me dizzy. It's fine in my opinion, but it's a matter of taste.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:16:27 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading. Combining efforts is always good, but I'm not sure if creating video tutorials can keep my interest for very long. It also sounds like you have plans to make this a lot more professional: planning content and editing videos. I just press record and upload :/
Re: [video tutorial] Implementing a simple number guessing game
On Tuesday, 18 February 2014 at 14:04:50 UTC, John Colvin wrote: On Tuesday, 18 February 2014 at 13:47:22 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 13:46:11 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 13:39:38 UTC, John Colvin wrote: On Tuesday, 18 February 2014 at 07:19:05 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 07:06:11 UTC, Suliman wrote: On Monday, 17 February 2014 at 13:35:34 UTC, simendsjo wrote: http://youtu.be/2Co65Ftxfdo Thanks! But could you use bigger fonts and more contrast color scheme for better view in next videos? I'll increase the font size, but I think 30 lines on the screen would be too big (it's almost there in that video). The contrast is another issue.. I have tweaked urxvt, tmux and vim in order to get these colors. Trying to change just the colorscheme in vim doesn't give the expected results I'm afraid. You could always just alter the contrast/color-balance in the video. I've never done any video editing, so I have no idea how. I tried pressing around on the YouTube enhance video settings, but it looks like an LSD trip no matter what I do. But is the contrast really that bad? I find my settings easy on the eyes. Clown colors makes me dizzy. It's fine in my opinion, but it's a matter of taste. I'll leave it as-is. If more people complain, I'll google around and try to fix them.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:19:47 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:16:27 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading. Combining efforts is always good, but I'm not sure if creating video tutorials can keep my interest for very long. It also sounds like you have plans to make this a lot more professional: planning content and editing videos. I just press record and upload :/ Don't worry about that. We can sort out making things higher quality as series goes :)
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:20:44 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:19:47 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:16:27 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading. Combining efforts is always good, but I'm not sure if creating video tutorials can keep my interest for very long. It also sounds like you have plans to make this a lot more professional: planning content and editing videos. I just press record and upload :/ Don't worry about that. We can sort out making things higher quality as series goes :) Have you written a plan/schedule for the videos somewhere? And I cannot see a way to move the videos to other users in YouTube.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:25:33 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:20:44 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:19:47 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:16:27 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading. Combining efforts is always good, but I'm not sure if creating video tutorials can keep my interest for very long. It also sounds like you have plans to make this a lot more professional: planning content and editing videos. I just press record and upload :/ Don't worry about that. We can sort out making things higher quality as series goes :) Have you written a plan/schedule for the videos somewhere? And I cannot see a way to move the videos to other users in YouTube. I haven't yet made a plan. Its mostly in my head at the current point in time. However we can do something, perhaps on a repo. You don't need to move them. You can add any video to a playlist, given a url.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:36:17 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:27:19 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:25:33 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:20:44 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:19:47 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:16:27 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 13:00:09 UTC, simendsjo wrote: http://youtu.be/yhK7zvnWmiU Would you be interested in doing a Lets make series on ApplyYourDLang? As this falls under this heading. Combining efforts is always good, but I'm not sure if creating video tutorials can keep my interest for very long. It also sounds like you have plans to make this a lot more professional: planning content and editing videos. I just press record and upload :/ Don't worry about that. We can sort out making things higher quality as series goes :) Have you written a plan/schedule for the videos somewhere? And I cannot see a way to move the videos to other users in YouTube. I haven't yet made a plan. Its mostly in my head at the current point in time. However we can do something, perhaps on a repo. You don't need to move them. You can add any video to a playlist, given a url. I'll be more than happy to place the videos elsewhere, but I don't want to commit to a large ongoing project as I'm pretty busy with school too. Posting your ideas somewhere would be nice though. I've posted the code so far on bitbucket, but moving to another repo (github?) and changing links in the videos is trivial if you think my videos would fit your playlist - even though they're nothing more than live coding videos :) Oh, and I thought of making perhaps 3 more videos: std.getopt, splitting a project into subprojects with dub, and another vibe.d demo. All just as extensions to the simple number guessing game. We'll see if I ever get this far.