mirror of
https://github.com/GoldenCheetah/GoldenCheetah.git
synced 2026-02-13 16:18:42 +00:00
8e3ec70a30
Added a quadratic least squares trend line for the LTMplot as the linear regression was generally too blunt. This is a hack to get the code into the repo -- will know work on refining the LTMPlot settings to enable users to specify the kind of trend line they want. The new trend line might also be useful for other curve fitting functions (e.g. realtime virtual power curve, a peak power chart by cadence/pedal speed).
52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
/*
|
|
* Copyright (c) 2010 Mark Liversedge (liversedge@gmail.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the Free
|
|
* Software Foundation; either version 2 of the License, or (at your option)
|
|
* any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc., 51
|
|
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <float.h>
|
|
#include "LTMTrend.h"
|
|
|
|
#include <QDebug>
|
|
|
|
LTMTrend::LTMTrend(double *xdata, double *ydata, int count) :
|
|
minX(0.0), maxX(0.0), minY(0.0), maxY(0.0),
|
|
points(0.0), sumX(0.0), sumY(0.0), sumXsquared(0.0),
|
|
sumYsquared(0.0), sumXY(0.0), a(0.0), b(0.0)
|
|
{
|
|
if (count <= 2) return;
|
|
|
|
for (int i = 0; i < count; i++) {
|
|
|
|
// ignore zero points
|
|
if (ydata[i] == 0.00) continue;
|
|
|
|
points++;
|
|
sumX += xdata[i];
|
|
sumY += ydata[i];
|
|
sumXsquared += xdata[i] * xdata[i];
|
|
sumYsquared += ydata[i] * ydata[i];
|
|
sumXY += xdata[i] * ydata[i];
|
|
}
|
|
|
|
if (fabs( double(points) * sumXsquared - sumX * sumX) > DBL_EPSILON) {
|
|
b = ( double(points) * sumXY - sumY * sumX) /
|
|
( double(points) * sumXsquared - sumX * sumX);
|
|
a = (sumY - b * sumX) / double(points);
|
|
}
|
|
}
|
|
|