Rust argmin: Problems initialising a NelderMead struct (argmin::solver::neldermead::NelderMead)

I get errors when I try to initialise a Nelder Mead struct from the argmin crate.

Here is my code:

use argmin::solver::neldermead::NelderMead;

fn example() {
    let vec_of_parameters = vec![
        vec![1.0],
        vec![2.0],
    ];

    let nm: NelderMead<Vec<f64>, f64> = NelderMead::new(vec_of_parameters);
}

This returns the followin errors:

• the trait argmin_math::ArgminAdd<Vec<f64>, Vec<f64>> is not implemented for Vec<f64>
• the trait argmin_math::ArgminSub<Vec<f64>, Vec<f64>> is not implemented for Vec<f64>
• the trait argmin_math::ArgminMul<_, Vec<f64>> is not implemented for Vec<f64>

I am using argmin version 10.0.0 and ndarray version 0.16.1, and Rust 1.8.3 - thanks

It seems that argmin-math makes supporting Vecs an optional feature. This feature is enabled by default when you depend on argmin-math (see its Cargo.toml), but depending on just argmin by itself doesn’t enable anything at all (because in argmin's Cargo.toml, it specifies default-features = false).

So, if you add argmin-math to your own Cargo.toml,

[dependencies]
argmin = { version = "0.10" }
argmin-math = { version = "0.4" }

then that should add the missing implementations (because you've implicitly asked for argmin-math's default features). Or if you want to be explicit that you need Vec,

[dependencies]
argmin = { version = "0.10" }
argmin-math = { version = "0.4", features = ["vec"] }

The documentation vaguely alludes to this by saying

In order to use argmin, one needs to add both argmin and argmin-math to Cargo.toml: … Via adding argmin-math one can choose which math backend should be available.

but if you ask me, they could stand to be a little more explicit about how it won’t work if you don’t add both.