adding example to plot activation for single neuron

plotting.py

@@ -233,3 +233,17 @@ if __name__ == "__main__":
                           var2_index=c.branches.index("mt"), var2_range=(0, 500, 10),
                           var1_label="met [GeV]", var2_label="mt [GeV]")
 
+    import keras.backend as K
+    # single neuron
+    def eval_single_neuron(x):
+        layer = 3
+        neuron = 0
+        x_eval = c.scaler.transform(x)
+        f = K.function([c.model.input]+[K.learning_phase()], [c.model.layers[layer].output])
+        return f([x_eval])[0][:,neuron]
+
+    plot_NN_vs_var_2D("mt_vs_met_crosscheck.pdf", means=mean_signal,
+                      scorefun=eval_single_neuron,
+                      var1_index=c.branches.index("met"), var1_range=(0, 1000, 10),
+                      var2_index=c.branches.index("mt"), var2_range=(0, 500, 10),
+                      var1_label="met [GeV]", var2_label="mt [GeV]")