diff -r 88a01948450d -r d33698326409 plotting_data/script.rst --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/plotting_data/script.rst Wed Dec 01 16:51:35 2010 +0530 @@ -0,0 +1,218 @@ +.. Objectives +.. ---------- + +.. By the end of this tutorial, you will be able to + +.. 1. Defining a list of numbers +.. 2. Squaring a list of numbers +.. 3. Plotting data points. +.. 4. Plotting errorbars. + + +.. Prerequisites +.. ------------- + +.. 1. getting started with plotting + + +.. Author : Amit + Internal Reviewer : Anoop Jacob Thomas + External Reviewer : + Checklist OK? : [2010-10-05] + +.. #[[Anoop: Add quickref]] +.. #[[Anoop: Slides are incomplete, add summary slide, thank you slide + etc.]] + +=============================== +Plotting Experimental Data +=============================== + +{{{ Show the slide containing title }}} + +Hello and welcome , this tutorial on Plotting Experimental data is +presented by the fossee team. + +{{{ Show the Outline Slide }}} + +.. #[[Anoop: outline slide is missing]] + +Here we will discuss plotting Experimental data. + +1. We will see how we can represent a sequence of numbers in Python. + +2. We will also become familiar with elementwise squaring of such a +sequence. + +3. How to plot data points using python. + +4. We will also see how we can use our graph to indicate Error. + +One needs to be familiar with the concepts of plotting +mathematical functions in Python. + +We will use data from a Simple Pendulum Experiment to illustrate. + +.. #[[Anoop: what do you mean by points here? if you mean the + points/numbered list in outline slide, then remove the usage point + from here.]] + +{{{ Simple Pendulum data Slide }}} + +.. #[[Anoop: slides are incomplete, work on slides and context + switches]] + + +As we know for a simple pendulum length,L is directly proportional to +the square of time,T. We shall be plotting L and T^2 values. + + +First we will have to initiate L and T values. We initiate them as sequence +of values. We define a sequence by comma seperated values inside two square brackets. +This is also called List.Lets create two sequences L and t. + +.. #[[Anoop: instead of saying "to tell ipython a sequence of values" + and make it complicated, we can tell, we define a sequence as]] + +.. #[[Anoop: sentence is incomplete, can be removed]] + +{{{ Show the initializing L&T slide }}} + +Type in ipython shell :: + + L = [0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9] + + t= [0.69, 0.90, 1.19,1.30, 1.47, 1.58, 1.77, 1.83, 1.94] + + +To obtain the square of sequence t we will use the function square +with argument t.This is saved into the variable tsquare.:: + + tsquare=square(t) + tsqaure + array([ 0.4761, 0.81 , 1.4161, 1.69 , 2.1609, 2.4964, 3.1329, + 3.3489, 3.7636]) + +.. #[[Anoop: how do you get the array([ 0.4761 ....]) output?]] + + +Now to plot L vs T^2 we will simply type :: + + plot(L,tsquare,'.') + +.. #[[Anoop: be consistent with the spacing and all.]] + +'.' here represents to plot use small dots for the point. :: + + clf() + +You can also specify 'o' for big dots.:: + + plot(L,tsquare,'o') + + clf() + + +Following are exercises that you must do. + +%% %% Plot the given experimental data with large dots.The data is +on your screen. + +%% %% Plot the given experimental data with small dots. +The data is on your screen + + +Please, pause the video here. Do the exercises and then continue. + + + + + +.. #[[Anoop: Make sure code is correct, corrected plot(L,t,o) to + plot(L,t,'o')]] + + + +.. #[[Anoop: again slides are incomplete.]] + +For any experimental there is always an error in measurements due to +instrumental and human constaraints.Now we shall try and take into +account error into our plots . The Error values for L and T are on +your screen.We shall again intialize the sequence values in the same +manner as we did for L and t + +The error data we will use is on your screen. + +{{{ Show the Adding Error Slide }}} +.. #[[Anoop: give introduction to error and say what we are going to + do]] + +:: + + delta_L= [0.08,0.09,0.07,0.05,0.06,0.00,0.06,0.06,0.01] + delta_T= [0.04,0.08,0.03,0.05,0.03,0.03,0.04,0.07,0.08] + +Now to plot L vs T^2 with an error bar we use the function errorbar() + +The syntax of the command is as given on the screen. :: + + + errorbar(L,tsquare,xerr=delta_L, yerr=delta_T, fmt='b.') + +This gives a plot with error bar for x and y axis. The dots are of +blue color. The parameters xerr and yerr are error on x and y axis and +fmt is the format of the plot. + + +similarly we can draw the same error bar with big red dots just change +the parameters to fmt to 'ro'. :: + + clf() + errorbar(L,tsquare,xerr=delta_L, yerr=delta_T, fmt='ro') + + + +thats it. you can explore other options to errorbar using the documentation +of errorbar.:: + + errorbar? + +Following is an exercise that you must do. + +%% %% Plot the given experimental data with large green dots.Also include +the error in your plot. + +Please, pause the video here. Do the exercise and then continue. + + + + + + + +{{{ Show Summary Slide }}} + +In this tutorial we have learnt : + + + +1. How to declare a sequence of numbers. + +2. Plotting experimental data. + +#. The various options available for plotting dots instead of lines. + +#. Plotting experimental data such that we can also represent error. + + + + {{{ Show the "sponsored by FOSSEE" slide }}} + +.. #[[Anoop: again slides are incomplete]] + +This tutorial was created as a part of FOSSEE project. + +Hope you have enjoyed and found it useful. + +Thank You! +