Move 'blind window' and 'min peaks' from FlatPeaksCommand to FlatFiltPlugin
[hooke.git] / hooke / plugin / fit.py
old mode 100755 (executable)
new mode 100644 (file)
index b883ef1..1718c1a
@@ -1,21 +1,39 @@
-#!/usr/bin/env python
+# Copyright (C) 2008-2010 Alberto Gomez-Casado
+#                         Fabrizio Benedetti
+#                         Massimo Sandal <devicerandom@gmail.com>
+#                         W. Trevor King <wking@drexel.edu>
+#
+# This file is part of Hooke.
+#
+# Hooke is free software: you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation, either
+# version 3 of the License, or (at your option) any later version.
+#
+# Hooke is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with Hooke.  If not, see
+# <http://www.gnu.org/licenses/>.
 
-'''
-FIT
-
-Force spectroscopy curves basic fitting plugin.
-Licensed under the GNU GPL version 2
+"""Force spectroscopy curves basic fitting plugin.
 
 Non-standard Dependencies:
 procplots.py (plot processing plugin)
-'''
-from libhooke import WX_GOOD, ClickedPoint
+"""
+
+from ..libhooke import WX_GOOD, ClickedPoint
+
 import wxversion
 wxversion.select(WX_GOOD)
 #from wx import PostEvent
 #from wx.lib.newevent import NewEvent
 import scipy
 import scipy.odr
+import scipy.stats
 import numpy as np
 import copy
 import Queue
@@ -29,12 +47,19 @@ global events_from_fit
 events_from_fit=Queue.Queue() #GUI ---> CLI COMMUNICATION
 
 
-class fitCommands:
-    
+class fitCommands(object):
+
     def _plug_init(self):
         self.wlccurrent=None
         self.wlccontact_point=None
         self.wlccontact_index=None
+        
+    def dist2fit(self):
+        '''Calculates the average distance from data to fit, scaled by the standard deviation
+        of the free cantilever area (thermal noise)
+        '''
+                
+        
     
     def wlc_fit(self,clicked_points,xvector,yvector, pl_value, T=293, return_errors=False):
         '''
@@ -42,52 +67,54 @@ class fitCommands:
         The function is the simple polynomial worm-like chain as proposed by C.Bustamante, J.F.Marko, E.D.Siggia
         and S.Smith (Science. 1994 Sep 9;265(5178):1599-600.)
         '''
-    
+
         '''
         clicked_points[0] = contact point (calculated or hand-clicked)
         clicked_points[1] and [2] are edges of chunk
         '''
-    
+
         #STEP 1: Prepare the vectors to apply the fit.
-        
-        
         if pl_value is not None:
             pl_value=pl_value/(10**9)
-        
+
         #indexes of the selected chunk
         first_index=min(clicked_points[1].index, clicked_points[2].index)
         last_index=max(clicked_points[1].index, clicked_points[2].index)
-               
+
         #getting the chunk and reverting it
         xchunk,ychunk=xvector[first_index:last_index],yvector[first_index:last_index]
         xchunk.reverse()
-        ychunk.reverse()    
+        ychunk.reverse()
         #put contact point at zero and flip around the contact point (the fit wants a positive growth for extension and force)
         xchunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xchunk]
         ychunk_corr_up=[-(y-clicked_points[0].graph_coords[1]) for y in ychunk]
-        
+
         #make them arrays
         xchunk_corr_up=scipy.array(xchunk_corr_up)
         ychunk_corr_up=scipy.array(ychunk_corr_up)
-    
-        
+
+
         #STEP 2: actually do the fit
-    
+
         #Find furthest point of chunk and add it a bit; the fit must converge
         #from an excess!
         xchunk_high=max(xchunk_corr_up)
         xchunk_high+=(xchunk_high/10)
-    
+
         #Here are the linearized start parameters for the WLC.
         #[lambd=1/Lo , pii=1/P]
-    
+
         p0=[(1/xchunk_high),(1/(3.5e-10))]
         p0_plfix=[(1/xchunk_high)]
         '''
         ODR STUFF
         fixme: remove these comments after testing
         '''
-        
+        def dist(px,py,linex,liney):
+            distancesx=scipy.array([(px-x)**2 for x in linex])
+            minindex=np.argmin(distancesx)
+            print px, linex[0], linex[-1]
+            return (py-liney[minindex])**2
         