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:36:17 UTC, simendsjo wrote: I'll be more than happy to place the videos elsewhere, but I don't want to commit to a large ongoing project as I'm pretty busy with school too. Posting your ideas somewhere would be nice though. What I was thinking was, for a smaller set of projects grouped together. In one series. This way you're not committed. I've posted the code so far on bitbucket, but moving to another repo (github?) and changing links in the videos is trivial if you think my videos would fit your playlist - even though they're nothing more than live coding videos :) Seeing how others develop while learning is a very important thing while learning. So yes it very much fits. I've sent you an invite to manage it. You'll be able to do e.g. upload video or add playlists ext. As well as work on the Google+ page [0]. [0] https://plus.google.com/u/0/b/115883286620259563734/
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:42:22 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:36:17 UTC, simendsjo wrote: I'll be more than happy to place the videos elsewhere, but I don't want to commit to a large ongoing project as I'm pretty busy with school too. Posting your ideas somewhere would be nice though. What I was thinking was, for a smaller set of projects grouped together. In one series. This way you're not committed. I've posted the code so far on bitbucket, but moving to another repo (github?) and changing links in the videos is trivial if you think my videos would fit your playlist - even though they're nothing more than live coding videos :) Seeing how others develop while learning is a very important thing while learning. So yes it very much fits. I've sent you an invite to manage it. You'll be able to do e.g. upload video or add playlists ext. As well as work on the Google+ page [0]. [0] https://plus.google.com/u/0/b/115883286620259563734/ Not sure I'm able to connect.. When pressing the link, it turns up for my G+ user. If I log in as the YouTube user and go to that link, I still turn up as the G+ user. Why on earth won't Google let me merge the accounts?...
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:48:53 UTC, simendsjo wrote: Not sure I'm able to connect.. When pressing the link, it turns up for my G+ user. If I log in as the YouTube user and go to that link, I still turn up as the G+ user. Why on earth won't Google let me merge the accounts?... I don't know. But you do need to accept the manager invite. I sent it to the one you subscribed to the channel as. From there you can switch to it if you want.
Re: Interface file is generated wrong
On Tue, 18 Feb 2014 05:47:41 -0500, Tolga Cakiroglu t...@pcak.com wrote: On Tuesday, 18 February 2014 at 10:15:51 UTC, Stanislav Blinov wrote: On Tuesday, 18 February 2014 at 10:07:37 UTC, Tolga Cakiroglu (tcak) wrote: Bug? Yup. (I don't know if I should immediately file a bug when I think it is a bug without asking what other people thinks.) 1) Do a seach in bugzilla 2) If the search doesn't show anything similar, file it 3) If it's not a bug, it'll be closed as such That's it :) Thanks. Well, by putting that destructor to the end of lib.d, dmd has ended with segmentation error. dmd -c lib.d -H -fPIC -release -inline gcc --shared lib.o -o lib.so dmd app.d -L-ldl -release -O -inline lib.di(83): Error: declaration expected following attribute, not EOF make: *** [app] Segmentation fault (core dumped) It looks like a big bug. Please mark said bug with the tag ice. This marks it as a bug which crashes the compiler, and it will get a higher priority. -Steve
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 14:51:28 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:48:53 UTC, simendsjo wrote: Not sure I'm able to connect.. When pressing the link, it turns up for my G+ user. If I log in as the YouTube user and go to that link, I still turn up as the G+ user. Why on earth won't Google let me merge the accounts?... I don't know. But you do need to accept the manager invite. I sent it to the one you subscribed to the channel as. From there you can switch to it if you want. Ah, I'm in. You'll have to dictate what to do next. Maybe we should continue this by mail? My gmail is simendsjo.
Re: [video tutorial] Refactoring the number guessing game
On Tuesday, 18 February 2014 at 15:14:09 UTC, simendsjo wrote: On Tuesday, 18 February 2014 at 14:51:28 UTC, Rikki Cattermole wrote: On Tuesday, 18 February 2014 at 14:48:53 UTC, simendsjo wrote: Not sure I'm able to connect.. When pressing the link, it turns up for my G+ user. If I log in as the YouTube user and go to that link, I still turn up as the G+ user. Why on earth won't Google let me merge the accounts?... I don't know. But you do need to accept the manager invite. I sent it to the one you subscribed to the channel as. From there you can switch to it if you want. Ah, I'm in. You'll have to dictate what to do next. Maybe we should continue this by mail? My gmail is simendsjo. Just sent you a message via hangouts on G+. Will be easier as its IM. If anybody wants to join in, give us a yell.
