Re: Looking for writing parallel foreach kind of statement for nested for-loops
On 2013-02-10 02:22, Sparsh Mittal wrote:
The current reply answers my question, but I was just curious. Can we have a
method which divides the 2d region as follows: 8*12 divided into 4*6 to each of
4 threads.
Think again if you need that. Things start getting pretty ugly. :)
const uint parts = 2; // in each dimension
foreach (block; parallel(iota(parts*parts))) {
uint p1 = block / parts;
foreach (i; (p1*N/parts)..(p1==parts-1 ? N : (p1+1)*N/parts)) {
uint p2 = block % parts;
foreach (j; (p2*M/parts)..(p2==parts-1 ? M : (p2+1)*M/parts)) {
func(i, j, p1, p2, block);
}
}
}
Re: Creating an array of default-constructed class instances
On Sunday, 10 February 2013 at 06:57:42 UTC, Ali Çehreli wrote: On 02/09/2013 10:52 PM, Ali Çehreli wrote: > auto things = iota(10).map!(i => new Thing(i))().array; Actually, without the extra parentheses: auto things = iota(10).map!(i => new Thing(i)).array; Ali It's a shame there isn't any simple syntax for it, but that's some neat and flexible code. Thanks!
Re: Creating an array of default-constructed class instances
On 02/09/2013 10:52 PM, Ali Çehreli wrote: > auto things = iota(10).map!(i => new Thing(i))().array; Actually, without the extra parentheses: auto things = iota(10).map!(i => new Thing(i)).array; Ali
Re: Creating an array of default-constructed class instances
On 02/09/2013 10:14 PM, Simon wrote:
> Hi, I'm new to the D programming language. Overall I'm liking
> things very much, but I'm still getting the hang of a few things.
>
> Here's a basic programming pattern: I have a class called Thing,
> and while I'm coding I decide I need N Thing instances.
>
> In C++ that's a matter of
>
> std::vector things(N);
>
> In python, I can use a list comprehension.
>
> things = [Thing() for _ in range(N)]
>
> However, the obvious D version doesn't work.
>
> auto things = new Thing[N];
>
> Because Thing.init is null, this produces an array of null
> references. Of course, I can write a for loop to fill in the
> array after creation, but this feels very un-D-like. Is there a
> straightforward way to create a bunch of class instances?
Here is one way:
import std.stdio;
import std.range;
import std.algorithm;
class Thing
{
int i;
this(int i)
{
this.i = i;
}
}
void main()
{
auto things = iota(10).map!(i => new Thing(i))().array;
}
Ali
--
D Programming Language Tutorial: http://ddili.org/ders/d.en/index.html
Re: Creating an array of default-constructed class instances
On Sunday, 10 February 2013 at 06:14:37 UTC, Simon wrote: Hi, I'm new to the D programming language. Overall I'm liking things very much, but I'm still getting the hang of a few things. Here's a basic programming pattern: I have a class called Thing, and while I'm coding I decide I need N Thing instances. In C++ that's a matter of std::vector things(N); In python, I can use a list comprehension. things = [Thing() for _ in range(N)] However, the obvious D version doesn't work. auto things = new Thing[N]; Because Thing.init is null, this produces an array of null references. Of course, I can write a for loop to fill in the array after creation, but this feels very un-D-like. Is there a straightforward way to create a bunch of class instances? You can create separate function which fills array with instances and return it. You can make Thing a struct aliased to array of classes which again initializes properly in constructor an array. But then you should take care that struct constructor is called.
Creating an array of default-constructed class instances
Hi, I'm new to the D programming language. Overall I'm liking things very much, but I'm still getting the hang of a few things. Here's a basic programming pattern: I have a class called Thing, and while I'm coding I decide I need N Thing instances. In C++ that's a matter of std::vector things(N); In python, I can use a list comprehension. things = [Thing() for _ in range(N)] However, the obvious D version doesn't work. auto things = new Thing[N]; Because Thing.init is null, this produces an array of null references. Of course, I can write a for loop to fill in the array after creation, but this feels very un-D-like. Is there a straightforward way to create a bunch of class instances?
Re: Error: not a property - ?
On Sunday, 10 February 2013 at 03:45:37 UTC, Jonathan M Davis wrote: On Sunday, February 10, 2013 04:38:56 Era Scarecrow wrote: Where should I add to the bug tracker so the error message can be improved? Just create a new bug report for it: http://d.puremagic.com/issues - Jonathan M Davis Found it's bug 5010; Added comment for that specific case. http://d.puremagic.com/issues/show_bug.cgi?id=5010
Re: Error: not a property - ?
