Re: Where can I find the DEFINITION of vibe IOMode ??
On Saturday, 5 September 2020 at 19:22:17 UTC, drug wrote: 05.09.2020 22:17, Andy Balba пишет: Where do I fine where IOMode is defined.. as in the last line of ... module vibe.core.stream; import vibe.internal.traits : checkInterfaceConformance, validateInterfaceConformance; import vibe.internal.interfaceproxy; import core.time; import std.algorithm; import std.conv; public import eventcore.driver : IOMode; After endless searches, I find many references to it, but never a DEFINITION of it https://github.com/vibe-d/eventcore/blob/a027c233c2542de8372bbff25d0a4804f32a094e/source/eventcore/driver.d#L1087 @drug: thank you..I'm now left with resolving @blocking
Where can I find the DEFINITION of vibe IOMode ??
Where do I fine where IOMode is defined.. as in the last line of ... module vibe.core.stream; import vibe.internal.traits : checkInterfaceConformance, validateInterfaceConformance; import vibe.internal.interfaceproxy; import core.time; import std.algorithm; import std.conv; public import eventcore.driver : IOMode; After endless searches, I find many references to it, but never a DEFINITION of it
Re: D binary io functions
On Sunday, 30 August 2020 at 10:02:09 UTC, Arjan wrote: On Sunday, 30 August 2020 at 06:00:20 UTC, Andy Balba wrote: going nuts trying to figure out which D functions will read/write binary files see this blog: http://nomad.uk.net/articles/working-with-files-in-the-d-programming-language.html Yes, Great, many thanks! This is the kind of online docs Dlang needs more of. Links for these "great docs" addressing various topics should be collected into a Dlang.org online file, where each "great doc" contains a link, followed by a brief description. Getting good and useful, online file-io docs for C++ takes a few minutes, but getting equivalent useful information on Dlang functions took me hours, with no successful outcome. IMHO Dlang.org online doc related to file io are too terse to be useful to anyone trying to learn Dlang, and are only useful to those that already familiar with them and who only need a "syntax reminder"
D binary io functions
going nuts trying to figure out which D functions will read/write binary files
Re: generating random numbers
On Monday, 10 August 2020 at 15:43:04 UTC, Andy Balba wrote:
On Monday, 10 August 2020 at 15:13:51 UTC, bachmeier wrote:
On Monday, 10 August 2020 at 14:20:23 UTC, bachmeier wrote:
On Monday, 10 August 2020 at 05:51:07 UTC, Andy Balba wrote:
generating random numbers using
https://dlang.org/library/std/random/uniform01.html
I find the example given in this section totally
incomprehensible
.. Can any help me answer two simple questions:
How to generate a random floating number in range [0,1) ?
How to set a seed value, prior to generating random values ?
Strange example for sure. I'd recommend checking out the
examples on the landing page for std.random:
https://dlang.org/library/std/random.html
I created a PR with a hopefully clearer example:
https://github.com/dlang/phobos/pull/7588
Ahhh yes, yes .. this is the way to write Dlang example code :
https://dlang.org/library/std/random.html
... a very neat random byte generator is at
https://github.com/LightBender/SecureD/tree/master/source/secured
here's the essential code :
import std.digest;
import std.stdio;
import std.exception;
@trusted ubyte[] random (uint bytes)
{
if (bytes == 0)
{ printf("number of bytes must be > zero"); return null; }
ubyte[] buffer = new ubyte[bytes];
try
{ File urandom = File("/dev/urandom", "rb");
urandom.setvbuf (null, _IONBF);
scope(exit) urandom.close();
try
{ buffer= urandom.rawRead(buffer); }
catch(ErrnoException ex)
{ printf("Cant get next random bytes"); return null;}
catch(Exception ex)
{ printf("Cant get next random bytes"); return null; }
}
catch(ErrnoException ex)
{ printf("Cant initialize system RNG"); return null; }
catch(Exception ex)
