# Maple Flow Control

We know what tools we need from the Matlab page. The difference between Matlab and Maple flow control is generally that Maple is a bit more verbose than Matlab.

## If

The basic syntax is

if conditional then statement sequence;
elif conditional then statement sequence;
else statement sequence;
end if;
As always, the elif and else are optional.

The conditionals have a similar form to those in other languages. There are a few differences. First, conditionals in Maple do not have a truth value outside of the "if" statement context. In other words, the expression "5>2" has no truth value in Maple, but if 5>2 then c:=3; end if; has meaning. If you want to find the truth value of a conditional outside of an "if" statement, you must use the evalb function. Here is an example.

5=3+2; 5 = 5 evalb(5=3+2); true if 5>2 then x:=3; elif 5=2 then x:=103; end if; x := 3

It is worth a special note that Maple uses := for the assignment operator, which frees up = to be used to test equality. This differs from many other languages, which typically use == for that purpose. A table summarizing logical operators follows.

SymbolMeaning
=Is Equal To
<>Is Not Equal To
>Is Greater Than
>=Is Greater Than Or Equal To
<Is Less Than
<=Is Less Than Or Equal To
andLogical And
orLogical Or

## For

Maple has a for loop construction, just like every other language. The syntax is a bit different, however.
for variable from expression to expression do
statement sequence
end do;

You will find this to be fairly intuitive.

for i from 1 to 10 x[i] := i: end do; y := 0: for j from x[3] to x[3]^2 do y := y+j: end do; the_answer_to_life_the_universe_and_everything:=y; the_answer_to_life_the_universe_and_everything:=42

Note that the task of the first loop could have been done more easily using
x:=[seq(i,i=1..10)];

Assignment 6 is posted.

The midterm exam will take place on Friday, 12 October. As always, you are permitted any paper notes you find useful, but no electronic devices are allowed. The test is cumulative, but emphasizes the material covered in the last fours weeks. A sample exam is available.

You need to install Matlab on your computer by Wednesday. You do not need Simulink or any particular toolboxes, though you might find the Symbolic toolbox useful at some time in the future (not in this class).

Department of Mathematics, PO Box 643113, Neill Hall 103, Washington State University, Pullman WA 99164-3113, 509-335-3926, Contact Us