[Matplotlib-users] linear regression with dates as x axis
Hi all, I have some time series of disk usage that I'd like to do a linear regression on an plot on a nice graph with Mb used on the y-axis and date on the x axis. I tried to use pylab.polyfit(dates, usage) where: dates = [datetime(x, y, z), datetime(a, b, c), ...] usage = [12123234, 2234235235, ...] ...but polyfit doesn't like the dates. How should I do this? Any example of a nice plot and linear regression using matplotlib? cheers, Chris -- Simplistix - Content Management, Batch Processing Python Consulting - http://www.simplistix.co.uk -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] linear regression with dates as x axis
Check out linregress from scipy.stats module. Not sure if it will handle dates. Sample script below: from scipy.stats import pearsonr from scipy.stats import linregress from matplotlib import pyplot as plt import numpy as np sat = np.array([595,520,715,405,680,490,565]) gpa = np.array([3.4,3.2,3.9,2.3,3.9,2.5,3.5]) fig1 = plt.figure(1) ax = plt.subplot(1,1,1) pearson = pearsonr(sat, gpa) plt.scatter(sat,gpa, label=data) # Get linear regression parameters slope, intercept, r_value, p_value, std_err = linregress(sat, gpa) # Format the chart plt.xlabel(SAT Scores) plt.ylabel(GPA) plt.title(Scatter Plot with Linear Regression Fit\nY=a*X + b\na=%0.4f, b=%0.4f % (slope, intercept)) plt.grid() # Create linear regression x values x_lr = sat # Create linear regression y values: Y = slope*X + intercept y_lr = slope * x_lr + intercept print Pearson correlation coefficient: , pearson[0] print Fit x-values: , str(x_lr) print Fit y-values: , str(y_lr) print Fit slope: ,slope print Fit intercept: , intercept plt.plot(x_lr, y_lr, label=fit) plt.legend() plt.show() Regards, Daniel On Jun 13, 2012 12:32 PM, Chris Withers ch...@simplistix.co.uk wrote: Hi all, I have some time series of disk usage that I'd like to do a linear regression on an plot on a nice graph with Mb used on the y-axis and date on the x axis. I tried to use pylab.polyfit(dates, usage) where: dates = [datetime(x, y, z), datetime(a, b, c), ...] usage = [12123234, 2234235235, ...] ...but polyfit doesn't like the dates. How should I do this? Any example of a nice plot and linear regression using matplotlib? cheers, Chris -- Simplistix - Content Management, Batch Processing Python Consulting - http://www.simplistix.co.uk -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] linear regression with dates as x axis
Sorry looks like my smartphone's copy/paste removed carriage return in certain places in the script :-( On Jun 13, 2012 12:32 PM, Chris Withers ch...@simplistix.co.uk wrote: Hi all, I have some time series of disk usage that I'd like to do a linear regression on an plot on a nice graph with Mb used on the y-axis and date on the x axis. I tried to use pylab.polyfit(dates, usage) where: dates = [datetime(x, y, z), datetime(a, b, c), ...] usage = [12123234, 2234235235, ...] ...but polyfit doesn't like the dates. How should I do this? Any example of a nice plot and linear regression using matplotlib? cheers, Chris -- Simplistix - Content Management, Batch Processing Python Consulting - http://www.simplistix.co.uk -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