{ printf ("Cant initialize system RNG"); return null; }
return buffer;
}
void main()
{
ubyte[] rnd1 = random(32);
writeln("32Bytes: ", toHexString!(LetterCase.lower)(rnd1));
ubyte[] rnd2 = random(128);
writeln("128Bytes: ", toHexString!(LetterCase.lower)(rnd2));
ubyte[] rnd3 = random(512);
writeln("512Bytes:");
writeln(toHexString!(LetterCase.lower)(rnd3));
ubyte[] rnd4 = random(2048);
writeln("2048 Bytes:");
writeln(toHexString!(LetterCase.lower)(rnd4));
}
Re: generating random numbers
On Monday, 10 August 2020 at 15:13:51 UTC, bachmeier wrote: On Monday, 10 August 2020 at 14:20:23 UTC, bachmeier wrote: On Monday, 10 August 2020 at 05:51:07 UTC, Andy Balba wrote: generating random numbers using https://dlang.org/library/std/random/uniform01.html I find the example given in this section totally incomprehensible .. Can any help me answer two simple questions: How to generate a random floating number in range [0,1) ? How to set a seed value, prior to generating random values ? Strange example for sure. I'd recommend checking out the examples on the landing page for std.random: https://dlang.org/library/std/random.html I created a PR with a hopefully clearer example: https://github.com/dlang/phobos/pull/7588 Ahhh yes, yes .. this is the way to write Dlang example code : https://dlang.org/library/std/random.html
generating random numbers
generating random numbers using https://dlang.org/library/std/random/uniform01.html I find the example given in this section totally incomprehensible .. Can any help me answer two simple questions: How to generate a random floating number in range [0,1) ? How to set a seed value, prior to generating random values ?
How does one run a linux system command from a D main() fcn ?
i.e. D equivalent to C++ command system("MyExe")
Re: safety and auto vectorization
On Monday, 3 August 2020 at 19:42:51 UTC, Steven Schveighoffer wrote: On 8/3/20 3:22 PM, Bruce Carneal wrote: Thanks Steve (and Chad). Summary: underspecified, varying behavior across versions, buggy. Steve, what's the best way for me to report this? Are spec issues lumped in with the other bugzilla reports? Yep. You can file under dlang.org with the spec keyword. Although this looks like it's not exactly a spec issue. I'd start it as a dmd bug (I don't know the exact interaction with the compiler and the library). It might also be a druntime bug. -Steve FWIW ..using gdc Debian 8.3.0-6, dst[]= generates a range error auto a = [1, 2, 3]; auto b = [4, 5, 6]; int[] dst = new int[4]; // note the extra element dst[] = a[] + b[]; writeln(dst[3]);
Re: 2-D array initialization
On Sunday, 2 August 2020 at 06:37:06 UTC, tastyminerals wrote:
You haven't said anything about efficiency because if you care
and your arrays are rather big, you better go with
https://github.com/libmir/mir-algorithm as mentioned above. It
might be a little finicky at the start but this post:
https://tastyminerals.github.io/tasty-blog/dlang/2020/03/22/multidimensional_arrays_in_d.html should get you up to speed.
Keep in mind that std.array.staticArray is not efficient for
large arrays.
If you want to stick to standard D, I would not initialize a 2D
array because it is just cumbersome but rather use a 1D array
and transform it into 2D view on demand via ".chunks" method.
Here is an example.
import std.range;
import std.array;
void main() {
int[] arr = 20.iota.array;
auto arr2dView = arr.chunks(5);
}
Should give you
┌ ┐
│ 0 1 2 3 4│
│ 5 6 7 8 9│
│10 11 12 13 14│
│15 16 17 18 19│
└ ┘
whenever you need to access its elements as arr.chunks(5)[1][1
.. 3] --> [6, 7].
@ tastyminerals Thanks for your help on this. These comments,
combined with the others, are making my climb of the D learning
curve much quicker.
I'm not a gitHub fan, but I like the mir functions; and it looks
like I have to download mir before using it.
mir has quite a few .d files..Is there a quick way to download it
?
