[SciPy-user] Finding local minima of greater than a given depth

Zane Selvans zane@ideotrope....
Thu Aug 14 14:40:18 CDT 2008


Is there a function within scipy somewhere which will, given an array  
representing values of a function, find all the local minima having a  
depth greater than some specified minimum?  The following works great  
for smooth functions, but when the data has noise in it, it also  
returns all of the (very) local minima, which I don't want.  The  
functions I'm working with are periodic (hence the modulo in the  
indices for endpoint cases).  Or, if there isn't such a built in  
functionality, what's the right way to measure the depth of a local  
minimum?

def local_minima(fitlist):
     minima = []

     for i in range(len(fitlist)):
         if fitlist[i] < fitlist[mod(i+1,len(fitlist))] and fitlist[i]  
< fitlist[mod(i-1,len(fitlist))]:
             minima.append(fitlist[i])

     minima.sort()

     good_indices = [ fitlist.index(fit) for fit in minima ]
     good_fits = [ fit for fit in minima ]

     return(good_indices, good_fits)

--
Zane Selvans
Amateur Earthling
http://zaneselvans.org
zane@ideotrope.org
303/815-6866
PGP Key: 55E0815F



More information about the SciPy-user mailing list