On Sunday, February 10, 2013 04:38:56 Era Scarecrow wrote: > Where should I add to the bug tracker so the error message can > be improved? Just create a new bug report for it: http://d.puremagic.com/issues - Jonathan M Davis
Re: Error: not a property - ?
On Sunday, 10 February 2013 at 03:24:37 UTC, Jonathan M Davis
wrote:
On Sunday, February 10, 2013 04:16:26 Era Scarecrow wrote:
This is an unexpected error; Seems it's the result of not
down-casting a variable-type. Is this a bug? Or just need a
better error message?
Version: DMD32 D Compiler v2.061
struct S {
void test(uint v) @property {}
void test2(ulong v) @property {}
}
ulong x;
S s;
s.test2 = x;
s.test = x; //s.test is not a property
It's not a bug. The assignment is illegal, because a you can't
assign a ulong to a uint without casting, but the error message
obviously isn't very good. It probably gives that error
whenever you try and use the property syntax, and there's no
variable or function with that name that compiles with the
given argument. It really should be indicating that the
argument itself is invalid, but however the combination of
lowering and error messages works, you end up with a less than
helpful error message.
I figured as much. Very difficult to figure out the culprit when
it's from bitfields mixed with perfectly normal code for
assignment.
Where should I add to the bug tracker so the error message can
be improved?
Re: Error: not a property - ?
On Sunday, February 10, 2013 04:16:26 Era Scarecrow wrote:
> This is an unexpected error; Seems it's the result of not
> down-casting a variable-type. Is this a bug? Or just need a
> better error message?
>
> Version: DMD32 D Compiler v2.061
>
>
>struct S {
> void test(uint v) @property {}
> void test2(ulong v) @property {}
>}
>
>ulong x;
>S s;
>
>s.test2 = x;
>s.test = x; //s.test is not a property
It's not a bug. The assignment is illegal, because a you can't assign a ulong
to a uint without casting, but the error message obviously isn't very good. It
probably gives that error whenever you try and use the property syntax, and
there's no variable or function with that name that compiles with the given
argument. It really should be indicating that the argument itself is invalid,
but however the combination of lowering and error messages works, you end up
with a less than helpful error message.
- Jonathan M Davis
Error: not a property - ?
This is an unexpected error; Seems it's the result of not
down-casting a variable-type. Is this a bug? Or just need a
better error message?
Version: DMD32 D Compiler v2.061
struct S {
void test(uint v) @property {}
void test2(ulong v) @property {}
}
ulong x;
S s;
s.test2 = x;
s.test = x; //s.test is not a property
Re: Line gaps with text files
This works better:
import std.stdio;
import std.file;
void main() {
//string s = readText("s.txt");
string s;
foreach(line; File("s.txt", "r").byLine()) {
s ~= line~"\r\n";
}
s = s[0..$-2];
writeln([s]);
File("s.txt", "w").write(s);
}
But one text file program says it has solitary carriage returns
in it.
Re: For DLLs, what does export actually do?
On 09/02/2013 20:39, Benjamin Thaut wrote:
Am 09.02.2013 21:35, schrieb Ben Davis:
Hi,
I'm working on a multimedia driver DLL, i.e. one that Windows loads on
behalf of any program that uses the Windows multimedia API.
I'm using a .def file with an EXPORTS section, and I've also got all the
relevant functions marked as 'export' in the code.
What I'm finding is, if I remove the 'export' attribute but keep the
EXPORTS section, it all still works; but if I keep the 'export'
attribute and remove the EXPORTS section, then it doesn't work.
Just wondering why this is, and whether the 'export' attribute is
actually programmed to do anything at the moment :)
Thanks,
Ben :)
Yes it is, but its only working properly for global functions. It works
partially for classes and not at all for all remaining cases. The export
attribute is currently only usefull if you want to do a C-Style
interface for your Dll.
My functions are "export extern (Windows)" - I think they're global...?
For example:
export extern(Windows) LRESULT DriverProc(DWORD_PTR dwDriverId, HDRVR
hdrvr, UINT msg, LONG lParam1, LONG lParam2) nothrow { ... }
Re: For DLLs, what does export actually do?
