From 81581f9719bc56f01d5aa08952671d65fda9867a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 8 May 2023 18:27:08 +0200 Subject: Merging upstream version 1.39.0. Signed-off-by: Daniel Baumann --- web/api/queries/stddev/stddev.c | 116 +--------------------------------------- 1 file changed, 2 insertions(+), 114 deletions(-) (limited to 'web/api/queries/stddev/stddev.c') diff --git a/web/api/queries/stddev/stddev.c b/web/api/queries/stddev/stddev.c index 92a67b42d..8f5431194 100644 --- a/web/api/queries/stddev/stddev.c +++ b/web/api/queries/stddev/stddev.c @@ -6,123 +6,11 @@ // ---------------------------------------------------------------------------- // stddev -// this implementation comes from: -// https://www.johndcook.com/blog/standard_deviation/ - -struct grouping_stddev { - long count; - NETDATA_DOUBLE m_oldM, m_newM, m_oldS, m_newS; -}; - -void grouping_create_stddev(RRDR *r, const char *options __maybe_unused) { - r->internal.grouping_data = onewayalloc_callocz(r->internal.owa, 1, sizeof(struct grouping_stddev)); -} - -// resets when switches dimensions -// so, clear everything to restart -void grouping_reset_stddev(RRDR *r) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; - g->count = 0; -} - -void grouping_free_stddev(RRDR *r) { - onewayalloc_freez(r->internal.owa, r->internal.grouping_data); - r->internal.grouping_data = NULL; -} - -void grouping_add_stddev(RRDR *r, NETDATA_DOUBLE value) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; - - g->count++; - - // See Knuth TAOCP vol 2, 3rd edition, page 232 - if (g->count == 1) { - g->m_oldM = g->m_newM = value; - g->m_oldS = 0.0; - } - else { - g->m_newM = g->m_oldM + (value - g->m_oldM) / g->count; - g->m_newS = g->m_oldS + (value - g->m_oldM) * (value - g->m_newM); - - // set up for next iteration - g->m_oldM = g->m_newM; - g->m_oldS = g->m_newS; - } -} - -static inline NETDATA_DOUBLE mean(struct grouping_stddev *g) { - return (g->count > 0) ? g->m_newM : 0.0; -} - -static inline NETDATA_DOUBLE variance(struct grouping_stddev *g) { - return ( (g->count > 1) ? g->m_newS/(NETDATA_DOUBLE)(g->count - 1) : 0.0 ); -} -static inline NETDATA_DOUBLE stddev(struct grouping_stddev *g) { - return sqrtndd(variance(g)); -} - -NETDATA_DOUBLE grouping_flush_stddev(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; - - NETDATA_DOUBLE value; - - if(likely(g->count > 1)) { - value = stddev(g); - - if(!netdata_double_isnumber(value)) { - value = 0.0; - *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY; - } - } - else if(g->count == 1) { - value = 0.0; - } - else { - value = 0.0; - *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY; - } - - grouping_reset_stddev(r); - - return value; -} - -// https://en.wikipedia.org/wiki/Coefficient_of_variation -NETDATA_DOUBLE grouping_flush_coefficient_of_variation(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; - - NETDATA_DOUBLE value; - - if(likely(g->count > 1)) { - NETDATA_DOUBLE m = mean(g); - value = 100.0 * stddev(g) / ((m < 0)? -m : m); - - if(unlikely(!netdata_double_isnumber(value))) { - value = 0.0; - *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY; - } - } - else if(g->count == 1) { - // one value collected - value = 0.0; - } - else { - // no values collected - value = 0.0; - *rrdr_value_options_ptr |= RRDR_VALUE_EMPTY; - } - - grouping_reset_stddev(r); - - return value; -} - - /* * Mean = average * NETDATA_DOUBLE grouping_flush_mean(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; + struct grouping_stddev *g = (struct grouping_stddev *)r->grouping.grouping_data; NETDATA_DOUBLE value; @@ -149,7 +37,7 @@ NETDATA_DOUBLE grouping_flush_mean(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options * It is not advised to use this version of variance directly * NETDATA_DOUBLE grouping_flush_variance(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) { - struct grouping_stddev *g = (struct grouping_stddev *)r->internal.grouping_data; + struct grouping_stddev *g = (struct grouping_stddev *)r->grouping.grouping_data; NETDATA_DOUBLE value; -- cgit v1.2.3