using std.algorithm.topN with std.range.zip fails with undefined swap

[Nikhil Padmanabhan]

Hi,

Trying to compile :

import std.stdio, std.range, std.algorithm;

void main() {
auto a = [2.0,1.0,3.0];
struct Point {
double x;
}
auto b = [Point(4.0), Point(5.0), Point(6.0)];

topN!(a[0]  b[0])(zip(a,b),1);
//sort!(a[0]  b[0])(zip(a,b));

writeln(a,b);
}


std/algorithm.d(8225): Error: template std.algorithm.swap does 
not match any function template declaration.


Swapping out topN with sort works just fine. I assume both sort 
and topN use swap, is there a reason this doesn't work with topN?


Thanks in advance,

-- Nikhil

using std.algorithm.topN with std.range.zip fails with undefined swap

[Nikhil Padmanabhan]

(apologies in advance if this posts multiple times, I messed up the sending
email address the first time).

Hi,

Trying to compile :

import std.stdio, std.range, std.algorithm;

void main() {
auto a = [2.0,1.0,3.0];
struct Point {
double x;
}
auto b = [Point(4.0), Point(5.0), Point(6.0)];

topN!(a[0]  b[0])(zip(a,b),1);
//sort!(a[0]  b[0])(zip(a,b));

writeln(a,b);
}


std/algorithm.d(8225): Error: template std.algorithm.swap does not match
any function template declaration.

Swapping out topN with sort works just fine. I assume both sort and topN
use swap, is there a reason this doesn't work with topN?

Thanks in advance,

-- Nikhil


-
Nikhil Padmanabhan
nikhil.padmanab...@yale.edu

segfault when using std.parallelism and std.process.executeShell

[Nikhil Padmanabhan]

Hi,

The following code dies with a segfault :

import std.stdio, std.parallelism, std.process;

void main() {
auto a=[hello,world,goodbye];
foreach(s; parallel(a,1)) {
auto ls=executeShell(echo ~s);
writeln(ls.output);
}
}

both in ldc and dmd. Removing either the parallel or running 
something other than executeShell (eg. just doing a writeln) 
works, which suggests to me that it's something about the way 
executeShell is interacting with parallel.


Pulling it up in lldb, I get :
* thread #2: tid = 0x16738e6, 0x000100039198 
test`D3std7process7environFNbNdNeZxPPa + 20, stop reason = 
EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x000100039198 
test`D3std7process7environFNbNdNeZxPPa + 20


Any thoughts on what might be going wrong? Is executeShell 
somehow not threadsafe?


Thanks!
-- Nikhil

Compile error using synchronized in ldc (but not dmd)

[Nikhil Padmanabhan]

Hello,

The following code snippet fails to compile on ldc2 (0.12.1), but 
successfully compiles on dmd 2.064.2 :


struct Particle {
double x,y,z,w,x2;
this(double[] arr) {
x = arr[0]; y = arr[1]; z=arr[2]; w=arr[3];
x2 = x*x + y*y + z*z;
}
}

synchronized class SyncArray {
private Particle[] buf;

void push(Particle[] arr1) {
buf.length = arr1.length;
buf[] = arr1[];
}

Particle[] pop() {
auto _tmp = new Particle[buf.length];
_tmp[] = buf[];
buf = null;
return _tmp;
}
}

The error message in ldc2 :
test.d(14): Error: cannot implicitly convert expression (arr1[]) 
of type Particle[] to const(shared(Particle)[])
test.d(19): Error: cannot implicitly convert expression 
(this.buf[]) of type shared(Particle)[] to const(Particle[])


What am I doing wrong here?

Thanks in advance!
-- Nikhil

P.S. I've been enjoying coding in D a lot -- many thanks to the 
entire D community!

Re: Compile error using synchronized in ldc (but not dmd)

[Nikhil Padmanabhan]

Just a quick follow-up : replacing the array operation by a 
foreach works around this issue, but I don't understand why it 
failed in the first place.



On Monday, 9 December 2013 at 04:26:01 UTC, Nikhil Padmanabhan 
wrote:

Hello,

The following code snippet fails to compile on ldc2 (0.12.1), 
but successfully compiles on dmd 2.064.2 :


struct Particle {
double x,y,z,w,x2;
this(double[] arr) {
x = arr[0]; y = arr[1]; z=arr[2]; w=arr[3];
x2 = x*x + y*y + z*z;
}
}

synchronized class SyncArray {
private Particle[] buf;

void push(Particle[] arr1) {
buf.length = arr1.length;
buf[] = arr1[];
}

Particle[] pop() {
auto _tmp = new Particle[buf.length];
_tmp[] = buf[];
buf = null;
return _tmp;
}
}

The error message in ldc2 :
test.d(14): Error: cannot implicitly convert expression 
(arr1[]) of type Particle[] to const(shared(Particle)[])
test.d(19): Error: cannot implicitly convert expression 
(this.buf[]) of type shared(Particle)[] to const(Particle[])


What am I doing wrong here?

Thanks in advance!
-- Nikhil

P.S. I've been enjoying coding in D a lot -- many thanks to the 
entire D community!