Re: Optimize my code =)
On Tuesday, 18 February 2014 at 09:05:33 UTC, Stanislav Blinov wrote: allocationTest ... Time required: 2 hnsecs (o_O) identityMatrixTest ... Time required: 4 hnsecs (o_O) LDC is probably detecting that you're never actually using the results of the operation and that none of the steps have side-effects, so it's optimizing the call out. One way of avoiding this is to do something like writeln the result of an operation.
Re: std.range.chunk without length
On Thursday, 13 February 2014 at 17:41:37 UTC, monarch_dodra wrote: On Thursday, 13 February 2014 at 14:45:44 UTC, bearophile wrote: Stephan Schiffels: It would be actually easy to implement chunks without the save function, by using an internal buffer, which would however make this algorithm's memory burden linear in the chunk size. Would that be acceptable? I think it's acceptable. But perhaps you need to add one more optional argument for the buffer :-) Bye, bearophile Users andralex: https://github.com/D-Programming-Language/phobos/pull/1186 And quickfur: https://github.com/D-Programming-Language/phobos/pull/1453 Have submitted different algorithms for a similar problem: Basically, bu being 2-dimensional lazy (each subrange is itself a lazy range). However, both come with their own pitfalls. Andrei's still requires forward ranges. quickfur's doesn't, and, arguably, has a simpler design. However, if I remember correctly, it is also less efficient (it does double work). Implementing Quickfur's solution in Chunks for input ranges only could be a good idea. It *is* extra work, more code, more code to cover (that is difficult to cover). I'm not sure we have the man power to support such complexity: I was able to make chunks work with forward ranges, but I still haven't even fixed Splitter yet! I think that should take precedence. Yeah, nevermind, I won't do it. I realised that you had good reasons to require a ForwardRange. Chunking really needs some sort of save implemented. And what I had in mind to make it work on File.byLine with a buffer is actually a hack that effectively adds save functionality to the InputRange… so I agree it's logically not reasonable to do it here. Thanks anyway. Stephan
Re: Interface file is generated wrong
On Tuesday, 18 February 2014 at 15:02:38 UTC, Steven Schveighoffer wrote: On Tue, 18 Feb 2014 05:47:41 -0500, Tolga Cakiroglu t...@pcak.com wrote: On Tuesday, 18 February 2014 at 10:15:51 UTC, Stanislav Blinov wrote: On Tuesday, 18 February 2014 at 10:07:37 UTC, Tolga Cakiroglu (tcak) wrote: Bug? Yup. (I don't know if I should immediately file a bug when I think it is a bug without asking what other people thinks.) 1) Do a seach in bugzilla 2) If the search doesn't show anything similar, file it 3) If it's not a bug, it'll be closed as such That's it :) Thanks. Well, by putting that destructor to the end of lib.d, dmd has ended with segmentation error. dmd -c lib.d -H -fPIC -release -inline gcc --shared lib.o -o lib.so dmd app.d -L-ldl -release -O -inline lib.di(83): Error: declaration expected following attribute, not EOF make: *** [app] Segmentation fault (core dumped) It looks like a big bug. Please mark said bug with the tag ice. This marks it as a bug which crashes the compiler, and it will get a higher priority. -Steve Okay. Done. Issue 12192 - Wrong interface file content generated that crashes compiler
trace GC work
Hi,
Is it possible to trace GC allocation calls to determine times of
program death and have some stats?
So i want the following information:
- garbage collection starts at {time}
- garbage collection stops at {time}
- (optionally) gc took {time}, collected {size} bytes
thanks.
Re: Question about CPU caches and D context pointers
On Tuesday, 18 February 2014 at 08:11:04 UTC, Dicebot wrote:
None of your buffers are on stack in both examples. As those
are dynamic arrays you only get pointer + length as value and
data itself resides on heap in some unknown location.
That.
struct S {}
class C {}
S[] s1; // fat pointer to an array of structs
S[2] s2; // array of two structs, plus a length?
