From 9b796531b2ddb3b2bc1de58003e406f2022b0790 Mon Sep 17 00:00:00 2001
From: cschwinne <dev.aircoookie@gmail.com>
Date: Sun, 23 May 2021 18:49:23 +0200
Subject: [PATCH] Fixed Sunrise calculation (atan_t approx. used outside of
 value range)

---
 CHANGELOG.md       |  5 +++
 wled00/mqtt.cpp    |  2 +-
 wled00/wled_math.h | 81 ++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 74 insertions(+), 14 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 56c722e2..a989eaf3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 ### Builds after release 0.12.0
 
+#### Build 2105230
+
+-   No longer retain MQTT `/v` topic to alleviate storage loads on MQTT broker
+-   Fixed Sunrise calculation (atan_t approx. used outside of value range)
+
 #### Build 2105200
 
 -   Fixed WS281x output on ESP32
diff --git a/wled00/mqtt.cpp b/wled00/mqtt.cpp
index 79de0afb..8540335b 100644
--- a/wled00/mqtt.cpp
+++ b/wled00/mqtt.cpp
@@ -137,7 +137,7 @@ void publishMqtt()
   XML_response(nullptr, apires);
   strcpy(subuf, mqttDeviceTopic);
   strcat_P(subuf, PSTR("/v"));
-  mqtt->publish(subuf, 0, true, apires);
+  mqtt->publish(subuf, 0, false, apires);
 }
 
 
diff --git a/wled00/wled_math.h b/wled00/wled_math.h
index 88d24179..8629ea09 100644
--- a/wled00/wled_math.h
+++ b/wled00/wled_math.h
@@ -11,6 +11,8 @@
 
 #include <Arduino.h> //PI constant
 
+//#define WLED_DEBUG_MATH
+
 #define modd(x, y) ((x) - (int)((x) / (y)) * (y))
 
 float cos_t(float x)
@@ -24,38 +26,58 @@ float cos_t(float x)
   }
   float xx = x * x;
 
-  return sign * (1 - ((xx) / (2)) + ((xx * xx) / (24)) - ((xx * xx * xx) / (720)) + ((xx * xx * xx * xx) / (40320)) - ((xx * xx * xx * xx * xx) / (3628800)) + ((xx * xx * xx * xx * xx * xx) / (479001600)));
+  float res = sign * (1 - ((xx) / (2)) + ((xx * xx) / (24)) - ((xx * xx * xx) / (720)) + ((xx * xx * xx * xx) / (40320)) - ((xx * xx * xx * xx * xx) / (3628800)) + ((xx * xx * xx * xx * xx * xx) / (479001600)));
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("cos: %f,%f\n",res,cos(x));
+  #endif
+  return res;
 }
 
 float sin_t(float x) {
-  return cos_t(HALF_PI - x);
+  float res =  cos_t(HALF_PI - x);
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("sin: %f,%f\n",res,sin(x));
+  #endif
+  return res;
 }
 
 float tan_t(float x) {
   float c = cos_t(x);
   if (c==0.0) return 0;
-  return sin_t(x) / c;
+  float res = sin_t(x) / c;
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("tan: %f,%f\n",res,tan(x));
+  #endif
+  return res;
 }
 
 //https://stackoverflow.com/questions/3380628
 // Absolute error <= 6.7e-5
 float acos_t(float x) {
   float negate = float(x < 0);
-  x = std::abs(x);
+  float xabs = std::abs(x);
   float ret = -0.0187293;
-  ret = ret * x;
+  ret = ret * xabs;
   ret = ret + 0.0742610;
-  ret = ret * x;
+  ret = ret * xabs;
   ret = ret - 0.2121144;
-  ret = ret * x;
+  ret = ret * xabs;
   ret = ret + HALF_PI;
-  ret = ret * sqrt(1.0-x);
+  ret = ret * sqrt(1.0-xabs);
   ret = ret - 2 * negate * ret;
-  return negate * PI + ret;
+  float res = negate * PI + ret;
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("acos,%f,%f,%f\n",x,res,acos(x));
+  #endif
+  return res;
 }
 
 float asin_t(float x) {
-  return HALF_PI - acos_t(x);
+  float res = HALF_PI - acos_t(x);
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("asin,%f,%f,%f\n",x,res,asin(x));
+  #endif
+  return res;
 }
 
 //https://stackoverflow.com/a/42542593
@@ -63,21 +85,54 @@ float asin_t(float x) {
 #define B -0.287434475393028
 #define C ((HALF_PI/2) - A - B)
 
+//polynominal factors for approximation between 1 and 5
+#define C0 0.089494f
+#define C1 0.974207f
+#define C2 -0.326175f
+#define C3 0.05375f
+#define C4 -0.003445f
+
 float atan_t(float x) {
-  float xx = x * x;
-  return ((A*xx + B)*xx + C)*x;
+  bool neg = (x < 0);
+  #ifdef WLED_DEBUG_MATH
+  float xinput = x;
+  #endif
+  x = std::abs(x);
+  float res;
+  if (x > 5.0f) { //atan(x) converges to pi/2 - (1/x) for large values
+    res = HALF_PI - (1.0f/x);
+  }
+  else if (x > 1.0f) { //1 < x < 5
+    float xx = x * x;
+    res = (C4*xx*xx)+(C3*xx*x)+(C2*xx)+(C1*x)+C0;
+  } else { //this approximation is only for x <= 1
+    float xx = x * x;
+    res = ((A*xx + B)*xx + C)*x;
+  }
+  if (neg) res = -res;
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("atan,%f,%f,%f\n",xinput,res,atan(xinput));
+  #endif
+  return res;
 }
 
 float floor_t(float x) {
   bool neg = x < 0;
   int val = x;
   if (neg) val--;
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("floor: %f,%f\n",val,floor(x));
+  #endif
   return val;
 }
 
 float fmod_t(float num, float denom) {
   int tquot = num / denom;
-  return num - tquot * denom;
+  float res = num - tquot * denom;
+  #ifdef WLED_DEBUG_MATH
+  Serial.printf("fmod: %f,%f\n",res,fmod(num,denom));
+  #endif
+  return res;
 }
 
 #endif
\ No newline at end of file