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Task/Averages-Mean-angle/Phix/averages-mean-angle.phix

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+function atan2(atom y, atom x)
+    return 2*arctan((sqrt(power(x,2)+power(y,2))-x)/y)
+end function
+
+function MeanAngle(sequence angles)
+atom x=0, y=0, ai_rad
+integer l=length(angles)
+
+    for i=1 to l do
+        ai_rad = angles[i]*PI/180
+        x += cos(ai_rad)
+        y += sin(ai_rad)
+    end for
+    if abs(x)<1e-16 then return "not meaningful" end if
+    return sprintf("%9.5f",atan2(y,x)*180/PI)
+end function
+
+constant AngleLists = {{350,10},{90,180,270,360},{10,20,30},{180},{0,180}}
+sequence ai
+for i=1 to length(AngleLists) do
+    ai = AngleLists[i]
+    printf(1,"%+16s: Mean Angle is %s\n",{sprint(ai),MeanAngle(ai)})
+end for
+{} = wait_key()