Archive for the ‘Controls’ Category

while Repeat statements an indefinite number of times.
The general form of a while statement is:

while expression
statements
END

The statements are executed while the real part of the expression
has all non-zero elements. The expression is usually the result of
expr rop expr where rop is ==, <, >, <=, >=, or ~=.

The BREAK statement can be used to terminate the loop prematurely.

For example (assuming A already defined):

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E = 0*A; F = E + eye(size(E)); N = 1;
while norm(E+F-E,1) > 0,
E = E + F;
F = A*F/N;
N = N + 1;
end

See also for, if, switch, break, end.

return Return to invoking function.
return causes a return to the invoking function or to the keyboard.
It also terminates the KEYBOARD mode.

Normally functions return when the end of the function is reached.
A return statement can be used to force an early return.

Example

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function d = det(A)
if isempty(A)
d = 1;
return
else
...
end

See also function, keyboard.

elseif IF statement condition.
elseif is used with IF. The statements after the elseif are
executed if the expression is true and all the preceding IF and
elseif expressions are false. An expression is considered true if
the real part has all non-zero elements.

elseif does not need a matching END, while ELSE IF does.

The general form of the IF statement is
IF expression
statements
elseif expression
statements
ELSE
statements
END

See also if, else, end.