Re: 2-D array initialization
On Saturday, 1 August 2020 at 22:00:43 UTC, Ali Çehreli wrote: On 8/1/20 12:57 PM, Andy Balba wrote: > On Saturday, 1 August 2020 at 00:08:33 UTC, MoonlightSentinel wrote: >> On Friday, 31 July 2020 at 23:42:45 UTC, Andy Balba wrote: >>> How does one initialize c in D ? >> >> ubyte[3][4] c = [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; > I'm a D newbie. moving over from C/C++, and I'm really finding it hard > to adjusting to D syntax, which I find somewhat cryptic compared to C/C++. That's surprising to me. I came from C++03 year ago but everything in D was much better for me. :) I wanted to respond to your question yesterday and started typing some code but then I decided to ask first: Do you really need a static array? Otherwise, the following is a quite usable 2D array: ubyte[][] c = [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; However, that's quite different from a ubyte[3][4] static array because 'c' above can be represented like the following graph in memory. (Sorry if this is already known to you.) c.ptr --> | .ptr | .ptr | .ptr | .ptr | | | | | . . | --> | 35 | 35 | 35 | 35 | etc. etc. --> | 25 | 25 | 25 | 25 | In other words, each element is reached through 2 dereferences in memory. On the other hand, a static array consists of nothing but the elements in memory. So, a ubyte[3][4] would be the following elements in memory: | 5 | 5 | ... | 35 | 35 | One big difference is that static arrays are value types, meaning that all elements are copied e.g. as arguments during function calls. On the other hand, slices are copied just as fat pointers (ptr+length pair), hence have reference semantics. Here are some ways of initializing a static array. This one is the most natural one: ubyte[3][4] c = [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; Yes, that works! :) Why did you need to cast to begin with? One reason may be you had a value that could not fit in a ubyte so the compiler did not agree. (?) This one casts a 1D array as the desired type: ubyte[3][4] c = *cast(ubyte[3][4]*)(cast(ubyte[])[ 5, 5, 5, 15, 15, 15, 25, 25, 25, 35, 35, 35 ]).ptr; The inner cast is required because 5 etc. are ints by-default. There is std.array.staticArray as well but I haven't used it. Ali Although not detailed in my original question, in my actual app I have array ubyte [1000][3] Big which consists of research data I obtained, and from which I want to randomly select 4 observations to construct ubyte c[ ][ ]. i.e. construct c= [ Big[r1][3], Big[r2][3], Big[r3][3], Big[r4][3] ] where r1, r2, r3 and r4 are 4 random integers in 0..1001 Being a D newbie, my naive way of doing this was to declare c using: ubyte[3][4] c= [ Big[r1][3], Big[r2][3], Big[r3][3], Big[r4][3] ] Obviously, I want to learn how to this the smart D way, but I not smart enough at this point.
Re: 2-D array initialization
On Saturday, 1 August 2020 at 00:08:33 UTC, MoonlightSentinel wrote: On Friday, 31 July 2020 at 23:42:45 UTC, Andy Balba wrote: How does one initialize c in D ? ubyte[3][4] c = [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; none of the statements below works c = cast(ubyte) [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; This is an invalid cast because it tries to coerce the entire literal into an ubyte. Also it would be an assignment instead of an initialization because this is independent of c's declaration. c[0] = ubyte[3] [5, 5, 5] ; c[1] = ubyte[3] [15, 15,15] ; c[2] = ubyte[3] [25, 25,25] ; c[3] = ubyte[3] [35, 35,35] ; A cast is usually specified as `cast(TargetType) value` but not necesseray in this example. Use this instead: c[0] = [5, 5, 5] ; c[1] = [15, 15,15] ; c[2] = [25, 25,25] ; c[3] = [35, 35,35] ; for (int i= 0; i<3; i++) for (int j= 0; i<4; j++) c[i][j]= cast(ubyte)(10*i +j) ; The array indices and the inner loop condition are wrong for (int i= 0; i<3; i++) for (int j= 0; j<4; j++) c[j][i]= cast(ubyte)(10*i +j) ; You could also use foreach-loops, e.g. foreach (j, ref line; c) foreach (i, ref cell; line) cell = cast(ubyte) (10 * i + j); @ MoonlightSentinel: sorry about the typo in for (int i= 0; i<3; i++) for (int j= 0; j<4; j++) I'm a D newbie. moving over from C/C++, and I'm really finding it hard to adjusting to D syntax, which I find somewhat cryptic compared to C/C++. After going thru a D on-line tutorial, I decided D was much better than C/C++, so I began by journey into D by converting one of my less complicated C++ apps. I'm surprised at the enormous amount of time this D-conversion has taken compared to GO conversion of the very same app. Obviously, I need a faster way of climbing the D learning curve, so I would appreciate any suggestions.
