Level one Matlab sessions in term 1 of 2015/6

Customising the set-up with startup.m with the creation of H:\Matlab_Level1. Using Matlab as a calculator in the command window. Practice with forming expressions, the rules of precedence and the use of brackets. The scientific notation of numbers, e.g. -5.2e-6. Some the standard functions, e.g. sqrt, exp, sin, cos, tan and abs. The use of variables and assignment statements. Using the editor to create script files and practice in the cycle of creating a script, running the scripting, editing again, running again etc. Comment statements. A script to solve a quadratic equation.

Examples of for loops to repeat statements. The syntax involving the colon for the list of values to use. Using the variable in the loop with examples using fprintf to neatly format the output. The for loop syntax. Examples to compute sums and products (the factorial). The if-statement and the if-else construction. The comparison operators, e.g. == etc. The use of the break statement to leave a loop before all values have been considered.

Recap of the syntax of a for--loop and a if--else block and an example of using break in the computation of factorials up to a certain size.

Creating vectors by listing the entries between [ and ]. Row vectos, column vectors and the transpose. Creating vectors with equally spaced entries use the colon way, e.g. a:h:b, and also using linspace, e.g. linspace(a, b, n). Using the entries of a vector and changing individual entries and the index end for the last entry. Adding vectors and multiplying by a scalar. Examples of entry-wise operations and using the standard functions in a vectorised way.

The use of plot in the plot(x, y) form and the use of figure to control the window in which the graphics is shown. The use of axes equal when plotting a circle. Two plots together and using a different line type. Adding labels, controlling the size of the font used, controlling the line width and adding a title. Using clf and the hold on and hold off mechanism to do things separately. Saving the plot as a PDF and also saving in other formats. The `copy figure' mechanism to paste into a Word document and comments about including a PDF in Word. Changing the size of the figure window.

Constructing matrices by putting the entries between square brackets. Referring to entries and blocks of entries such as a row or a column and changing these entries with assignment statements. An example of swapping rows. Converting to a column vector storage of everything with a statement such as y=y(:). Brief mention of entry-wise operations. Matrix operations such as multiplying by a scalar and adding. The matrix product with examples of multiplying vectors and matrices of compatible sizes. Solving linear equations with the backslash operation, i.e. x=A\b. The functions zeros, ones and eye which create matrices. The functions size, det, inv and rref.

Some of the examples in the session are taken from your MA1720 problems.

One line functions.

function m-files and the use with the following examples. The case of tan(x/4)-1 and discussion of the use of the function. A function to get all n roots of a complex number involving two input arguments and one output argument which is a vector. In this case the entries have type complex. A function get all solutions of a quadratic equation involving 3 input arguments and two output arguments.

Adding comments which are displayed with the help and doc commands.

The function file syntax in general.

A function to implement the bisection method which involves a function as one of the arguments.

Coding Style

Miscellaneous links