Function smith

src/plots/smith/helpers.js:11–19

(a)

// adapted from Mike Bostock's https://observablehq.com/@mbostock/smith-chart
function smith(a) {
    var R = a[0];
    var X = a[1];

    if(!isFinite(R) || !isFinite(X)) return [1, 0];

    var D = (R + 1) * (R + 1) + X * X;
    return [(R * R + X * X - 1) / D, 2 * X / D];
}

function transform(subplot, a) {
    var x = a[0];