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Diffstat (limited to 'media/libstagefright/wifi-display/sink/LinearRegression.cpp')
-rw-r--r-- | media/libstagefright/wifi-display/sink/LinearRegression.cpp | 110 |
1 files changed, 0 insertions, 110 deletions
diff --git a/media/libstagefright/wifi-display/sink/LinearRegression.cpp b/media/libstagefright/wifi-display/sink/LinearRegression.cpp deleted file mode 100644 index 8cfce37..0000000 --- a/media/libstagefright/wifi-display/sink/LinearRegression.cpp +++ /dev/null @@ -1,110 +0,0 @@ -/* - * Copyright 2012, The Android Open Source Project - * - * 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. - */ - -//#define LOG_NDEBUG 0 -#define LOG_TAG "LinearRegression" -#include <utils/Log.h> - -#include "LinearRegression.h" - -#include <math.h> -#include <string.h> - -namespace android { - -LinearRegression::LinearRegression(size_t historySize) - : mHistorySize(historySize), - mCount(0), - mHistory(new Point[mHistorySize]), - mSumX(0.0), - mSumY(0.0) { -} - -LinearRegression::~LinearRegression() { - delete[] mHistory; - mHistory = NULL; -} - -void LinearRegression::addPoint(float x, float y) { - if (mCount == mHistorySize) { - const Point &oldest = mHistory[0]; - - mSumX -= oldest.mX; - mSumY -= oldest.mY; - - memmove(&mHistory[0], &mHistory[1], (mHistorySize - 1) * sizeof(Point)); - --mCount; - } - - Point *newest = &mHistory[mCount++]; - newest->mX = x; - newest->mY = y; - - mSumX += x; - mSumY += y; -} - -bool LinearRegression::approxLine(float *n1, float *n2, float *b) const { - static const float kEpsilon = 1.0E-4; - - if (mCount < 2) { - return false; - } - - float sumX2 = 0.0f; - float sumY2 = 0.0f; - float sumXY = 0.0f; - - float meanX = mSumX / (float)mCount; - float meanY = mSumY / (float)mCount; - - for (size_t i = 0; i < mCount; ++i) { - const Point &p = mHistory[i]; - - float x = p.mX - meanX; - float y = p.mY - meanY; - - sumX2 += x * x; - sumY2 += y * y; - sumXY += x * y; - } - - float T = sumX2 + sumY2; - float D = sumX2 * sumY2 - sumXY * sumXY; - float root = sqrt(T * T * 0.25 - D); - - float L1 = T * 0.5 - root; - - if (fabs(sumXY) > kEpsilon) { - *n1 = 1.0; - *n2 = (2.0 * L1 - sumX2) / sumXY; - - float mag = sqrt((*n1) * (*n1) + (*n2) * (*n2)); - - *n1 /= mag; - *n2 /= mag; - } else { - *n1 = 0.0; - *n2 = 1.0; - } - - *b = (*n1) * meanX + (*n2) * meanY; - - return true; -} - -} // namespace android - |