3 ms·

I would pick the number of non-zeros first, assert that it's non-zero, then continue filling in the values themselves. And probably not with a uniform distribut

I would pick the number of non-zeros first, assert that it's non-zero, then continue filling in the values themselves. And probably not with a uniform distribution. Any algorithm that cares about the number of non-zeros could have non-trivial interactions with their arrangement and count, so picking something that generates non-trivial sparsity (and doesn't just make the array look like white noise) is going to have the best chance of exposing interesting behavior. The tricky part is thinking through how to generate "interesting" patterns, which admittedly I haven't put enough thought into.

dllthomas 2y ago
Ah, yeah, generating for property testing probably doesn't want a uniform distribution. What patterns are interesting will surely depend on what we're doing with the array.
- jgalt212 2y ago
  Indeed, the world is not IID. As such, test cases should not be a uniformly distributed sample of some mathematical distribution.
  - dllthomas 2y ago
    > Indeed, the world is not IID. Right! And even if it were, in the sense that that's what we should expect as real world input, it wouldn't generally be the best distribution for finding bugs.