C[] c1; // fat pointer to an array of pointers
C[2] c2; // array of two pointers, plus a length?
I tested some prime sieves both in C++ and D. They worked fastest
with dynamic arrays with a size matching the L1 cache. I presume
the instructions are located elsewhere in the CPU.
Re: Question about CPU caches and D context pointers
On Tuesday, 18 February 2014 at 18:13:24 UTC, Casper Færgemand wrote: S[2] s2; // array of two structs, plus a length? Storing length is not needed for static arrays because it is known, well, statically. I tested some prime sieves both in C++ and D. They worked fastest with dynamic arrays with a size matching the L1 cache. I presume the instructions are located elsewhere in the CPU. Yes, instruction cache is completely separated from data cache.
What learning resources are available?
Hi everyone - I'm a D newbie with a very strong C++ background looking to get started. I've read The D Programming Language a couple of times now, but I've heard rumblings at several points in time from several people that some if its contents are now out of date or no longer reflect best practices. What would be the best way to bridge the learning gap between TDPL's publication and now? What other resources would be most useful in establishing a working knowledge of idiomatic D? What's the best way to stay informed about such changes in the future? (Is there a mailing list, or should I just be reading dmd changelogs?) Thanks in advance!
Re: What learning resources are available?
On Tuesday, 18 February 2014 at 19:17:55 UTC, Mark Isaacson wrote: Hi everyone - I'm a D newbie with a very strong C++ background looking to get started. I've read The D Programming Language a couple of times now, but I've heard rumblings at several points in time from several people that some if its contents are now out of date or no longer reflect best practices. What would be the best way to bridge the learning gap between TDPL's publication and now? What other resources would be most useful in establishing a working knowledge of idiomatic D? What's the best way to stay informed about such changes in the future? (Is there a mailing list, or should I just be reading dmd changelogs?) Thanks in advance! I can just speak for myself, but I've been learning D by following the newsgroups and reading the phobos and druntime code. Not sure if there are quicker ways to get up to date.
Re: What learning resources are available?
On Tue, Feb 18, 2014 at 07:17:53PM +, Mark Isaacson wrote: Hi everyone - I'm a D newbie with a very strong C++ background looking to get started. I've read The D Programming Language a couple of times now, but I've heard rumblings at several points in time from several people that some if its contents are now out of date or no longer reflect best practices. I would say that most of TDPL is still applicable today. The parts that are out-of-date are mostly confined to the more advanced features. There has been some new syntax added since, but they have mostly been syntactic sugar, not fundamental changes, so you should notice very few discrepancies there. Another great resource is Ali Cehreli's introductory book to D: http://ddili.org/ders/d.en/ It takes a different approach from TDPL, and is more recent, so you may find it helpful. What would be the best way to bridge the learning gap between TDPL's publication and now? Honestly, there's not that much of a gap. I'd wager at least 80% (if not more) of TDPL is still relevant today. What other resources would be most useful in establishing a working knowledge of idiomatic D? Read Phobos source code, perhaps? :) I'm quite serious, actually. Phobos source code is actually very readable as far as standard libraries go (compared to, say, glibc, which is not only an eyesore but will give you a headache for weeks). I've found it a pleasure to read, for the most part. (There are some dark corners in Phobos code, but you don't have to go there to pick up the latest D practices!) What's the best way to stay informed about such changes in the future? (Is there a mailing list, or should I just be reading dmd changelogs?) [...] This forum should keep you pretty up-to-date. ;-) T -- One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie. -- The Silicon Valley Tarot
Re: Question about CPU caches and D context pointers
On 2014-02-18 1:13 PM, Casper Færgemand shortt...@hotmail.com wrote: On Tuesday, 18 February 2014 at 08:11:04 UTC, Dicebot wrote: I tested some prime sieves both in C++ and D. They worked fastest with dynamic arrays with a size matching the L1 cache. I presume the instructions are located elsewhere in the CPU. Does that mean ubyte[] = new ubyte[4092] is more likely to end up in the CPU cache than ubyte[4092] or the inverse ?
