Plotting Graph Functions using Gnuplot

arslanburney at gmail.com arslanburney at gmail.com
Thu Jun 12 17:01:17 CEST 2008


Hello. Needed some help again. Im trying to calculate the best fit
line here. Given a set of points in a list. However, wirte in the end
where i plot the line it tells me tht the variable is not defined.
Either try correcting this or tell me a subsitute that i could use.
Thnks. Heres the code:


#File name Bestfit.py

import Gnuplot

def bestfit(uinput):

    if not isinstance(uinput, list):
        return False

    else:


            sigmax = sigmay = sigmaxy = sigmaxwhl = sigmaxsq = 0

            for i in range(len(uinput)):

                n = len(uinput)

                sigmax = uinput[i][0] + sigmax
                sigmay = uinput[i][1] + sigmay
                sigmaxy = uinput[i][0] * uinput [i][1] + sigmaxy
                sigmaxwhl = sigmax * sigmax
                sigmaxsq = uinput[i][0] * uinput[i][0] + sigmaxsq
                sigmaxsigmay = sigmax * sigmay

                num = sigmaxsigmay - (n * sigmaxy)
                den = sigmaxwhl - (n* sigmaxsq)

                num2 = (sigmax * sigmaxy) - (sigmay * sigmaxsq)


            gradient = num / den

            intercept = num2 / den

            m = gradient
            c = intercept


            y = m*x + c
            plot (y)


-------

import Bestfit

Bestfit.bestfit([(2,3), (3,8), (5,7), (4,9)])



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