Mercurial > hg > svcore
view base/LogRange.cpp @ 1008:d9e0e59a1581
When using an aggregate model to pass data to a transform, zero-pad the shorter input to the duration of the longer rather than truncating the longer. (This is better behaviour for e.g. MATCH, and in any case the code was previously truncating incorrectly and ending up with garbage data at the end.)
author | Chris Cannam |
---|---|
date | Fri, 14 Nov 2014 13:51:33 +0000 |
parents | 1424aa29ae95 |
children | cc27f35aa75c |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This file copyright 2006 Chris Cannam. 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. See the file COPYING included with this distribution for more information. */ #include "LogRange.h" #include "system/System.h" #include <algorithm> #include <iostream> #include <cmath> void LogRange::mapRange(float &min, float &max, float logthresh) { if (min > max) std::swap(min, max); if (max == min) max = min + 1; // SVDEBUG << "LogRange::mapRange: min = " << min << ", max = " << max << endl; if (min >= 0.f) { max = log10f(max); // we know max != 0 if (min == 0.f) min = std::min(logthresh, max); else min = log10f(min); // SVDEBUG << "LogRange::mapRange: positive: min = " << min << ", max = " << max << endl; } else if (max <= 0.f) { min = log10f(-min); // we know min != 0 if (max == 0.f) max = std::min(logthresh, min); else max = log10f(-max); std::swap(min, max); // SVDEBUG << "LogRange::mapRange: negative: min = " << min << ", max = " << max << endl; } else { // min < 0 and max > 0 max = log10f(std::max(max, -min)); min = std::min(logthresh, max); // SVDEBUG << "LogRange::mapRange: spanning: min = " << min << ", max = " << max << endl; } if (min == max) min = max - 1; } float LogRange::map(float value, float thresh) { if (value == 0.f) return thresh; return log10f(fabsf(value)); } float LogRange::unmap(float value) { return powf(10.0, value); } static float sd(const std::vector<float> &values, size_t start, size_t n) { float sum = 0.f, mean = 0.f, variance = 0.f; for (size_t i = 0; i < n; ++i) { sum += values[start + i]; } mean = sum / n; for (size_t i = 0; i < n; ++i) { float diff = values[start + i] - mean; variance += diff * diff; } variance = variance / n; return sqrtf(variance); } bool LogRange::useLogScale(std::vector<float> values) { // Principle: Partition the data into two sets around the median; // calculate the standard deviation of each set; if the two SDs // are very different, it's likely that a log scale would be good. if (values.size() < 4) return false; std::sort(values.begin(), values.end()); size_t mi = values.size() / 2; float sd0 = sd(values, 0, mi); float sd1 = sd(values, mi, values.size() - mi); SVDEBUG << "LogRange::useLogScale: sd0 = " << sd0 << ", sd1 = " << sd1 << endl; if (sd0 == 0 || sd1 == 0) return false; // I wonder what method of determining "one sd much bigger than // the other" would be appropriate here... if (std::max(sd0, sd1) / std::min(sd0, sd1) > 10.f) return true; else return false; }