         def f_wlc(params,x,T=T):
             '''
@@ -98,7 +125,7 @@ class fitCommands:
             therm=Kb*T
             y=(therm*pii/4.0) * (((1-(x*lambd))**-2) - 1 + (4*x*lambd))
             return y
-        
+
         def f_wlc_plfix(params,x,pl_value=pl_value,T=T):
             '''
             wlc function for ODR fitting
@@ -109,7 +136,7 @@ class fitCommands:
             therm=Kb*T
             y=(therm*pii/4.0) * (((1-(x*lambd))**-2) - 1 + (4*x*lambd))
             return y
-        
+
         #make the ODR fit
         realdata=scipy.odr.RealData(xchunk_corr_up,ychunk_corr_up)
         if pl_value:
@@ -118,11 +145,11 @@ class fitCommands:
         else:
             model=scipy.odr.Model(f_wlc)
             o = scipy.odr.ODR(realdata, model, p0)
-        
+
         o.set_job(fit_type=2)
         out=o.run()
         fit_out=[(1/i) for i in out.beta]
-        
+
         #Calculate fit errors from output standard deviations.
         #We must propagate the error because we fit the *inverse* parameters!
         #The error = (error of the inverse)*(value**2)
@@ -130,8 +157,8 @@ class fitCommands:
         for sd,value in zip(out.sd_beta, fit_out):
             err_real=sd*(value**2)
             fit_errors.append(err_real)
-        
-        def wlc_eval(x,params,pl_value,T):    
+
+        def wlc_eval(x,params,pl_value,T):
             '''
             Evaluates the WLC function
             '''
@@ -139,17 +166,18 @@ class fitCommands:
                 lambd, pii = params
             else:
                 lambd = params
-        
+
             if pl_value:
                 pii=1/pl_value
-        
+
             Kb=(1.38065e-23) #boltzmann constant
             therm=Kb*T #so we have thermal energy
-        
+
             return ( (therm*pii/4.0) * (((1-(x*lambd))**-2.0) - 1 + (4.0*x*lambd)) )
         
-        #STEP 3: plotting the fit
         
+        #STEP 3: plotting the fit
+
         #obtain domain to plot the fit - from contact point to last_index plus 20 points
         thule_index=last_index+10
         if thule_index > len(xvector): #for rare cases in which we fit something at the END of whole curve.
@@ -159,16 +187,26 @@ class fitCommands:
         xfit_chunk.reverse()
         xfit_chunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xfit_chunk]
         xfit_chunk_corr_up=scipy.array(xfit_chunk_corr_up)
-    
+
         #the fitted curve: reflip, re-uncorrect
         yfit=wlc_eval(xfit_chunk_corr_up, out.beta, pl_value,T)
         yfit_down=[-y for y in yfit]
         yfit_corr_down=[y+clicked_points[0].graph_coords[1] for y in yfit_down]
+        
+        
+        #calculate fit quality 
+        qsum=0
+        yqeval=wlc_eval(xchunk_corr_up,out.beta,pl_value,T)
+        #we need to cut the extra from thuleindex
+        for qindex in np.arange(0,len(yqeval)):
+            qsum+=(yqeval[qindex]-ychunk_corr_up[qindex])**2        
+        qstd=np.sqrt(qsum/len(ychunk_corr_up))        
+        
     
         if return_errors:
-            return fit_out, yfit_corr_down, xfit_chunk, fit_errors
+            return fit_out, yfit_corr_down, xfit_chunk, fit_errors, qstd
         else:
-            return fit_out, yfit_corr_down, xfit_chunk, None
+            return fit_out, yfit_corr_down, xfit_chunk, None, qstd
     