Re: Question about CPU caches and D context pointers
On Tuesday, 18 February 2014 at 19:55:20 UTC, Etienne wrote: On 2014-02-18 1:13 PM, Casper Færgemand shortt...@hotmail.com wrote: On Tuesday, 18 February 2014 at 08:11:04 UTC, Dicebot wrote: I tested some prime sieves both in C++ and D. They worked fastest with dynamic arrays with a size matching the L1 cache. I presume the instructions are located elsewhere in the CPU. Does that mean ubyte[] = new ubyte[4092] is more likely to end up in the CPU cache than ubyte[4092] or the inverse ? It is irrelevant. If data is used continiously it will end up in cache anyway (assuming it fits), location does not matter. What is important is if it is already prefetched upon first access, which is more likely for static arrays as they reside in the same memory page as their aggregator. Then it will save you from cache miss upon changing the buffer context frequently. But if you use the same buffer all the time during continious code flow it shouldn't impact where exactly it is located as it simply won't be removed from cache by newer data.
Re: What learning resources are available?
On Tuesday, 18 February 2014 at 19:17:55 UTC, Mark Isaacson wrote: Hi everyone - I'm a D newbie with a very strong C++ background looking to get started. I've read The D Programming Language a couple of times now, but I've heard rumblings at several points in time from several people that some if its contents are now out of date or no longer reflect best practices. What would be the best way to bridge the learning gap between TDPL's publication and now? What other resources would be most useful in establishing a working knowledge of idiomatic D? What's the best way to stay informed about such changes in the future? (Is there a mailing list, or should I just be reading dmd changelogs?) Thanks in advance! Combining other posts with my opinion of each item: A combination of: TDPL: overview of the language with justifications, should be very well targeted for an experienced C++ programmer http://ddili.org/ders/d.en/ for a few more up to date details and good basic introductions to anything you get confused by. Phobos code: Judicious use of the power of D. Not all good, but if you look at the more frequently updated modules you should get a nice picture. http://rosettacode.org/wiki/Category:D for lots of D solutions to common problems etc. Mostly by bearophile (I think?), stretching the limits of terse range-based D code.
Re: trace GC work
On 02/18/2014 10:10 AM, Ruslan Mullakhmetov wrote:
Hi,
Is it possible to trace GC allocation calls to determine times of
program death and have some stats?
So i want the following information:
- garbage collection starts at {time}
- garbage collection stops at {time}
- (optionally) gc took {time}, collected {size} bytes
thanks.
I may be totally off but I vaguely remember that it is possible to plug
in one's own garbage collector. It should be possible to write a garbage
collector that collects some statistics before calling back the default
GC functions.
Ali
Re: What learning resources are available?
On Tuesday, 18 February 2014 at 19:17:55 UTC, Mark Isaacson wrote: Hi everyone - I'm a D newbie with a very strong C++ background looking to get started. I've read The D Programming Language a couple of times now, but I've heard rumblings at several points in time from several people that some if its contents are now out of date or no longer reflect best practices. What would be the best way to bridge the learning gap between TDPL's publication and now? What other resources would be most useful in establishing a working knowledge of idiomatic D? What's the best way to stay informed about such changes in the future? (Is there a mailing list, or should I just be reading dmd changelogs?) Thanks in advance! This one is quite cool: https://github.com/PhilippeSigaud/D-templates-tutorial
Cannot get frame pointer to sort
--
struct Set(alias less = a b, T)
{
import std.algorithm;
import std.functional;
alias lessFun = binaryFun!(less);
int[] someContents;
this(R)(R r)
{
sort!(lessFun)(someContents);
}
}
unittest {
auto as2 = Set!((x,y) = x y , int)([2, 1, 3]);
}
-- http://dpaste.dzfl.pl/af6cb1a8d8ab
It works, if I provide a normal function or a string lambda as
'less'. However the code above results in the following error:
/d923/f233.d(11): Error: constructor
f233.__unittestL15_3.Set!((x, y) = x y,
int).Set.__ctor!(int[]).this cannot get frame pointer to sort
What's wrong?
Re: trace GC work
On Tuesday, 18 February 2014 at 18:10:40 UTC, Ruslan Mullakhmetov
wrote:
Hi,
Is it possible to trace GC allocation calls to determine times
of program death and have some stats?
So i want the following information:
- garbage collection starts at {time}
- garbage collection stops at {time}
- (optionally) gc took {time}, collected {size} bytes
thanks.
