On Tuesday, 11 June 2024 at 17:15:07 UTC, Vinod K Chandran wrote:

Btw are you going to use PyD or doing everything manually from scratch?

On Tuesday, 11 June 2024 at 17:15:07 UTC, Vinod K Chandran wrote:

On the second point, I would be interested in hearing what you find out. In general, I have not had any luck with speeding things up inside loops using manual memory management. The only that's worked is avoiding allocations and reusing already allocated memory.

You're splitting things into GC-allocated memory and manually managed memory. There's also SafeRefCounted, which handles the malloc and free for you.

A SafeRefCounted example with main marked @nogc:

import std;
import core.stdc.stdlib;

struct Foo {
  double[] data;
  double * ptr;
  alias data this;

  @nogc this(int n) {
    ptr = cast(double*) malloc(n*double.sizeof);
    data = ptr[0..n];
    printf("Data has been allocated\n");
  }

  @nogc ~this() {
    free(ptr);
    printf("Data has been freed\n");
  }
}

@nogc void main() {
  auto foo = SafeRefCounted!Foo(3);
  foo[0..3] = 1.5;
  printf("%f %f %f\n", foo[0], foo[1], foo[2]);
}

On Wednesday, 12 June 2024 at 01:35:26 UTC, monkyyy wrote:

How's that even possible ? AFAIK, we need heap allocated memory in order to make GUI lib as a DLL. So creating things in heap and modify it, that's the nature of my project.

On Wednesday, 12 June 2024 at 09:44:05 UTC, DrDread wrote:

Thanks for the suggestion. Let me check that idea.

On Wednesday, 12 June 2024 at 10:16:26 UTC, Sergey wrote:

Does PyD active now ? I didn't tested it. My approach is using "ctypes" library with my dll. Ctypes is the fastes FFI in my experience. I tested Cython, Pybind11 and CFFI. But None can beat the speed of ctypes. Currently the fastest experiments were the dlls created in Odin & C3. Both are non-GC languages.

On Wednesday, 12 June 2024 at 15:21:22 UTC, bachmeier wrote:

Thanks, I have read about the possibilities of "using malloc and free from D" in some other post. I think I should need to check that.

On Wednesday, 12 June 2024 at 15:33:39 UTC, bachmeier wrote:

Thanks for the sample. It looks tempting! Let me check that.

On Wednesday, 12 June 2024 at 15:33:39 UTC, bachmeier wrote:

import std;
import core.stdc.stdlib;

struct Foo {
  double[] data;
  double * ptr;
  alias data this;

  @nogc this(int n) {
    ptr = cast(double*) malloc(n*double.sizeof);
    data = ptr[0..n];
    printf("Data has been allocated\n");
  }
 }

Why not just use ptr ? Why did you data with ptr ?

On Wednesday, 12 June 2024 at 18:36:26 UTC, Vinod K Chandran wrote:

import std;
import core.stdc.stdlib;

struct Foo {
  double[] data;
  double * ptr;
  alias data this;

  @nogc this(int n) {
    ptr = cast(double*) malloc(n*double.sizeof);
    data = ptr[0..n];
    printf("Data has been allocated\n");
  }
 }

Try foo[10] = 1.5 and foo.ptr[10] = 1.5. The first correctly throws an out of bounds error. The second gives Segmentation fault (core dumped).