Classifier.StdDev Method

function StdDev(const a: array of double; Mean: double): double;

Compute standard deviation.

Returns: double

Remarks:

Compute standard deviation from the a array, if the mean value of the a array is Mean.

Examples

var a: Matrix;
    c: double;
    aMean: double;
begin
    a := [[1,2],[3,4]];
    aMean := a.Mean;
    c := a.StdDev(aMean); //if both Mean and StdDev are required this is faster
    // c := a.StdDev; //this is an alternative.
end;

var
    a: Matrix;
    result: double;
begin
    a := [[1.0, 2.0], [3.0, 4.0]];
    result := a.StdDev;
    if Abs(result - 1.29099444873581) > 1e-10 then
        raise Exception.Create('Matrix.StdDev: expected 1.29099444873581, got ' + result.ToString);
end;