public NDview <Type> Func(NDview <Type> X) => ND.Gte(X, ND.Zeros <Type>(1)).Cast <Type>() * X;
public NDview <Type> Grad(NDview <Type> X) => ND.Gte(X, ND.Zeros <Type>(1)).Cast <Type>();
public NDview <Type> Grad(NDview <Type> X) => ND.DSigmoid(X);
public NDview <Type> Func(NDview <Type> X) => ND.Sigmoid(X);
public NDview <Type> Grad(NDview <Type> X) => ND.DTanh(X);
public NDview <Type> Func(NDview <Type> X) => ND.Tanh(X);