A-M baby

Task/Averages-Simple-moving-average/GAP/averages-simple-moving-average.gap

@@ -0,0 +1,27 @@
+MovingAverage := function(n)
+  local sma, buffer, pos, sum, len;
+  buffer := List([1 .. n], i -> 0);
+  pos := 0;
+  len := 0;
+  sum := 0;
+  sma := function(x)
+    pos := RemInt(pos, n) + 1;
+    sum := sum + x - buffer[pos];
+    buffer[pos] := x;
+    len := Minimum(len + 1, n);
+    return sum/len;
+  end;
+  return sma;
+end;
+
+f := MovingAverage(3);
+f(1);  #  1
+f(2);  #  3/2
+f(3);  #  2
+f(4);  #  3
+f(5);  #  4
+f(5);  #  14/3
+f(4);  #  14/3
+f(3);  #  4
+f(2);  #  3
+f(1);  #  2