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KDATA_STDDEV_ALLOC(3) Library Functions Manual KDATA_STDDEV_ALLOC(3) NAME kdata_stddev_alloc -- allocate standard deviation data for plotting LIBRARY library "libkplot" SYNOPSIS #include <cairo.h> #include <kplot.h> struct kdata * kdata_stddev_alloc(struct kdata *source); DESCRIPTION The kdata_stddev_alloc creates a reference-counted data sources for kplot(3). It attaches to zero or more existing data sources and, when they update their values, tracks the standard deviation (via the unbi- ased sample variance) of sequence of updated values. It attaches to zero or more existing data sources and, when they update their values per-index, tracks the standard deviation (via the unbiased sample variance) of the sequence of updated values. Thus, if a stan- dard deviation data source is attached to two sources, its y-value for pair zero will reflect the standard deviation from the mean of all val- ues set to pair zero's y-value in the sources. Note that the indexing is absolute: if attached to a bucket or histogram, pair index zero refers to the first internal data storage, not storage mapped from the bucket or histogram. If source is not NULL, the internal buffer is initialised to the size of the source and all of its x values. The standard deviation is ini- tialised to zero with zero updates. Otherwise, the internal buffer is sized to zero. Further data sources may be attached with kdata_stddev_attach(3). RETURN VALUES kdata_stddev_alloc returns NULL if memory allocation failed. SEE ALSO kdata_stddev_attach(3), kplot(3) Donald E. Knuth, The Art of Computer Programming: Seminumerical Algorithms, 3rd Edition, Addison-Wesley, Volume 2, 232, Boston, 1998. CAVEATS Each standard deviation bucket can process a maximum number of SIZE_MAX updates. FreeBSD ports 15.quarterly January 22, 2015 KDATA_STDDEV_ALLOC(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | CAVEATS
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