repo/traffic-intelligence: python/utils.py comparison

added utility to calibrate polynoms and plot

author	Nicolas Saunier <nicolas.saunier@polymtl.ca>
date	Mon, 20 Feb 2012 19:32:27 -0500
parents	2788b2827670
children	ab1a11176d7b

comparison

equal deleted inserted replaced

-:c91c8fd8bf1e
+:ca9d9104afba
 win = ones(width,'d')
 result = convolve(win/width,array(inputSignal),'same')
 result[:halfWidth] = inputSignal[:halfWidth]
 result[-halfWidth:] = inputSignal[-halfWidth:]
 return result
+def linearRegression(x, y, deg = 1, plotData = False):
+'''returns the least square estimation of the linear regression of y = ax+b
+as well as the plot'''
+from numpy.lib.polynomial import polyfit
+from matplotlib.pyplot import plot
+from numpy.core.multiarray import arange
+coef = polyfit(x, y, deg)
+if plotData:
+def poly(x):
+result = 0
+for i in range(len(coef)):
+result += coef[i]*x**(len(coef)-i-1)
+return result
+plot(x, y, 'x')
+xx = arange(min(x), max(x),(max(x)-min(x))/1000)
+plot(xx, [poly(z) for z in xx])
+return coef
 #########################
 # plotting section
 #########################

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