examples: add realtime result demo

examples/flopping_f_simulation.py

@@ -0,0 +1,45 @@
+from math import sqrt, cos, pi
+import time
+
+from artiq import *
+
+
+def model(x, F0=1500, A=80, B=40, t=0.02, tpi=0.03):
+    return A+(B-A)/2/(4*tpi**2*(x-F0)**2+1)*(1-cos(pi*t/tpi*sqrt(4*tpi**2*(x-F0)**2+1)))
+
+
+class FloppingF(AutoDB):
+    class DBKeys:
+        implicit_core = False
+
+        npoints = Argument(100)
+        min_freq = Argument(1000)
+        max_freq = Argument(2000)
+
+        frequency = Result()
+        brightness = Result()
+
+        flopping_freq = Parameter()
+
+    @staticmethod
+    def realtime_results():
+        return {
+            ("frequency", "brightness"): "xy"
+        }
+
+    def run(self):
+        for i in range(self.npoints):
+            frequency = (self.max_freq-self.min_freq)*i/(self.npoints - 1) + self.min_freq
+            brightness = model(frequency)
+            self.frequency.append(frequency)
+            self.brightness.append(brightness)
+            time.sleep(0.1)
+        self.analyze()
+
+    def analyze(self):
+        min_f = self.frequency.read[0]
+        min_b = self.brightness.read[0]
+        for f, b in zip(self.frequency.read, self.brightness.read):
+            if b < min_b:
+                min_f, min_b = f, b
+        self.flopping_freq = min_f