Basics of MATLAB and Beyond

i =i =123136Vectorised Codematlab is a matrix language, and many of its algorithms are optimisedfor matrices. matlab code can often be accelerated by replacing forand while loops with operations on matrices. In the following example,we calculate the factorial of the numbers from 1 to 500 using a forloop. Create a script m-file called factorialloop.m that contains thefollowing code:for number = 1:500fact = 1;for i = 2:numberfact = fact*i;endy(number) = fact;endWe can time how long this program takes to run by using the stopwatchfunctions tic and toc:>> tic;factorialloop;tocelapsed_time =4.6332which is the time in seconds. The same calculation can be done in muchless time by replacing the internal for loop by the prod function. Createan m-file called factorialvect.m:for number = 1:500y(number) = prod(1:number);endThis version takes about a tenth of the time:>> clear>> tic;factorialvect;tocelapsed_time =0.4331c○ 2000 by CRC Press LLC