傅里叶变换

1、引入MathNet.Numerics。

2、

var b = new double[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
var a = b.Select(d => new Complex(d, 0)).ToArray();
Transform.FourierForward(a);
var c = a.Select(d => d.Magnitude).ToArray();