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https://github.com/GoldenCheetah/GoldenCheetah.git
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64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
/*
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* Copyright (c) 2010 Mark Liversedge (liversedge@gmail.com)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <math.h>
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#include <float.h>
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#include "LTMTrend.h"
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#include <QDebug>
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LTMTrend::LTMTrend(double *xdata, double *ydata, int count) :
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minX(0.0), maxX(0.0), minY(0.0), maxY(0.0),
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points(0.0), sumX(0.0), sumY(0.0), sumXsquared(0.0),
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sumYsquared(0.0), sumXY(0.0), a(0.0), b(0.0)
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{
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if (count <= 2) return;
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for (int i = 0; i < count; i++) {
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// ignore zero points
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if (ydata[i] == 0.00) continue;
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points++;
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sumX += xdata[i];
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sumY += ydata[i];
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sumXsquared += xdata[i] * xdata[i];
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sumYsquared += ydata[i] * ydata[i];
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sumXY += xdata[i] * ydata[i];
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}
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if (fabs( double(points) * sumXsquared - sumX * sumX) > DBL_EPSILON) {
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b = ( double(points) * sumXY - sumY * sumX) /
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( double(points) * sumXsquared - sumX * sumX);
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a = (sumY - b * sumX) / double(points);
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double r = ( double(points) * sumXY - sumY * sumX) /
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sqrt(( double(points) * sumXsquared - sumX * sumX) * ( double(points) * sumYsquared - sumY * sumY));
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double sx = b * ( sumXY - sumX * sumY / double(points) );
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double sy2 = sumYsquared - sumY * sumY / double(points);
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double sy = sy2 - sx;
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double coefD = sx / sy2;
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double coefC = sqrt(coefD);
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double stdError = sqrt(sy / double(points - 2));
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qDebug() << coefD << coefC << stdError << r;
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}
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}
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