#!/usr/bin/python

from pylab import *

y, x = loadtxt("FeAl28-sample1-2.XLS",usecols=(2,3),unpack=True)[:,5:-2]
x = -x

plot(x,y)

data = array(ginput(2))

a,b = sort(data[:,0])
c = b-a
xx = array([a-c/5,b+c/5])

m = (x>=a) & (x<=b)

plot(x[m], y[m], lw=5)

a,b = polyfit(x[m], y[m], 1)

plot(xx,a*(xx+b/a))

figure()
plot(x+b/a-y/a, y)

show()