mirror of
https://github.com/Relintai/pandemonium_engine.git
synced 2024-12-29 15:17:11 +01:00
65 lines
1.8 KiB
C++
65 lines
1.8 KiB
C++
/*
|
|
* Copyright 2015 The Etc2Comp Authors.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "EtcConfig.h"
|
|
#include "EtcMath.h"
|
|
|
|
namespace Etc
|
|
{
|
|
|
|
// ----------------------------------------------------------------------------------------------------
|
|
// calculate the line that best fits the set of XY points contained in a_afX[] and a_afY[]
|
|
// use a_fSlope and a_fOffset to define that line
|
|
//
|
|
bool Regression(float a_afX[], float a_afY[], unsigned int a_Points,
|
|
float *a_fSlope, float *a_fOffset)
|
|
{
|
|
float fPoints = (float)a_Points;
|
|
|
|
float fSumX = 0.0f;
|
|
float fSumY = 0.0f;
|
|
float fSumXY = 0.0f;
|
|
float fSumX2 = 0.0f;
|
|
|
|
for (unsigned int uiPoint = 0; uiPoint < a_Points; uiPoint++)
|
|
{
|
|
fSumX += a_afX[uiPoint];
|
|
fSumY += a_afY[uiPoint];
|
|
fSumXY += a_afX[uiPoint] * a_afY[uiPoint];
|
|
fSumX2 += a_afX[uiPoint] * a_afX[uiPoint];
|
|
}
|
|
|
|
float fDivisor = fPoints*fSumX2 - fSumX*fSumX;
|
|
|
|
// if vertical line
|
|
if (fDivisor == 0.0f)
|
|
{
|
|
*a_fSlope = 0.0f;
|
|
*a_fOffset = 0.0f;
|
|
return true;
|
|
}
|
|
|
|
*a_fSlope = (fPoints*fSumXY - fSumX*fSumY) / fDivisor;
|
|
*a_fOffset = (fSumY - (*a_fSlope)*fSumX) / fPoints;
|
|
|
|
return false;
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------------------------------
|
|
//
|
|
|
|
} // namespace Etc
|