     def fjc_fit(self,clicked_points,xvector,yvector, pl_value, T=293, return_errors=False):
         '''
@@ -179,51 +217,57 @@ class fitCommands:
         clicked_points[0] is the contact point (calculated or hand-clicked)
         clicked_points[1] and [2] are edges of chunk
         '''
-        
+
         #STEP 1: Prepare the vectors to apply the fit.
         if pl_value is not None:
             pl_value=pl_value/(10**9)
-        
+
         #indexes of the selected chunk
         first_index=min(clicked_points[1].index, clicked_points[2].index)
         last_index=max(clicked_points[1].index, clicked_points[2].index)
-        
+
         #getting the chunk and reverting it
         xchunk,ychunk=xvector[first_index:last_index],yvector[first_index:last_index]
         xchunk.reverse()
-        ychunk.reverse()    
+        ychunk.reverse()
         #put contact point at zero and flip around the contact point (the fit wants a positive growth for extension and force)
         xchunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xchunk]
         ychunk_corr_up=[-(y-clicked_points[0].graph_coords[1]) for y in ychunk]
-        
-        
+
+
         #make them arrays
         xchunk_corr_up=scipy.array(xchunk_corr_up)
         ychunk_corr_up=scipy.array(ychunk_corr_up)
-    
-        
+
+
         #STEP 2: actually do the fit
-    
+
         #Find furthest point of chunk and add it a bit; the fit must converge
         #from an excess!
         xchunk_high=max(xchunk_corr_up)
         xchunk_high+=(xchunk_high/10)
-    
+
         #Here are the linearized start parameters for the WLC.
         #[lambd=1/Lo , pii=1/P]
-    
+
         p0=[(1/xchunk_high),(1/(3.5e-10))]
         p0_plfix=[(1/xchunk_high)]
         '''
         ODR STUFF
         fixme: remove these comments after testing
         '''
+        def dist(px,py,linex,liney):
+            distancesx=scipy.array([(px-x)**2 for x in linex])
+            minindex=np.argmin(distancesx)
+            print minindex, px, linex[0], linex[-1]
+            return (py-liney[minindex])**2
+        
         def coth(z):
             '''
             hyperbolic cotangent
             '''
             return (np.exp(2*z)+1)/(np.exp(2*z)-1)
-        
+
         def x_fjc(params,f,T=T):
             '''
             fjc function for ODR fitting
@@ -231,11 +275,11 @@ class fitCommands:
             lambd,pii=params
             Kb=(1.38065e-23)
             therm=Kb*T
-            
+
             #x=(therm*pii/4.0) * (((1-(x*lambd))**-2) - 1 + (4*x*lambd))
             x=(1/lambd)*(coth(f*(1/pii)/therm) - (therm*pii)/f)
             return x
-        
+
         def x_fjc_plfix(params,f,pl_value=pl_value,T=T):
             '''
             fjc function for ODR fitting
@@ -247,7 +291,7 @@ class fitCommands:
             #y=(therm*pii/4.0) * (((1-(x*lambd))**-2) - 1 + (4*x*lambd))
             x=(1/lambd)*(coth(f*(1/pii)/therm) - (therm*pii)/f)
             return x
-        
+
         #make the ODR fit
         realdata=scipy.odr.RealData(ychunk_corr_up,xchunk_corr_up)
         if pl_value:
@@ -256,11 +300,11 @@ class fitCommands:
         else:
             model=scipy.odr.Model(x_fjc)
             o = scipy.odr.ODR(realdata, model, p0)
-        
+
         o.set_job(fit_type=2)
         out=o.run()
         fit_out=[(1/i) for i in out.beta]
-        
+
         #Calculate fit errors from output standard deviations.
         #We must propagate the error because we fit the *inverse* parameters!
         #The error = (error of the inverse)*(value**2)
@@ -268,8 +312,8 @@ class fitCommands:
         for sd,value in zip(out.sd_beta, fit_out):
             err_real=sd*(value**2)
             fit_errors.append(err_real)
-        
-        def fjc_eval(y,params,pl_value,T):    
+
+        def fjc_eval(y,params,pl_value,T):
             '''
             Evaluates the WLC function
             '''
