Runtime dynamic size array/list/vector of arbitrary type in callable/kernel

[MaxwellFang]

Is your feature request related to a problem? Please describe.
I want to record all the vertex in the path. The vertex is a struct which consists of all DSL variables. However I didn't find a good way to record that in the callable as it seems like the size and the index should be determined at "compile time". Is there any suggested way of doing that?

Describe the solution you'd like

Array<Vertex> vertices(n);
...
$for(i, max_depth) {
    auto v = vertices[i];
    v.position = make_float3(1.0f);
}
...

Describe alternatives you've considered
I have tried linked list by using a pointer in Vertex, but this does not seem right as DSL have not actually run the code. Any suggestion on how to properly implement that will also be helpful.

[Mike-Leo-Smith]

Hi, @MaxwellFang

You may use Local<T> in <luisa/dsl/local.h> which can be constructed with runtime-specified lengths. The element type T can be any DSL type, i.e., scalars, vectors, matrices, or POD structures reflected by LUISA_STRUCT.

Example:

namespace some {
struct Test {
  float a;
  uint2 b;
};
} // namespace some

// reflect the plain C structure
LUISA_STRUCT(some::Test, a, b) {};

int main() {
  uint n = some_runtime_value();
  Kernel1D kernel = [] {
    Local<Test> x{n}; // construct an array with n elements of struct Test
  };
}

[MaxwellFang]

Hi, @MaxwellFang

You may use Local<T> in <luisa/dsl/local.h> which can be constructed with runtime-specified lengths. The element type T can be any DSL type, i.e., scalars, vectors, matrices, or POD structures reflected by LUISA_STRUCT.

Example:

namespace some {
struct Test {
  float a;
  uint2 b;
};
} // namespace some

// reflect the plain C structure
LUISA_STRUCT(some::Test, a, b) {};

int main() {
  uint n = some_runtime_value();
  Kernel1D kernel = [] {
    Local<Test> x{n}; // construct an array with n elements of struct Test
  };
}

My struct is something like

struct Vertex {
    Float3 position;
    SampledSpectrum beta;
    ....
};

which the variables DSL types but the struct itself is not reflected by LUISA_STRUCT. So I was wondering if that would be the same.