Mercurial > hg > svcore
view base/LogRange.h @ 335:02d2ad95ea52 spectrogram-cache-rejig
* Get storage advice for each cache in an FFT data server. Allows us to be
more confident about the actual memory situation and cut over from memory
to disc part way through an FFT calculation if necessary. StorageAdviser
is now a bit too optimistic though (it's too keen to allocate large numbers
of small blocks in memory).
author | Chris Cannam |
---|---|
date | Tue, 13 Nov 2007 13:54:10 +0000 |
parents | 2268963dabd1 |
children | 1405f4a2caf3 |
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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. */ #ifndef _LOG_RANGE_H_ #define _LOG_RANGE_H_ class LogRange { public: /** * Map a linear range onto a logarithmic range. min and max are * passed as the extents of the linear range and returned as the * extents of the logarithmic range. thresh is the minimum value * for the log range, to be used if the linear range spans zero. */ static void mapRange(float &min, float &max, float thresh = -10); /** * Map a value onto a logarithmic range. This just means taking * the base-10 log of the absolute value, or using the threshold * value if the absolute value is zero. */ static float map(float value, float thresh = -10); /** * Map a value from the logarithmic range back again. This just * means taking the value'th power of ten. */ static float unmap(float value); }; #endif