On 09/02/2013 20:44, Andrej Mitrovic wrote: On 2/9/13, Ben Davis wrote: Hi, I'm working on a multimedia driver DLL, i.e. one that Windows loads on behalf of any program that uses the Windows multimedia API. I'm using a .def file with an EXPORTS section, and I've also got all the relevant functions marked as 'export' in the code. Export in code allows you to avoid listing exported functions in the DEF file. However you should likely still use the DEF file even if it lacks a list, as I recall there's a bug related to not using DEF files (I can't find the issue right now). (Oops, silly Thunderbird) I know which issue you mean, because I came across it earlier. It's something about needing "EXETYPE NT" and "SUBSYSTEM WINDOWS" or else something bad happens with thread-local storage. I don't think it had anything to do with exports. What you're telling me (about the purpose of export in code) is what I assumed was the intention, but the fact is it's not behaving that way. If I mark the functions as export in the code, but remove the EXPORTS section from the .def file (but keep the rest of the .def file), then the DLL doesn't work, which suggests that the export table did not contain those functions. Perhaps the exports in the code only apply if the .def is entirely missing? Is that the desired behaviour? (I won't be trying that, as I know it would break in other ways then.) Ben :)
Re: std.process.system and friends
I'm trying to write a script in D for building D projects. They are dbuilder who do this . you can fork it https://github.com/dbuilder-developers/dbuilder
Line gaps with text files
I'm using Windows and get gaps (blank lines) when using readText
and std.stdio.write.
import std.stdio;
import std.file;
void main() {
string s = readText("s.txt");
writeln('[', s, ']');
File("s.txt", "w").write(s);
}
notepad.exe opens alright, (if you don't save as File(.., "wb")).
But I'm having trouble with some others like GtkD. Also writeln
always does it right.
Re: Looking for writing parallel foreach kind of statement for nested for-loops
for(int i=1; i< N; i++)<==>foreach(i; iota(1, N))
so you can use: foreach(i; parallel(iota(1, N))) { ... }
Thanks a lot. This one divides the x-cross-y region by rows.
Suppose dimension is 8*12 and 4 parallel threads are there, so
current method is dividing by 2*12 to each of 4 threads.
The current reply answers my question, but I was just curious.
Can we have a method which divides the 2d region as follows: 8*12
divided into 4*6 to each of 4 threads.
Re: A little of coordination for Rosettacode
SomeDude: ... Partial translation of rcrpg-Python: http://codepad.org/SflrKqbT Partial translation of permutations_rank_of_a_permutation-Python: http://codepad.org/El9SQwOE Plus a better Perl implementation of the uniform() on BigInts: http://codepad.org/LGcMpk2f Partial translation of the universal_turing_machine-Ruby: http://codepad.org/nUXLzAg2 Bye, bearophile codepad.org doesn't work at all here. Maybe you should use dpaste (or pastebin for other languages) instead ? Links in the same order: http://dpaste.dzfl.pl/10eff346 http://dpaste.dzfl.pl/bfde8010 http://dpaste.dzfl.pl/3a172308 http://dpaste.dzfl.pl/22b7a931 Bye, bearophile
Re: A little of coordination for Rosettacode
On 9-2-2013 23:14, SomeDude wrote: codepad.org doesn't work at all here. Maybe you should use dpaste (or pastebin for other languages) instead ? It's not working for me either. It's probably a temporary problem. It worked fine before.
Re: search of a workaround
This works so far: auto funcAttr = functionAttributes!(fun); if (FunctionAttribute.pure_ & funcAttr) s ~= " pure"; if (FunctionAttribute.nothrow_ & funcAttr) s ~= " nothrow"; if (FunctionAttribute.ref_ & funcAttr) s ~= " ref"; if (!isMutable!(typeof(fun))) s ~= " const"; But it's curious that FunctionAttributes has no const, immutable, inout or shared...
Re: Looking for writing parallel foreach kind of statement for nested for-loops
On 2013-02-09 23:32, Sparsh Mittal wrote:
I saw foreach and parallel commands on
http://dlang.org/phobos/std_parallelism.html
I have nested for-loops as follows:
for(int i=1; i< N; i++)
{
for(int j=1; j < M; j++)
{
func(i,j);
}
}
Here func(i,j) is such that there is no dependency or communication b/w
different (i,j) tuple values. Thus, problem is very simple.
Huh?
for(int i=1; i< N; i++)<==>foreach(i; iota(1, N))
so you can use: foreach(i; parallel(iota(1, N))) { ... }
Re: search of a workaround
On Saturday, 9 February 2013 at 22:23:07 UTC, Namespace wrote:
It seems your template has problems with this:
struct A { }
class B {
public:
const int bar(ref A a) {
return 42;
}
mixin(rvalue!(bar));
}
remove the 'const' and it works fine.
