added efficiency metric

rowers/dataprep.py

@@ -210,6 +210,12 @@ def clean_df_stats(datadf,workstrokesonly=True,ignorehr=True,
         datadf.loc[mask,'pace'] = np.nan
     except KeyError:
         pass
+
+    try:
+        mask = datadf['efficiency'] < 0.
+        datadf.loc[mask,'efficiency'] = np.nan
+    except KeyError:
+        pass
         
     try:
         mask = datadf['pace']/1000. < 60.
@@ -1423,6 +1429,14 @@ def dataprep(rowdatadf,id=0,bands=True,barchart=True,otwpower=True,
             totalangle = savgol_filter(totalangle,windowsize,3)
             effectiveangle = savgol_filter(effectiveangle,windowsize,3)
 
+        velo = 500./p
+
+        ergpw = 2.8*velo**3
+        efficiency = 100.*ergpw/power
+
+        efficiency = efficiency.replace([-np.inf,np.inf],np.nan)
+        efficiency.fillna(method='ffill')
+            
         data['wash'] = wash
         data['catch'] = catch
         data['slip'] = slip
@@ -1432,6 +1446,7 @@ def dataprep(rowdatadf,id=0,bands=True,barchart=True,otwpower=True,
         data['drivelength'] = drivelength
         data['totalangle'] = totalangle
         data['effectiveangle'] = effectiveangle
+        data['efficiency'] = efficiency
         
     if otwpower:
 	try: