Lec-10 Manipulations of Matlab Matrices

Built-in functions The chapter will be covered quickly There are quite a few built-in functions in MATLAB – If you can think of it, it is probably available – To find documentation, use Google to find documentation: e.g. google “sine matlab” google “standard deviation matlab”

Nesting of functions Just in regular math where one can use f(g(x)) Arguments can be scalars, vectors or matrices

Parameters (Arguments) Parameter and argument are almost synonyms sqrt(x) is a function with one parameter If we call sqrt as sqrt(4) 4 is the argument passed to the parameter sin(x) is a function of one parameter too If we call it as sin(sqrt(4)) It’s the value of sqrt(4) is passed as the argument to its one parameter.

Functions with multiple arguments We have encountered linspace(1,10,100) rand(3,4) rem(12.1,5.0) ans= 2.1

Matlab help You can use MATLAB help If you don’t know the name, use Google. Try “help” tab in MATLAB window.

More MATLAB Functions

Rounding Functions

Trigonometric Functions sin(x) sine of x expressed in radians) cos(x), tan(x) sind(x) sine of x in degrees cosd(x) tand(x) etc.

Data Analysis Functions max (maximum) min (minimum) mean (average) median sum (sum total of elements) prod (product) sort (sort elements) cumsum, cumprod (cummulative sum, prod)

mean

sum and cumsum

Example of mean with vector output

If you can imagine it, it is likely there

Sorting

Try Try out at least 10 of the functions I just described with both scalar and vector inputs – At least one of fix, round, ceil – At least one of the trig functions in radians and degrees. – Some of the sum, prod, cumsum – Try log of exp – Try max with vector output Compute the average location of the maximum values from the columns of the matrix magic(5) – Sort the rows of magic(5) according to the third colum n

Problem Problem 3.20: Throw one die Throw two dice Throw two dice 100 times along with the total of each throw Histogram the sum

Problem >> one=floor(rand(1)*6+1) one = 5 >> two=floor(rand(1,2)*6+1) two = 2 4 >> sim=floor(rand(2,10).*6+1) sim = >> total=sum(sim) total = >> hist(total);

Problem