Merging upstream version 1.39.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 116 insertions, 122 deletions

diff --git a/web/api/queries/stddev/README.md b/web/api/queries/stddev/README.md
index 2fca47d5e..f0586a062 100644
--- a/web/api/queries/stddev/README.md
+++ b/web/api/queries/stddev/README.md
@@ -1,6 +1,10 @@
 <!--
 title: "standard deviation (`stddev`)"
+sidebar_label: "standard deviation (`stddev`)"
 custom_edit_url: https://github.com/netdata/netdata/edit/master/web/api/queries/stddev/README.md
+learn_status: "Published"
+learn_topic_type: "References"
+learn_rel_path: "Developers/Web/Api/Queries"
 -->
 
 # standard deviation (`stddev`)
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;
 
diff --git a/web/api/queries/stddev/stddev.h b/web/api/queries/stddev/stddev.h
index 4b8ffcd53..f7a1a06c3 100644
--- a/web/api/queries/stddev/stddev.h
+++ b/web/api/queries/stddev/stddev.h
@@ -6,13 +6,115 @@
 #include "../query.h"
 #include "../rrdr.h"
 
-void grouping_create_stddev(RRDR *r, const char *options __maybe_unused);
-void grouping_reset_stddev(RRDR *r);
-void grouping_free_stddev(RRDR *r);
-void grouping_add_stddev(RRDR *r, NETDATA_DOUBLE value);
-NETDATA_DOUBLE grouping_flush_stddev(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr);
-NETDATA_DOUBLE grouping_flush_coefficient_of_variation(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr);
-// NETDATA_DOUBLE grouping_flush_mean(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr);
-// NETDATA_DOUBLE grouping_flush_variance(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr);
+// this implementation comes from:
+// https://www.johndcook.com/blog/standard_deviation/
+
+struct tg_stddev {
+    long count;
+    NETDATA_DOUBLE m_oldM, m_newM, m_oldS, m_newS;
+};
+
+static inline void tg_stddev_create(RRDR *r, const char *options __maybe_unused) {
+    r->time_grouping.data = onewayalloc_callocz(r->internal.owa, 1, sizeof(struct tg_stddev));
+}
+
+// resets when switches dimensions
+// so, clear everything to restart
+static inline void tg_stddev_reset(RRDR *r) {
+    struct tg_stddev *g = (struct tg_stddev *)r->time_grouping.data;
+    g->count = 0;
+}
+
+static inline void tg_stddev_free(RRDR *r) {
+    onewayalloc_freez(r->internal.owa, r->time_grouping.data);
+    r->time_grouping.data = NULL;
+}
+
+static inline void tg_stddev_add(RRDR *r, NETDATA_DOUBLE value) {
+    struct tg_stddev *g = (struct tg_stddev *)r->time_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 tg_stddev_mean(struct tg_stddev *g) {
+    return (g->count > 0) ? g->m_newM : 0.0;
+}
+
+static inline NETDATA_DOUBLE tg_stddev_variance(struct tg_stddev *g) {
+    return ( (g->count > 1) ? g->m_newS/(NETDATA_DOUBLE)(g->count - 1) : 0.0 );
+}
+static inline NETDATA_DOUBLE tg_stddev_stddev(struct tg_stddev *g) {
+    return sqrtndd(tg_stddev_variance(g));
+}
+
+static inline NETDATA_DOUBLE tg_stddev_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) {
+    struct tg_stddev *g = (struct tg_stddev *)r->time_grouping.data;
+
+    NETDATA_DOUBLE value;
+
+    if(likely(g->count > 1)) {
+        value = tg_stddev_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;
+    }
+
+    tg_stddev_reset(r);
+
+    return  value;
+}
+
+// https://en.wikipedia.org/wiki/Coefficient_of_variation
+static inline NETDATA_DOUBLE tg_stddev_coefficient_of_variation_flush(RRDR *r, RRDR_VALUE_FLAGS *rrdr_value_options_ptr) {
+    struct tg_stddev *g = (struct tg_stddev *)r->time_grouping.data;
+
+    NETDATA_DOUBLE value;
+
+    if(likely(g->count > 1)) {
+        NETDATA_DOUBLE m = tg_stddev_mean(g);
+        value = 100.0 * tg_stddev_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;
+    }
+
+    tg_stddev_reset(r);
+
+    return  value;
+}
 
 #endif //NETDATA_API_QUERIES_STDDEV_H