@@ -277,16 +321,235 @@ class fitCommands:
                 lambd, pii = params
             else:
                 lambd = params
-        
+
             if pl_value:
                 pii=1/pl_value
-        
+
             Kb=(1.38065e-23) #boltzmann constant
             therm=Kb*T #so we have thermal energy
             #return ( (therm*pii/4.0) * (((1-(x*lambd))**-2.0) - 1 + (4.0*x*lambd)) )
             return (1/lambd)*(coth(y*(1/pii)/therm) - (therm*pii)/y)
+
+
+
+        #STEP 3: plotting the fit
+        #obtain domain to plot the fit - from contact point to last_index plus 20 points
+        thule_index=last_index+10
+        if thule_index > len(xvector): #for rare cases in which we fit something at the END of whole curve.
+            thule_index = len(xvector)
+        #reverse etc. the domain
+        ychunk=yvector[clicked_points[0].index:thule_index]
+
+        if len(ychunk)>0:
+            y_evalchunk=np.linspace(min(ychunk),max(ychunk),100)
+        else:
+            #Empty y-chunk. It happens whenever we set the contact point after a recognized peak,
+            #or other buggy situations. Kludge to live with it now...
+            ychunk=yvector[:thule_index]
+            y_evalchunk=np.linspace(min(ychunk),max(ychunk),100)
+
+        yfit_down=[-y for y in y_evalchunk]
+        yfit_corr_down=[y+clicked_points[0].graph_coords[1] for y in yfit_down]
+        yfit_corr_down=scipy.array(yfit_corr_down)
+
+        #the fitted curve: reflip, re-uncorrect
+        xfit=fjc_eval(yfit_corr_down, out.beta, pl_value,T)
+        xfit=list(xfit)
+        xfit.reverse()
+        xfit_chunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xfit]
+
+        #xfit_chunk_corr_up=scipy.array(xfit_chunk_corr_up)
+        #deltay=yfit_down[0]-yvector[clicked_points[0].index]
+
+        #This is a terrible, terrible kludge to find the point where it should normalize (and from where it should plot)
+        xxxdists=[]
+        for index in scipy.arange(1,len(xfit_chunk_corr_up),1):
+            xxxdists.append((clicked_points[0].graph_coords[0]-xfit_chunk_corr_up[index])**2)
+        normalize_index=xxxdists.index(min(xxxdists))
+        #End of kludge
+
+        deltay=yfit_down[normalize_index]-clicked_points[0].graph_coords[1]
+        yfit_corr_down=[y-deltay for y in yfit_down]
+        
+        
+        #calculate fit quality
+        #creates dense y vector
+        yqeval=np.linspace(np.min(ychunk_corr_up)/2,np.max(ychunk_corr_up)*2,10*len(ychunk_corr_up))
+        #corresponding fitted x
+        xqeval=fjc_eval(yqeval,out.beta,pl_value,T)
+        
+        qsum=0
+        for qindex in np.arange(0,len(ychunk_corr_up)):
+            qsum+=dist(xchunk_corr_up[qindex],ychunk_corr_up[qindex],xqeval,yqeval)        
+        qstd=np.sqrt(qsum/len(ychunk_corr_up))        
+        
+            
+        if return_errors:
+            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], fit_errors, qstd
+        else:
+            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], None, qstd
+    
+    def efjc_fit(self,clicked_points,xvector,yvector, pl_value, T=293.0, return_errors=False):
+        '''
+        Extended Freely-jointed chain function
+        ref: F Oesterhelt, M Rief and H E Gaub, New Journal of Physics 1 (1999) 6.1–6.11 
+        Please note that 2-parameter fitting (length and kl) usually does not converge, use fixed kl
+        '''
+        '''
+        clicked_points[0] is the contact point (calculated or hand-clicked)
+        clicked_points[1] and [2] are edges of chunk
+        
+        '''
+        #Fixed parameters from reference
+        Kb=(1.38065e-2) #in pN.nm
+        Lp=0.358 #planar, nm
+        Lh=0.280 #helical, nm
+        Ks=150e3  #pN/nm
+        
+       
+        #STEP 1: Prepare the vectors to apply the fit.
+        
+        #indexes of the selected chunk
+        first_index=min(clicked_points[1].index, clicked_points[2].index)