I believe you'll have to modify the runtime to achieve this. See
the gc folder[1]. An example of a custom garbage collector is
in the gcstub folder[2].
Mike
[1]
https://github.com/D-Programming-Language/druntime/tree/e47a00bff935c3f079bb567a6ec97663ba384487/src/gc
[2]
https://github.com/D-Programming-Language/druntime/blob/e47a00bff935c3f079bb567a6ec97663ba384487/src/gcstub/gc.d
Re: Cannot get frame pointer to sort
On Tuesday, 18 February 2014 at 22:28:08 UTC, Tobias Pankrath wrote: What's wrong? This looks like a bug to me, seeing as string predicate works. Although I don't get how you supply default template parameter for Set before explicit one :)
Re: Optimize my code =)
Hiho, I am happy to see that I could encourage so many people to discuss about this topic to not only give me interesting answer to my questions but also to analyse and evaluate features and performance of D. I have fixed the allocation performance problem via a custom destructor method which manually notifies the GC that its data is garbage so that the GC can free it in the next cycle and no longer have to determine if it is no longer used. This extremely speeded up the allocation tests but increased overall runtime performance by a very slight amount of time because memory is now freed contigeously. @Nick Sabalausky: Why should I remove .dub from the copy constructor? In my opinion this is important to keep both matrices (source and copy) independent from each other. The suggested COW feature for matrices sound interesting but also weird. I have to read more about that. Move semantics in D a needed and existing, however, I think that the D compiler isn't as good as the C++ compiler in determining what is moveable and what not. Another thing which is hopefully a bug in the current language implementation of D is the strange behaviour of the transpose method with the only line of code: return Matrix(this).transposeAssign(); In C++ for example this compiles without any problems and results in correct transposed matrix copies - this works due to the existance of move semantics in C++ and is one of the coolest features since C++11 which increased and simplified codes in many cases enormously for value types just as structs in D. I have ran several tests in order to test when the move assign or the move constructors are called in D and whenever I expected them to be called the copy-constructor or the postblit was called instead which was frustating imo. Perhaps I still haven't quite understood the things behind the scenes in D but it can't be the solution to always copy the whole data whenever I could instead have a move of the whole data on the heap. Besides that on suggestion which came up was that I could insert the Dimension module into the Matrix module as their are semantically working together. However, I find it better to have many smaller code snippets instead of fewer bigger ones and that's why I keep them both separated. I also gave scoped imports a try and hoped that they were able to reduce my executable file and perhaps increase the performance of my program, none of which was true - confused. Instead I now have more lines of code and do not see instantly what dependencies the module as itself has. So what is the point in scoped imports? The mixin keyword is also nice to have but it feels similar to a dirty C-macro to me where text replacement with lower abstraction (unlike templates) takes place. Of course I am wrong and you will teach me why but atm I have strange feelings about implementing codes with mixins. In this special case: perhaps it isn't a wise decision to merge addition with subtraction and perhaps I can find faster ways to do that which invole more differences in both actions which requires to split both methods up again. (theoretical, but it could be) Another weird thing is that the result ~= text(tabStr, this[r, c]) in the toString method is much slower than the two following lines of code: result ~= tabStr; result ~= to!string(this[r, c]); Does anybody have an answer to this? I am now thinking that I know the most important things about how to write ordinary (not super) efficient D code - laugh at me if you want :D - and will continue extending this benchmarking library and whenever I feel bad about a certain algorithm's performance I will knock here in this thread again, you know. :P In the end of my post I just want to summarize the benchmark history for the matrix multiplication as I think that it is funny: (All tests for two 1000x1000 matrices!) - The bloody first implementation of the matrix implementation (which worked) required about 39 seconds to finish. - Then I have finally found out the optimizing commands for the DMD and the multiplication performance double roughly to about 14 seconds. - I created an account here and due to your massive help the matrix multiplication required only about 5 seconds shortly after due to better const, pure and nothrow usage. - Through the shift from class to struct and some optimizations in memory layout and further usage improvements of const, pure and nothrow as well as several array feature usages and foreach loop the algorithm performance raised once again and required about 3,7 seconds. - The last notifiable optimization was the implemenatation based on pointer arithmentics which again improved the performance from 3,7 seconds to roughly about 2 seconds. Due to this development I see that there is still a possibility that we could beat the 1,5 seconds from Java or even the 1,3 seconds from C++! (based on my machine: 64bit-archlinux,
UDA initialize a user defined type attribute field
When a user defined type is used as an attribute like this:
// the attribute
struct MyAttrib
{
immutable string name;
imuttable int sz;
immutable string defaultvalue;
}
// using the attribute
class Data
{
// field 'id' has attribute MyAttrib with name and sz set to
'fancy name'
// and 10 resp.