It seems that D has no functionality, to detect if a method is
const.
Re: search of a workaround
It seems your template has problems with this:
struct A { }
class B {
public:
const int bar(ref A a) {
return 42;
}
mixin(rvalue!(bar));
}
remove the 'const' and it works fine.
Re: A little of coordination for Rosettacode
On Tuesday, 5 February 2013 at 20:10:37 UTC, bearophile wrote: Jos van Uden: I'll give it a shot if you like. The RCRPG I'd like to try first. I have already partially written those: Partial translation of rcrpg-Python: http://codepad.org/SflrKqbT Partial translation of permutations_rank_of_a_permutation-Python: http://codepad.org/El9SQwOE Plus a better Perl implementation of the uniform() on BigInts: http://codepad.org/LGcMpk2f Partial translation of the universal_turing_machine-Ruby: http://codepad.org/nUXLzAg2 Bye, bearophile codepad.org doesn't work at all here. Maybe you should use dpaste (or pastebin for other languages) instead ?
Re: eating whitespace
Am 09.02.2013, 22:30 Uhr, schrieb Andrej Mitrovic
:
"f\too\t\n\rb\nar".removechars("\t\n\r")
thanks, works...
Peter
Re: eating whitespace
On 2/9/13, Peter Sommerfeld wrote:
> I wonder what the best, that means the fastest way is
> to remove all whitespace " \t\n\r" from as string.
> Whitespace are distributed erratically within the string.
>
> Peter
>
Try "f\too\t\n\rb\nar".removechars("\t\n\r")
eating whitespace
I wonder what the best, that means the fastest way is to remove all whitespace " \t\n\r" from as string. Whitespace are distributed erratically within the string. Peter
Re: For DLLs, what does export actually do?
On 2/9/13, Ben Davis wrote: > Hi, > > I'm working on a multimedia driver DLL, i.e. one that Windows loads on > behalf of any program that uses the Windows multimedia API. > > I'm using a .def file with an EXPORTS section, and I've also got all the > relevant functions marked as 'export' in the code. Export in code allows you to avoid listing exported functions in the DEF file. However you should likely still use the DEF file even if it lacks a list, as I recall there's a bug related to not using DEF files (I can't find the issue right now).
Re: For DLLs, what does export actually do?
Am 09.02.2013 21:35, schrieb Ben Davis: Hi, I'm working on a multimedia driver DLL, i.e. one that Windows loads on behalf of any program that uses the Windows multimedia API. I'm using a .def file with an EXPORTS section, and I've also got all the relevant functions marked as 'export' in the code. What I'm finding is, if I remove the 'export' attribute but keep the EXPORTS section, it all still works; but if I keep the 'export' attribute and remove the EXPORTS section, then it doesn't work. Just wondering why this is, and whether the 'export' attribute is actually programmed to do anything at the moment :) Thanks, Ben :) Yes it is, but its only working properly for global functions. It works partially for classes and not at all for all remaining cases. The export attribute is currently only usefull if you want to do a C-Style interface for your Dll. Kind Regards Benjamin Thaut
For DLLs, what does export actually do?
Hi, I'm working on a multimedia driver DLL, i.e. one that Windows loads on behalf of any program that uses the Windows multimedia API. I'm using a .def file with an EXPORTS section, and I've also got all the relevant functions marked as 'export' in the code. What I'm finding is, if I remove the 'export' attribute but keep the EXPORTS section, it all still works; but if I keep the 'export' attribute and remove the EXPORTS section, then it doesn't work. Just wondering why this is, and whether the 'export' attribute is actually programmed to do anything at the moment :) Thanks, Ben :)
windows 64bit variadic functions
I have this small test program, it will crash when compiled on x64
windows, but it works fine on 32bit windows. What am I doing wrong?
import core.vararg;
import std.stdio;
void print(string fmt, ...)
{
auto arg = va_arg!(const(char)[])(_argptr);
writefln(fmt ~ arg);
}
void main(string[] args)
{
print("+++","---");
}
Kind Regards
Benjamin Thaut
Re: best idiom for insert if not present; else use value in assoc array
On Saturday, 9 February 2013 at 00:54:58 UTC, Andrej Mitrovic wrote: Feel free to file an enhancement request. http://d.puremagic.com/issues/show_bug.cgi?id=9491 Hopefully that is clear.
