ndarray_rand: random_using() compilation error

[quietlychris]

Hello,

I've been working on creating a reproducible random array for testing variations on a neural network architecture, and came across a bit of an issue with trying to instantiate an Array using the Isaac64 RNG, which seems like it should be supported by the crate. Per the docs, I tried building the listed example in a stand-alone project, with the following in main.rs

use ndarray::Array;
use ndarray_rand::RandomExt;
use ndarray_rand::rand::SeedableRng;
use ndarray_rand::rand_distr::Uniform;
use rand_isaac::isaac64::Isaac64Rng;

fn main() {
    // Get a seeded random number generator for reproducibility (Isaac64 algorithm)
    let seed = 42;
    let mut rng = Isaac64Rng::seed_from_u64(seed);

    // Generate a random array using `rng`
    let a = Array::random_using((2, 5), Uniform::new(0., 10.), &mut rng);
    println!("{:8.4}", a);
}

and this in my Cargo.toml file.

[dependencies]
ndarray = "0.13"
ndarray-rand = "0.13"
rand = "0.8"
rand_isaac = "0.3"

However, each time I receive

error[E0599]: no function or associated item named `random_using` found for struct `ArrayBase<OwnedRepr<_>, _>` in the current scope
  --> src/main.rs:13:20
   |
13 |     let a = Array::random_using((2, 5), Uniform::new(0., 10.), &mut rng);
   |                    ^^^^^^^^^^^^ function or associated item not found in `ArrayBase<OwnedRepr<_>, _>`

I've tested this behavior using both rustc 1.48.0 (7eac88abb 2020-11-16) and rustc 1.51.0-nightly (0b644e419 2020-12-26). I didn't see a test in ndarray/ndarray-rand/tests/test.rs that covers the random_using() function, which means this error may have been missed by CI, although it's certainly possible that I may have missed something.

I'd be happy to test any corrections, and I have find the time, I may be able to dig into this an submit a PR fixing, although I have a few other things on my plate before I can get there. Thanks, and hope your holidays have been well!

[relf]

I think I've met the same problem. I have to stick to ndarray-rand="0.11" to make it work (I use ndarray="0.13" as well).

[jturner314]

I think the issue is incompatible versions, as @relf indicated. For ndarray-rand 0.13, you need to use ndarray 0.14, rand 0.8, and rand_distr 0.4. (See the dependencies in the right column on the crates.io page for ndarray-rand 0.13.) If you want to stay on ndarray 0.13.0 for now, the latest version of ndarray-rand that supports it is ndarray-rand 0.11.0.

Hopefully, the error message for this type of thing will be improved in the future. (See rust-lang/rust#22750.) In the meantime, it would be worth adding a note about the correct version of ndarray to the main page of the docs, near where it says, "ndarray-rand depends on rand 0.8."

[quietlychris]

Ah, gotcha. I was hoping to keep using ndarray 0.13.* until 0.15 gets released, since it from the threads it seems the plan was to have that happen relatively soon, but I can just move up to 0.14 in the interim.

At least on my system, using ndarray-rand = "0.13", ndarray = "0.14 works, but I get an error if I try ndarray-rand = "0.11", ndarray = "0.13".