+        last_index=max(clicked_points[1].index, clicked_points[2].index)
+        
+        #getting the chunk and reverting it
+        xchunk,ychunk=xvector[first_index:last_index],yvector[first_index:last_index]
+        xchunk.reverse()
+        ychunk.reverse()    
+        #put contact point at zero and flip around the contact point (the fit wants a positive growth for extension and force)
+        xchunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xchunk]
+        ychunk_corr_up=[-(y-clicked_points[0].graph_coords[1]) for y in ychunk]
+        
+        
+        #make them arrays
+        xchunk_corr_up=scipy.array(xchunk_corr_up)
+        ychunk_corr_up=scipy.array(ychunk_corr_up)
+        
+        xchunk_corr_up_nm=xchunk_corr_up*1e9
+        ychunk_corr_up_pn=ychunk_corr_up*1e12
+    
+        
+        #STEP 2: actually do the fit
+    
+        #Find furthest point of chunk and add it a bit; the fit must converge
+        #from an excess!
+        xchunk_high=max(xchunk_corr_up_nm)
+        xchunk_high+=(xchunk_high/10.0)
+    
+        #Here are the linearized start parameters for the WLC.
+        #[Ns , pii=1/P]
+        #max number of monomers (all helical)for a contour length xchunk_high
+        excessNs=xchunk_high/(Lp) 
+        p0=[excessNs,(1.0/(0.7))]
+        p0_plfix=[(excessNs)]
+    
+        def dist(px,py,linex,liney):
+            distancesx=scipy.array([(px-x)**2 for x in linex])
+            minindex=np.argmin(distancesx)
+            return (py-liney[minindex])**2
+    
+        def deltaG(f):
+            dG0=12.4242 #3kt in pN.nm
+            dL=0.078 #planar-helical
+            return dG0-f*dL
+        
+        def Lfactor(f,T=T):
+            Lp=0.358 #planar, nm
+            Lh=0.280 #helical, nm
+            Kb=(1.38065e-2)
+            therm=Kb*T
+            dG=deltaG(f)
+            
+            return Lp/(np.exp(dG/therm)+1)+Lh/(np.exp(-dG/therm)+1)
+        
+        def coth(z):
+            '''
+            hyperbolic cotangent
+            '''
+            return 1.0/np.tanh(z)
+        
+        def x_efjc(params,f,T=T,Ks=Ks):
+            '''
+            efjc function for ODR fitting
+            '''
+            
+            Ns=params[0]
+            invkl=params[1]
+            Kb=(1.38065e-2)
+            therm=Kb*T            
+            beta=(f/therm)/invkl
+                        
+            x=Ns*Lfactor(f)*(coth(beta)-1.0/beta)+Ns*f/Ks
+            return x
+        
+        def x_efjc_plfix(params,f,kl_value=pl_value,T=T,Ks=Ks):
+            '''
+            efjc function for ODR fitting
+            '''
+            
+            Ns=params
+            invkl=1.0/kl_value
+            Kb=(1.38065e-2)
+            therm=Kb*T
+            beta=(f/therm)/invkl
+            
+            x=Ns*Lfactor(f)*(coth(beta)-1.0/beta)+Ns*f/Ks
+            return x
+        
+        #make the ODR fit
+        realdata=scipy.odr.RealData(ychunk_corr_up_pn,xchunk_corr_up_nm)
+        if pl_value:
+            model=scipy.odr.Model(x_efjc_plfix)
+            o = scipy.odr.ODR(realdata, model, p0_plfix)
+        else:
+            print 'WARNING eFJC fit with free pl sometimes does not converge'
+            model=scipy.odr.Model(x_efjc)
+            o = scipy.odr.ODR(realdata, model, p0)
+        
+        o.set_job(fit_type=2)
+        out=o.run()
+    
+        
+        Ns=out.beta[0]
+        Lc=Ns*Lp*1e-9 
+        if len(out.beta)>1:
+            kfit=1e-9/out.beta[1]
+            kfitnm=1/out.beta[1]
+        else:
+            kfit=1e-9*pl_value
+            kfitnm=pl_value
+        
+        fit_out=[Lc, kfit]
+        
+        #Calculate fit errors from output standard deviations.
+        fit_errors=[]
+        fit_errors.append(out.sd_beta[0]*Lp*1e-9)
+        if len(out.beta)>1:
+            fit_errors.append(1e9*out.sd_beta[1]*kfit**2)
             
