intro to ann 

use ndarray::{arr2, Array1};

#[derive(Default)]
struct Neuron {
    w: Array1<f32>,
    b: f32,
}

impl Neuron {
    // fn new_weight(old_weight:Array1<f32>) -> Array1<f32> {
    // }

    fn activate(&self, x:Array1<f32>) -> i8 {
        let y:i8 = if self.w.dot(&x) + self.b > 0.0 { 1 } else { -1 };

        println!("(w:{} * x:{}) + b:{} = y:{}", self.w, x, self.b, y);
        return y;
    }
}

fn main() {
    let n: Neuron = Default::default();

    let x = arr2(&[[-1.0, 1.0],
                   [0.0, -1.0],
                   [10.0, 1.0],]);

    n.activate(x[0]);
    // n.activate(x[1]);
    // n.activate(x[2]);
}

__END__
error[E0277]: the trait bound `{integer}: NdIndex<Dim<[usize; 2]>>` is not satisfied
  --> src/main.rs:28:16
   |
28 |     n.activate(x[0]);
   |                ^^^^ the trait `NdIndex<Dim<[usize; 2]>>` is not implemented for `{integer}`
   |
   = help: the following implementations were found:
             <&'a Dim<IxDynImpl> as NdIndex<Dim<IxDynImpl>>>
             <&'a [usize] as NdIndex<Dim<IxDynImpl>>>
             <() as NdIndex<Dim<[usize; 0]>>>
             <(usize, usize) as NdIndex<Dim<[usize; 2]>>>
           and 27 others
   = note: required because of the requirements on the impl of `std::ops::Index<{integer}>` for `ArrayBase<OwnedRepr<{float}>, Dim<[usize; 2]>>`

error[E0308]: mismatched types
  --> src/main.rs:28:16
   |
28 |     n.activate(x[0]);
   |                ^^^^ expected struct `ArrayBase`, found floating-point number
   |
   = note: expected struct `ArrayBase<OwnedRepr<f32>, Dim<[usize; 1]>>`
                found type `{float}`