MissionPlanner.MagCalib.doLSQ C# (CSharp) Method

        static double[] doLSQ(List<Tuple<float, float, float>> data, Action<double[], double[], object> fitalgo,
            double[] x)
        {
            double epsg = 0.001;
            double epsf = 0;
            double epsx = 0;
            int maxits = 100;

            alglib.minlmstate state;
            alglib.minlmreport rep;

            alglib.minlmcreatev(data.Count, x, 1, out state);
            alglib.minlmsetcond(state, epsg, epsf, epsx, maxits);

            var t1 = new alglib.ndimensional_fvec(fitalgo);

            alglib.minlmoptimize(state, t1, null, data);

            alglib.minlmresults(state, out x, out rep);

            log.InfoFormat("passes {0}", rep.iterationscount);
            log.InfoFormat("term type {0}", rep.terminationtype);
            log.InfoFormat("njac {0}", rep.njac);
            log.InfoFormat("ncholesky {0}", rep.ncholesky);
            log.InfoFormat("nfunc{0}", rep.nfunc);
            log.InfoFormat("ngrad {0}", rep.ngrad);
            log.InfoFormat("ans {0}", alglib.ap.format(x, 4));

            if (data == datacompass1)
            {
                error = 0;

                foreach (var item in state.fi)
                {
                    error += item;
                }

                error = Math.Round(Math.Sqrt(Math.Abs(error)), 2);
            }


            if (data == datacompass2)
            {
                error2 = 0;

                foreach (var item in state.fi)
                {
                    error2 += item;
                }

                error2 = Math.Round(Math.Sqrt(Math.Abs(error2)), 2);
            }

            if (data == datacompass3)
            {
                error3 = 0;

                foreach (var item in state.fi)
                {
                    error3 += item;
                }

                error3 = Math.Round(Math.Sqrt(Math.Abs(error3)), 2);
            }

            return x;
        }