Plotting Graphs + Bestfit lines

[arslanburney at gmail.com]

Hello. Ive got two functions here. Somehow the program does not go in
to the second function wehn i call it. The bestfit function. Could
some1 help me identify the problem. Heres the code:


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

            p = Gnuplot.Gnuplot()
            p.plot ('%f * x+%f'%(m,c))

            return p

def plot(original, expected, actual):


    if not isinstance(original, list):
        return False

    else:

        gp = Gnuplot.Gnuplot()
        gp('set data style lines')



        # Make the plot items
        plot1 = Gnuplot.PlotItems.Data(original, title="Original")
        plot2 = Gnuplot.PlotItems.Data(expected, title="Expected")
        plot3 = Gnuplot.PlotItems.Data(actual, title="Acutal")


        gp.plot(plot1, plot2, plot3)
        bestfit(expected)
        bestfit(actual)

        return gp


-------

import Combine           #The name of my file...

gp = Combine.plot( [(2,3), (4,8), (5,9), (6,2)], [(1,7), (3,3), (4,5),
(5,6)], [(1,3), (3,10), (4,8), (7,9) ] )
raw_input()