Hi Nicolas, The comments in GraphFitChisquare function (TGrph.cxx) says: //*-*-*-*-*-*Minimization function for Graphs using a Chisquare method*-*-*-*-* //*-* ========================================================= // // In case of a TGraphErrors object, ex, the error along x, is projected // along the y-direction by calculating the function at the points x-ex and // x+ex. // // The chisquare is computed as the sum of the quantity below at each point: // // (y - f(x))**2 // ----------------------------------- // ey**2 + ((f(x+ex) - f(x-ex))/2)**2 // // where x and y are the point coordinates Rene Brun On Wed, 11 Sep 2002, Nicolas de Sereville wrote: > Hi Rooters, > > I am fitting TGraphErrors object with my own function without any > problem. My question is how is handled the x error bar in the calculation > of the chisquare? I couldn't find it in the source code. > > Thanks > > Nicolas > > -- > :-------------------------------: > : Nicolas de SEREVILLE : > : C.S.N.S.M. : > : Batiment 104 : > : 91405 ORSAY Campus : > : Tel : (+ 33) (0)1 69 15 52 29 : > : Fax : (+ 33) (0)1 69 15 50 08 : > :-------------------------------: >
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