On 10/1/21 12:44 PM, Danny Arends wrote:
Hey all,
Using a modified 3D A* tile searching algorithm, full code see:
https://github.com/DannyArends/CalderaD/blob/master/src/math/search.d
I get the following AssertError, 'sometimes' but not always on running
the code:
mutation.d(2816): Swap: rhs points to lhs.
the first time I hit Phobos is because I call the
std.algorithm.sorting.sort function to sort my open list (just an array
of search node objects);
```
search.openlist.sort!("a.f < b.f")();
```
sneakily f here is a @property function of the object, which just
computes and returns a float:
```
// sum of cumulative cost of this node + predecessors + heuristic
struct Node {
float g; // cost of this node + it's predecessors
float h; // heuristic estimate of distance to goal
@nogc @property float f() nothrow const { return(this.g + this.h); }
}
```
I think your struct is different than this, because this only happens if
aliasing is inside the struct being sorted (i.e. it has pointers). Your
presented struct doesn't have pointers, and the code you linked to is
completely parameterized on the struct type.
If it does have pointers, you are not allowed to swap the values if
either points to each other (or themselves).
-Steve
