165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn/* 265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * Copyright (C) 2011 The Android Open Source Project 365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * 465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * Licensed under the Apache License, Version 2.0 (the "License"); 565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * you may not use this file except in compliance with the License. 665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * You may obtain a copy of the License at 765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * 865953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * http://www.apache.org/licenses/LICENSE-2.0 965953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * 1065953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * Unless required by applicable law or agreed to in writing, software 1165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * distributed under the License is distributed on an "AS IS" BASIS, 1265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 1365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * See the License for the specific language governing permissions and 1465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn * limitations under the License. 1565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn */ 1665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 1765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn#include "core/statistics.h" 1865953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 1965953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn#include <math.h> 2065953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 2165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Rennnamespace android { 2265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Rennnamespace filterfw { 2365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 2465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius RennIncrementalGaussian::IncrementalGaussian() 2565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn : n_(0), 2665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn sum_x_(0.0f), 2765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn sum_x2_(0.0f), 2865953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn mean_(0.0f), 2965953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn var_(0.0f), 3065953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn exp_denom_(0.0f), 3165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn pdf_denom_(0.0f) { 3265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} 3365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 3465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Rennvoid IncrementalGaussian::Add(float value) { 3565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn ++n_; 3665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn sum_x_ += value; 3765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn sum_x2_ += value * value; 3865953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 3965953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn mean_ = sum_x_ / n_; 4065953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn var_ = sum_x2_ / n_ - mean_ * mean_; 4165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 4265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn exp_denom_ = 2.0f * var_; 4365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn pdf_denom_ = sqrtf(M_PI * exp_denom_); 4465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} 4565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 4665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Rennfloat IncrementalGaussian::Std() const { 4765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn return sqrtf(var_); 4865953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} 4965953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 5065953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Rennfloat IncrementalGaussian::Pdf(float value) const { 5165953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn if (var_ == 0.0f) { return n_ > 0 ? value == mean_ : 0.0f; } 5265953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn const float diff = value - mean_; 5365953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn return expf(-diff * diff / exp_denom_) / pdf_denom_; 5465953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} 5565953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn 5665953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} // namespace filterfw 5765953da4636fbf5f0a24b8f5f2b5fa7d76ff13d9Marius Renn} // namespace android 58