Re: How to read fastly files ( I/O operation)
some idea such as letter counting: rename identifier trimming sequence from quality value to cutoff convert to a binary format more idea later
Re: search of a workaround
(I'll ask to remove one limitation):
http://d.puremagic.com/issues/show_bug.cgi?id=9489
typeof(scoped!Foo(1))[10] foos; // Not initialized.
foreach (i, ref f; foos)
// f = new Foo(i * 10);
// f = scoped!Foo(i * 10);
f.x = i * 10;
What's the right/good way to initialize a scoped class instance?
Currently this doesn't work:
import std.typecons;
class Foo {
int x;
this(int x_) { initialize(x_); }
void initialize(int x_) {
this.x = x_;
}
}
void main() {
typeof(scoped!Foo(1))[10] foos;
foreach (i, ref f; foos)
f.initialize(i * 10);
}
Bye,
bearophile
Re: search of a workaround
monarch_dodra:
I mean structs you can pack together in an array, eg:
S[10] s10; //10 structs S
You can't do that with classes. Sure, you can put 10 class
*references* in an array, but the *instances* themselves need
to be individually allocated.
This kind of works, with some limitations (I'll ask to remove one
limitation):
import std.stdio, std.conv, std.typecons;
class Foo {
int x;
this(int x_) { this.x = x_; }
override string toString() { return text(x); }
}
void main() {
// scoped!Foo[10] foos;
typeof(scoped!Foo(1))[10] foos; // Not initialized.
foreach (i, ref f; foos)
// f = new Foo(i * 10);
// f = scoped!Foo(i * 10);
f.x = i * 10;
// writeln(foos);
foreach (ref f; foos)
writeln(f.x);
}
Bye,
bearophile
Re: search of a workaround
On Saturday, 9 February 2013 at 12:10:57 UTC, Namespace wrote: In particular, you can't pack classes in a table, for example. I don't understand. I mean structs you can pack together in an array, eg: S[10] s10; //10 structs S You can't do that with classes. Sure, you can put 10 class *references* in an array, but the *instances* themselves need to be individually allocated. This can be a problem if you want to represent an image, for example, and "S" is an RGB quad.
Re: search of a workaround
I'm not sure what "in spite of" is. No offense, but you seem to be the only person having problems with this. Maybe I'm the only one who uses so many structs. That happens when you have strong C++ background. I miss '&'. :D And the workarounds are plenty: My proposal, templatizing for auto ref, pass by value... I don't know. Templatizing just for auto ref seems a bad Idea for me. But pass by value for small structs shouldn't be much overhead. In particular, you can't pack classes in a table, for example. I don't understand. That said, if you pass everything by value, and make things < 16 bytes structs, and > 16 bytes classes, you should get a good deal. Yes, that sounds good.
Re: search of a workaround
On Saturday, 9 February 2013 at 10:05:21 UTC, Namespace wrote: I that directed at me? I'm not sure how it relates? Yes, that's a question for you. Why would you take in spite of everything still structs rather than classes? I'm not sure what "in spite of" is. No offense, but you seem to be the only person having problems with this. And the workarounds are plenty: My proposal, templatizing for auto ref, pass by value... As for classes, they're fine if the object in question is somewhat big, but it's not a solution for tiny struct, such as color info or whatnot. In particular, you can't pack classes in a table, for example. That said, if you pass everything by value, and make things < 16 bytes structs, and > 16 bytes classes, you should get a good deal.
Re: search of a workaround
I that directed at me? I'm not sure how it relates? Yes, that's a question for you. Why would you take in spite of everything still structs rather than classes?
Re: search of a workaround
On Friday, 8 February 2013 at 23:45:09 UTC, Namespace wrote: Thank you. But it looks ugly, and I dislike the use of such constructs for such simple feature. But cool thing. :D I like the meta stuff of D. :) Other favorites? One of the advantages of using this approach though is that it emulates auto ref. That means that if and when they get implemented for non-temlates, you'll need minimal code change to exploit it. Also, instead of using the mixin, (indeed, kind of ugly), you could just print out the "rvalue!foo" in a unittest block, and copy paste it. It's boilerplate code, but copy paste is at least a bit safer than hand writen. And more convenient. On Friday, 8 February 2013 at 23:49:01 UTC, Namespace wrote: BTW: What's stopping you from using a class instead of a struct? I that directed at me? I'm not sure how it relates?