2-D array initialization
ubyte[3][4] c ; How does one initialize c in D ? none of the statements below works c = cast(ubyte) [ [5, 5, 5], [15, 15,15], [25, 25,25], [35, 35,35] ]; c[0] = ubyte[3] [5, 5, 5] ; c[1] = ubyte[3] [15, 15,15] ; c[2] = ubyte[3] [25, 25,25] ; c[3] = ubyte[3] [35, 35,35] ; for (int i= 0; i<3; i++) for (int j= 0; i<4; j++) c[i][j]= cast(ubyte)(10*i +j) ;
Re: arrays in srucs
On Friday, 31 July 2020 at 17:26:17 UTC, Paul Backus wrote:
On Friday, 31 July 2020 at 17:02:46 UTC, Andy Balba wrote:
The above code, compiles and runs ok .. but sometimes I get
run runtime errors using the same paradym, which disappear
when I substitute (img.p)[i]
Any explanation for this ?
Can you show an example where it doesn't work?
Copy the code block below into your editor then
Look down at second statement marked "// printf "
when I use () it works fine, but without () it gives run-time
errors
import image_BMP ;
import colorMaps : hsv_colormap, jet_colormap, prism_colormap,
vga_colormap ;
import std.math ;
import std.random ;
import std.stdio ;
int main()
{ int cmapM= 2, cmapJ= 3; // cmap: 0=hsv_colormap,
1=jet_colormap, 2=prism_colormap, 3= vga_colormap
// cmapM, cmapJ = colormap for
Mendelbrot, Julia
const uint W = 1200, H = 800, Bp=3, row_size= W*Bp ; //
fractal width, height, Bytes per pixel
IFImage img ; // fractal image
img.w = W; img.h = H; img.c = ColFmt.RGB; img.pixels = new
ubyte[H*W*3]; // c= color format: 1=Gray 2=Gray+Alpha, 3=RGB
4=RGB +Alpha
// 1200 * 800 *3 = 2.8 MB per image 4 images= 11.2 MB
int max_iterations= 1000;
for (int Y=0; Y< H; ++Y)
{ for (int X=0; X< W; ++X)
{
double cr= 1.5 *(2.0*X /W-1.0) -0.5, ci= (2.0*Y /H
-1.0); // Mendelbrot Fractal constant= (cr, ci)
double nr=0, ni= 0, pr=0, pi = 0;
for (int i= 0; i< max_iterations; i++)
{ pr= nr; pi = ni; nr= pr*pr -pi*pi +cr; ni=
2*pr*pi +ci; // z(real, imag)= (pr,pi), z^2+c (real, imag)=
(nr,ni)
if (((nr*nr) +(ni*ni)) > 4)
{ if (max_iterations != i)
{ double z= sqrt(nr*nr +ni*ni);
int cid = cast(int) (1000.0*log2(1.75 +i
-log2(log2(z)))/ log2(max_iterations));
ubyte[3][4] c= [ hsv_colormap[cid],
jet_colormap[cid], prism_colormap[cid], vga_colormap[cid] ];
//printf("Y%i X%i :\n", Y, X); stdout.flush();
foreach ( p; 0..3 )
{
//printf(">%i %i %i", p, cmapM, Y*row_size +X*Bp +p );
stdout.flush();
img.pixels [ Y*row_size +X*Bp +p ] =
c[p][cmapM] ;
}
}
break;
} } } }
write_image ( "M_fractal.bmp", cast(long) img.w, cast(long)
img.h, img.pixels, cast(long)img.c ) ;
arrays in srucs
I frequently use this paradigm for my image processing apps :
import std.stdio ;
struct S { int a, b; ubyte[] p;
}
void main()
{ S img= S(11,22) ; img.p = new ubyte[5];
foreach (i; 0 .. 5) {
img.p[i]=cast(ubyte)(10+i) ; printf(" sa %d sb %d : %d\n",
img.a, img.b, img.p[i] );
}
}
The above code, compiles and runs ok .. but sometimes I get run
runtime errors using the same paradym, which disappear when I
substitute (img.p)[i]
Any explanation for this ?
is using predSwitch the only way to create to create recursive functions in D ?
,,