@MyAttrib( fancy name, 10 )
long id;
...
}
But how do I only set the MyAttrib.defaultvalue?
class OtherData
{
//@MyAttrib( ??defaultvalue = null ?? )
//@MyAttrib( string.init, int.init, null ) //seems to work?
long id;
...
}
MyAttrib instances may be initialized like this:
auto myattrib = { defaultvalue:null };
But this seems not possible when using MyAttrib as attribute.
Re: UDA initialize a user defined type attribute field
On Tuesday, 18 February 2014 at 23:43:56 UTC, Arjan wrote: But how do I only set the MyAttrib.defaultvalue? You could do it by adding a constructor to MyAttrib that only takes one string and fills it in that way.
Re: Optimize my code =)
Robin: the existance of move semantics in C++ and is one of the coolest features since C++11 which increased and simplified codes in many cases enormously for value types just as structs in D. I guess Andrei doesn't agree with you (and move semantics in C++11 is quite hard to understand). I also gave scoped imports a try and hoped that they were able to reduce my executable file and perhaps increase the performance of my program, none of which was true - confused. Instead I now have more lines of code and do not see instantly what dependencies the module as itself has. So what is the point in scoped imports? Scoped imports in general can't increase performance. Their main point is to avoid importing modules that are needed only by templated code. So if you don't instantiate the template, the liker works less and the binary is usually smaller (no moduleinfo, etc). Another weird thing is that the result ~= text(tabStr, this[r, c]) in the toString method is much slower than the two following lines of code: result ~= tabStr; result ~= to!string(this[r, c]); Does anybody have an answer to this? It doesn't look too much weird. In the first case you are allocating and creating larger strings. But I don't think matrix printing is a bottleneck in a program. - Then I have finally found out the optimizing commands for the DMD This is a small but common problem. Perhaps worth fixing. There are still many ways to further improve the performance. For examply by using LDC Latest stable and unstable versions of LDC2, try it: https://github.com/ldc-developers/ldc/releases/tag/v0.12.1 https://github.com/ldc-developers/ldc/releases/tag/v0.13.0-alpha1 on certain hardwares, paralellism and perhaps by implementing COW with no GC dependencies. And of course I may miss many other possible optimization features of D. Matrix multiplication can be improved a lot tiling the matrix (or better using a cache oblivious algorithm), using SSE/AVX2, using multiple cores, etc. As starting point you can try to use std.parallelism. It could speed up your code on 4 cores with a very limited amount of added code. Bye, bearophile
Re: UDA initialize a user defined type attribute field
On Tuesday, 18 February 2014 at 23:46:28 UTC, Adam D. Ruppe wrote:
On Tuesday, 18 February 2014 at 23:43:56 UTC, Arjan wrote:
But how do I only set the MyAttrib.defaultvalue?
You could do it by adding a constructor to MyAttrib that only
takes one string and fills it in that way.
But what happens than when only the first field 'name' is used in
MyAttrib like this:
class OtherData
{
@MyAttrib( fancy name )
long id;
...
}
I guess the field MyAttrib.defaultvalue will be assigned the
value fancy name?
Re: UDA initialize a user defined type attribute field
Arjan:
MyAttrib instances may be initialized like this:
auto myattrib = { defaultvalue:null };
But this seems not possible when using MyAttrib as attribute.
This could become a D enhancement request.
I guess the field MyAttrib.defaultvalue will be assigned the
value fancy name?
Unfortunately D doesn't have named arguments.
You can use chains, returning this from some methods:
MyAttrib().setName(Foo).setSz(10).setDefaultValue(Bar)
Bye,
bearophile
Re: UDA initialize a user defined type attribute field
On 02/18/2014 03:43 PM, Arjan wrote:
When a user defined type is used as an attribute like this:
// the attribute
struct MyAttrib
{
immutable string name;
imuttable int sz;
immutable string defaultvalue;
}
// using the attribute
class Data
{
// field 'id' has attribute MyAttrib with name and sz set to 'fancy
name'
// and 10 resp.
