From edd3e3c34a5093e550eb326c4ee6bd339726ef5f Mon Sep 17 00:00:00 2001
From: Lucas De Marchi <lucas.demarchi@intel.com>
Date: Thu, 18 Feb 2016 02:28:52 -0200
Subject: [PATCH] Filter: silence warning about unused function
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

../../libraries/Filter/examples/Derivative/Derivative.cpp:16:14: warning: ‘float noise()’ defined but not used [-Wunused-function]
 static float noise(void)
              ^
---
 libraries/Filter/examples/Derivative/Derivative.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libraries/Filter/examples/Derivative/Derivative.cpp b/libraries/Filter/examples/Derivative/Derivative.cpp
index 962e9fc222..20de02e97e 100644
--- a/libraries/Filter/examples/Derivative/Derivative.cpp
+++ b/libraries/Filter/examples/Derivative/Derivative.cpp
@@ -8,6 +8,8 @@
 
 const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
+#define USE_NOISE 0
+
 DerivativeFilter<float,11> derivative;
 
 // setup routine
@@ -15,7 +17,11 @@ void setup(){}
 
 static float noise(void)
 {
+#if USE_NOISE
     return ((random() % 100)-50) * 0.001f;
+#else
+    return 0;
+#endif
 }
 
 //Main loop where the action takes place
@@ -24,7 +30,7 @@ void loop()
     hal.scheduler->delay(50);
     float t = AP_HAL::millis()*1.0e-3f;
     float s = sinf(t);
-    //s += noise();
+    s += noise();
     uint32_t t1 = AP_HAL::micros();
     derivative.update(s, t1);
     float output = derivative.slope() * 1.0e6f;