+  
+        
+        def efjc_eval(y,params,pl_value,T=T,Lfactor=Lfactor,Ks=Ks):    
+            '''
+            Evaluates the eFJC function
+            '''
+            if not pl_value:
+                Ns, invkl = params
+            else:
+                Ns = params
         
+            if pl_value:
+                invkl=1.0/pl_value
+        
+            Kb=(1.38065e-2) #boltzmann constant
+            therm=Kb*T #so we have thermal energy
+            beta=(y/therm)/invkl
+
+            x= Ns*Lfactor(y)*(coth(beta)-1.0/beta)+Ns*y/Ks
+            
+            return x
+            
         #STEP 3: plotting the fit
         #obtain domain to plot the fit - from contact point to last_index plus 20 points
         thule_index=last_index+10
@@ -308,7 +571,7 @@ class fitCommands:
         yfit_corr_down=scipy.array(yfit_corr_down)
         
         #the fitted curve: reflip, re-uncorrect
-        xfit=fjc_eval(yfit_corr_down, out.beta, pl_value,T)
+        xfit=efjc_eval(1e12*yfit_corr_down, out.beta, pl_value,T)*1e-9
         xfit=list(xfit)
         xfit.reverse()
         xfit_chunk_corr_up=[-(x-clicked_points[0].graph_coords[0]) for x in xfit]
@@ -325,31 +588,44 @@ class fitCommands:
         
         deltay=yfit_down[normalize_index]-clicked_points[0].graph_coords[1]
         yfit_corr_down=[y-deltay for y in yfit_down]
+        
+        #calculate fit quality
+        #creates dense y vector
+        yqeval=np.linspace(np.min(ychunk_corr_up_pn)/2,np.max(ychunk_corr_up_pn)*2,10*len(ychunk_corr_up_pn))
+        #corresponding fitted x
+        xqeval=efjc_eval(yqeval,out.beta,pl_value)
+        
+        qsum=0
+        for qindex in np.arange(0,len(ychunk_corr_up_pn)):
+            qsum+=dist(xchunk_corr_up_nm[qindex],ychunk_corr_up_pn[qindex],xqeval,yqeval)        
+        qstd=1e-12*np.sqrt(qsum/len(ychunk_corr_up_pn))
             
         if return_errors:
-            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], fit_errors
+            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], fit_errors, qstd
         else:
-            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], None
+            return fit_out, yfit_corr_down[normalize_index+1:], xfit_chunk_corr_up[normalize_index+1:], None, qstd
+            
     
+   
     
     def do_wlc(self,args):
         '''
         WLC
         (fit.py plugin)
-        
+
         See the fit command
         '''
         self.do_fit(args)
-    
+
     def do_fjc(self,args):
         '''
         FJC
         (fit.py plugin)
-        
+
         See the fit command
         '''
         self.do_fit(args)
-    
+
     def do_fit(self,args):
         '''
         FIT
@@ -359,31 +635,37 @@ class fitCommands:
         First you have to click a contact point.
         Then you have to click the two edges of the data you want to fit.
         
+        Fit quality compares the distance to the fit with the thermal noise (a good fit should be close to 1)
+        
         The fit function depends on the fit_function variable. You can set it with the command
         "set fit_function wlc" or  "set fit_function fjc" depending on the function you prefer.
-        
-        For WLC, the function is the simple polynomial worm-like chain as proposed by 
-        C.Bustamante, J.F.Marko, E.D.Siggia and S.Smith (Science. 1994 
+
+        For WLC, the function is the simple polynomial worm-like chain as proposed by
+        C.Bustamante, J.F.Marko, E.D.Siggia and S.Smith (Science. 1994
         Sep 9;265(5178):1599-600.)
-        
-        For FJC, ref: 
+
+        For FJC, ref:
         C.Ray and B.B. Akhremitchev; http://www.chem.duke.edu/~boris/research/force_spectroscopy/fit_efjc.pdf
+        
+        For eFJC, ref:
+        F Oesterhelt, M Rief and H E Gaub, New Journal of Physics 1 (1999) 6.1–6.11 (section 4.2)
+        NOTE: use fixed pl for better results.
 
