Group pj_math¶
- group pj_math
Provides common mathematics constants and operations, and also standard statistics calculation (min, max, mean, standard deviation). Statistics calculation is done in realtime (statistics state is updated on time each new sample comes).
Defines
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PJ_PI¶
Mathematical constants
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PJ_1_PI¶
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PJ_ABS(x)¶
Mathematical macro
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PJ_MAX(x, y)¶
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PJ_MIN(x, y)¶
Functions
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unsigned pj_isqrt(unsigned i)¶
Calculate integer square root of an integer.
- Parameters
i – Integer to be calculated.
- Returns
Square root result.
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void pj_math_stat_init(pj_math_stat *stat)¶
Initialize statistics state.
- Parameters
stat – Statistic state.
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void pj_math_stat_update(pj_math_stat *stat, int val)¶
Update statistics state as a new sample comes.
- Parameters
stat – Statistic state.
val – The new sample data.
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unsigned pj_math_stat_get_stddev(const pj_math_stat *stat)¶
Get the standard deviation of specified statistics state.
- Parameters
stat – Statistic state.
- Returns
The standard deviation.
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void pj_math_stat_set_stddev(pj_math_stat *stat, unsigned dev)¶
Set the standard deviation of statistics state. This is useful when the statistic state is operated in ‘read-only’ mode as a storage of statistical data.
- Parameters
stat – Statistic state.
dev – The standard deviation.
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struct pj_math_stat¶
- #include <math.h>
This structure describes statistics state.
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PJ_PI¶