@MyAttrib( fancy name, 10 )
long id;
...
}
But how do I only set the MyAttrib.defaultvalue?
class OtherData
{
//@MyAttrib( ??defaultvalue = null ?? )
//@MyAttrib( string.init, int.init, null ) //seems to work?
long id;
...
}
MyAttrib instances may be initialized like this:
auto myattrib = { defaultvalue:null };
But this seems not possible when using MyAttrib as attribute.
This problem has nothing to do with UDAs and can be solved similar to
regular cases, e.g. by using a factory function:
// the attribute
struct MyAttrib
{
immutable string name;
immutable int sz;
immutable string defaultvalue;
}
MyAttrib makeMyAttribWithDefaultValue(string defaultValue)
{
return MyAttrib(MyAttrib.name.init, MyAttrib.sz.init, defaultValue);
}
// using the attribute
class Data
{
// field 'id' has attribute MyAttrib with name and sz set to 'fancy
name'
// and 10 resp.
@MyAttrib( fancy name, 10 )
long id;
@makeMyAttribWithDefaultValue(hello)
int i;
}
void main()
{
pragma(msg, __traits(getAttributes, Data.id));
pragma(msg, __traits(getAttributes, Data.i));
}
Ali
Re: Optimize my code =)
On Tuesday, 18 February 2014 at 23:36:12 UTC, Robin wrote:
Another thing which is hopefully a bug in the current language
implementation of D is the strange behaviour of the transpose
method with the only line of code:
return Matrix(this).transposeAssign();
Matrix(this) not compiling when 'this' is const is a bug. That's
why I had to replace it with assignment. Postblit still has some
unresolved problems.
However, you should note that you have a bigger bug in that
transposeAssign() returns a reference :) So unless transpose()
returns Matrix (instead of ref Matrix), that's a problem.
In C++ for example this compiles without any problems and
results in correct transposed matrix copies - this works due to
the existance of move semantics in C++ and is one of the
coolest features since C++11 which increased and simplified
codes in many cases enormously for value types just as structs
in D.
The fact that it compiles in C++ is a problem (this illustrates
your initial implementation of transpose() translated into C++):
struct Matrix
{
// ref Matrix transpose() const;
S transpose() const { return
Matrix(*this).transposeAssign(); }
// ref Matrix transposeAssign();
S transposeAssign() { return *this; }
};
int main(int argc, char** argv)
{
Matrix m1;
Matrix m2 = m1.transpose(); // ooops!
}
I have ran several tests in order to test when the move assign
or the move constructors are called in D and whenever I
expected them to be called the copy-constructor or the postblit
was called instead which was frustating imo.
I've posted a complete illustration on how D moves rvalues,
browse this thread back a bit.
I also gave scoped imports a try and hoped that they were able
to reduce my executable file and perhaps increase the
performance of my program, none of which was true - confused.
Instead I now have more lines of code and do not see instantly
what dependencies the module as itself has. So what is the
point in scoped imports?
They don't pollute outer scope with symbols. If you just need to
call a couple of functions from std.random inside *one* function,
there's no need to pull names from std.random into the whole
module.
The mixin keyword is also nice to have but it feels similar to
a dirty C-macro to me where text replacement with lower
abstraction (unlike templates) takes place. Of course I am wrong
Yes you are :) It's not dirty and it's certainly not a macro.
It's a great feature for generating code at compile time. For
examples just browse through Phobos (e.g. std.functional), or
take a look at the code in this thread:
http://forum.dlang.org/thread/mailman.158.1391156715.13884.digitalmar...@puremagic.com
Maybe it's your syntax highlighting that throws you off? Then use
q{} insead of :)
Another weird thing is that the result ~= text(tabStr, this[r,
c]) in the toString method is much slower than the two
following lines of code:
result ~= tabStr;
result ~= to!string(this[r, c]);
Does anybody have an answer to this?
Probably due to extra allocation in text(tabStr, this[r,c]) since
it will perform ~ under the hood, while appender already has
storage.
