new function getResolutionWindow and doc testing added

pylot/core/pick/utils.py

@@ -398,6 +398,43 @@ def getsignalwin(t, t1, tsignal):
     return isignal
 
 
+def getResolutionWindow(snr):
+    """
+    Number -> Float
+    produce the half of the time resolution window width from given SNR
+    value
+          SNR >= 3    ->  2 sec    HRW
+      3 > SNR >= 2    ->  5 sec    MRW
+      2 > SNR >= 1.5  -> 10 sec    LRW
+    1.5 > SNR         -> 15 sec   VLRW
+    see also Diehl et al. 2009
+
+    >>> getResolutionWindow(0.5)
+    7.5
+    >>> getResolutionWindow(1.8)
+    5.0
+    >>> getResolutionWindow(2.3)
+    2.5
+    >>> getResolutionWindow(4)
+    1.0
+    >>> getResolutionWindow(2)
+    2.5
+    """
+
+    res_wins = {'HRW': 2., 'MRW': 5., 'LRW': 10., 'VLRW': 15.}
+
+    if snr < 1.5:
+        time_resolution = res_wins['VLRW']
+    elif snr < 2.:
+        time_resolution = res_wins['LRW']
+    elif snr < 3.:
+        time_resolution = res_wins['MRW']
+    else:
+        time_resolution = res_wins['HRW']
+
+    return time_resolution/2
+
+
 def wadaticheck(pickdic, dttolerance, iplot):
     '''
     Function to calculate Wadati-diagram from given P and S onsets in order
@@ -596,4 +633,6 @@ def checksignallength(X, pick, TSNR, minsiglength, nfac, minpercent, iplot):
 
     return returnflag
 
-
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()