Department of Engineering

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# Suppressing and controlling output

Matlab is frequently used with vectors and matrices containing hundreds or thousands of entries. In such cases it is a great inconvenience to have the answers written to the terminal. It is easy, however, to prevent Matlab from writing the answer to any calculation: simply terminate a statement by a semi-colon (;) and Matlab will execute it without writing out the result. For example, generate a vector of 100 evenly spaced points between 0 and (remember the semi-colon, and distinguish it from the colons (:) which are used to define the vector conveniently):


t = linspace(0, pi, 100);

Now you can examine the first 10 values, say, by typing t(1:10) (without a semi-colon). If you just type t you will get all 100 points. We can also make a vector of the values of for :

sint = sin(t);

Did you remember the semi-colon?

In engineering we often need to use scientific' notation, in which numbers are written in the mantissa exponent' form . We can make Matlab output results in this form. First let's look at the values in the vector sint near to , say the 49th, 50th, 51st and 52nd entries:


sint(49:52)

Now switch to scientific notation by typing

format short e

and look at those values again. You will see the values to 4 decimal places, with powers of 10 (labelled e' for exponent). If you would like to see the values to the full accuracy with which they are stored in Matlab, type

format long e

and look at them again. If you would like to restore the original format, type

format
`
on its own.

Next: Graphical output Up: Getting started with Matlab Previous: Polynomials
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