         Arguments:
-        pl=[value] : Use a fixed persistent length (WLC) or Kuhn length (FJC) for the fit. If pl is not given, 
-                     the fit will be a 2-variable  
+        pl=[value] : Use a fixed persistent length (WLC) or Kuhn length (FJC) for the fit. If pl is not given,
+                     the fit will be a 2-variable
                      fit. DO NOT put spaces between 'pl', '=' and the value.
-                     The value must be in nanometers. 
-        
+                     The value must be in nanometers.
+
         t=[value] : Use a user-defined temperature. The value must be in
                     kelvins; by default it is 293 K.
                     DO NOT put spaces between 't', '=' and the value.
-        
-        noauto : allows for clicking the contact point by 
+
+        noauto : allows for clicking the contact point by
                  hand (otherwise it is automatically estimated) the first time.
                  If subsequent measurements are made, the same contact point
                  clicked is used
-        
+
         reclick : redefines by hand the contact point, if noauto has been used before
                   but the user is unsatisfied of the previously choosen contact point.
         ---------
@@ -400,10 +682,10 @@ class fitCommands:
             if ('t=' in arg[0:2]) or ('T=' in arg[0:2]):
                 t_expression=arg.split('=')
                 T=float(t_expression[1])
-        
+
         #use the currently displayed plot for the fit
         displayed_plot=self._get_displayed_plot()
-               
+
         #handle contact point arguments correctly
         if 'reclick' in args.split():
             print 'Click contact point'
@@ -429,26 +711,30 @@ class fitCommands:
             contact_point.absolute_coords=displayed_plot.vectors[1][0][cindex], displayed_plot.vectors[1][1][cindex]
             contact_point.find_graph_coords(displayed_plot.vectors[1][0], displayed_plot.vectors[1][1])
             contact_point.is_marker=True
-            
+
         print 'Click edges of chunk'
         points=self._measure_N_points(N=2, whatset=1)
         points=[contact_point]+points
+      
         try:
             if self.config['fit_function']=='wlc':
-                params, yfit, xfit, fit_errors = self.wlc_fit(points, displayed_plot.vectors[1][0], displayed_plot.vectors[1][1],pl_value,T, return_errors=True )
+                params, yfit, xfit, fit_errors,qstd = self.wlc_fit(points, displayed_plot.vectors[1][0], displayed_plot.vectors[1][1],pl_value,T, return_errors=True )
                 name_of_charlength='Persistent length'
             elif self.config['fit_function']=='fjc':
-                params, yfit, xfit, fit_errors = self.fjc_fit(points, displayed_plot.vectors[1][0], displayed_plot.vectors[1][1],pl_value,T, return_errors=True )
+                params, yfit, xfit, fit_errors,qstd = self.fjc_fit(points, displayed_plot.vectors[1][0], displayed_plot.vectors[1][1],pl_value,T, return_errors=True )
                 name_of_charlength='Kuhn length'
+            elif self.config['fit_function']=='efjc':
+                params, yfit, xfit, fit_errors,qstd = self.efjc_fit(points, displayed_plot.vectors[1][0], displayed_plot.vectors[1][1],pl_value,T, return_errors=True )
+                name_of_charlength='Kuhn length (e)'                    
             else:
                 print 'No recognized fit function defined!'
-                print 'Set your fit function to wlc or fjc.'
+                print 'Set your fit function to wlc, fjc or efjc.'
                 return
-            
+
         except:
             print 'Fit not possible. Probably wrong interval -did you click two *different* points?'
             return
-        
+
         #FIXME: print "Kuhn length" for FJC
         print 'Fit function:',self.config['fit_function']
         print 'Contour length: ',params[0]*(1.0e+9),' nm'
@@ -458,12 +744,14 @@ class fitCommands:
             print name_of_charlength+': ',params[1]*(1.0e+9),' nm'
             to_dump='persistent '+self.current.path+' '+str(params[1]*(1.0e+9))+' nm'
             self.outlet.push(to_dump)
-        
+
         if fit_errors:
             fit_nm=[i*(10**9) for i in fit_errors]
             print 'Standard deviation (contour length)', fit_nm[0]
             if len(fit_nm)>1:
                 print 'Standard deviation ('+name_of_charlength+')', fit_nm[1]
+        
+        print 'Fit quality: '+str(qstd/np.std(displayed_plot.vectors[1][1][-20:-1]))
             
             
         #add the clicked points in the final PlotObject
@@ -471,51 +759,51 @@ class fitCommands:
         for item in points:
             clickvector_x.append(item.graph_coords[0])
             clickvector_y.append(item.graph_coords[1])
-        
+
         #create a custom PlotObject to gracefully plot the fit along the curves
-                        
+
         fitplot=copy.deepcopy(displayed_plot)
         fitplot.add_set(xfit,yfit)
         fitplot.add_set(clickvector_x,clickvector_y)
-        
+
         #FIXME: this colour/styles stuff must be solved at the root!
         if fitplot.styles==[]:
             fitplot.styles=[None,None,None,'scatter']
         else:
             fitplot.styles+=[None,'scatter']
-        
+
         if fitplot.colors==[]:
             fitplot.colors=[None,None,None,None]
         else:
             fitplot.colors+=[None,None]
-        
+
         self._send_plot([fitplot])
-    
-  
+
+
 
     #----------
-    
-    
+
+
     def find_contact_point(self,plot=False):
         '''
         Finds the contact point on the curve.
-    
+
         The current algorithm (thanks to Francesco Musiani, francesco.musiani@unibo.it and Massimo Sandal) is:
         - take care of the PicoForce trigger bug - exclude retraction portions with too high standard deviation
         - fit the second half of the retraction curve to a line
         - if the fit is not almost horizontal, take a smaller chunk and repeat
         - otherwise, we have something horizontal
         - so take the average of horizontal points and use it as a baseline
-    
+
         Then, start from the rise of the retraction curve and look at the first point below the
         baseline.
-        
+
         FIXME: should be moved, probably to generalvclamp.py
         '''
-        
+
         if not plot:
             plot=self.plots[0]
-        
+
         outplot=self.subtract_curves(1)
         xret=outplot.vectors[1][0]
         ydiff=outplot.vectors[1][1]
@@ -524,7 +812,7 @@ class fitCommands:
         yext=plot.vectors[0][1]
         xret2=plot.vectors[1][0]
         yret=plot.vectors[1][1]
-        
+
         #taking care of the picoforce trigger bug: we exclude portions of the curve that have too much
         #standard deviation. yes, a lot of magic is here.
         monster=True
@@ -537,13 +825,13 @@ class fitCommands:
             else: #move away from the monster
                 monlength-=int(len(xret)/50)
                 finalength-=int(len(xret)/50)
-    
-    
+
+
         #take half of the thing
         endlength=int(len(xret)/2)
-    
+
         ok=False
-        
+
         while not ok:
             xchunk=yext[endlength:monlength]
             ychunk=yext[endlength:monlength]
@@ -553,36 +841,36 @@ class fitCommands:
             if (abs(regr[1]) > 0.1) and ( endlength < len(xret)-int(len(xret)/6) ) :
                 endlength+=10
             else:
-                ok=True  
-                  
-        
+                ok=True
+
+
         ymean=np.mean(ychunk) #baseline
-    
+
         index=0
         point = ymean+1
-    
+
         #find the first point below the calculated baseline
         while point > ymean:
             try:
                 point=yret[index]
-                index+=1    
+                index+=1
             except IndexError:
                 #The algorithm didn't find anything below the baseline! It should NEVER happen
-                index=0            
+                index=0
                 return index
-            
+
         return index
-                        
-    
-    
+
+
+
     def find_contact_point2(self, debug=False):
         '''
         TO BE DEVELOPED IN THE FUTURE
         Finds the contact point on the curve.
-            
+
         FIXME: should be moved, probably to generalvclamp.py
         '''
-        
+
         #raw_plot=self.current.curve.default_plots()[0]
         raw_plot=self.plots[0]
         '''xext=self.plots[0].vectors[0][0]
@@ -594,43 +882,43 @@ class fitCommands:
         yext=raw_plot.vectors[0][1]
         xret2=raw_plot.vectors[1][0]
         yret=raw_plot.vectors[1][1]
-        
+
         first_point=[xext[0], yext[0]]
         last_point=[xext[-1], yext[-1]]
-       
+
         #regr=scipy.polyfit(first_point, last_point,1)[0:2]
         diffx=abs(first_point[0]-last_point[0])
         diffy=abs(first_point[1]-last_point[1])
-        
+
         #using polyfit results in numerical errors. good old algebra.
         a=diffy/diffx
         b=first_point[1]-(a*first_point[0])
         baseline=scipy.polyval((a,b), xext)
-        
+
         ysub=[item-basitem for item,basitem in zip(yext,baseline)]
-        
+
         contact=ysub.index(min(ysub))
-        
+
         return xext,ysub,contact
-        
+
         #now, exploit a ClickedPoint instance to calculate index...
         dummy=ClickedPoint()
         dummy.absolute_coords=(x_intercept,y_intercept)
         dummy.find_graph_coords(xret2,yret)
-        
+
         if debug:
             return dummy.index, regr, regr_contact
         else:
             return dummy.index
-            
-        
+
+
 
     def x_do_contact(self,args):
         '''
         DEBUG COMMAND to be activated in the future
         '''
         xext,ysub,contact=self.find_contact_point2(debug=True)
-        
+
         contact_plot=self.plots[0]
         contact_plot.add_set(xext,ysub)
         contact_plot.add_set([xext[contact]],[self.plots[0].vectors[0][1][contact]])
@@ -639,8 +927,8 @@ class fitCommands:
         contact_plot.styles=[None,None,None,'scatter']
         self._send_plot([contact_plot])
         return
-        
-        
+
+
         index,regr,regr_contact=self.find_contact_point2(debug=True)
         print regr
         print regr_contact
@@ -649,8 +937,8 @@ class fitCommands:
         #nc_line=[(item*regr[0])+regr[1] for item in x_nc]
         nc_line=scipy.polyval(regr,xret)
         c_line=scipy.polyval(regr_contact,xret)
-                     
-        
+
+
         contact_plot=self.current.curve.default_plots()[0]
         contact_plot.add_set(xret, nc_line)
         contact_plot.add_set(xret, c_line)
@@ -658,4 +946,3 @@ class fitCommands:
         #contact_plot.styles.append(None)
         contact_plot.destination=1
         self._send_plot([contact_plot])
-        
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