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FOR Repeat statements a specific number of times.
The general form of a FOR statement is:
FOR variable = expr, statement, ..., statement END
The columns of the expression are stored one at a time in
the variable and then the following statements, up to the
END, are executed. The expression is often of the form X:Y,
in which case its columns are simply scalars. Some examples
(assume N has already been assigned a value).
for R = 1:N
for C = 1:N
A(R,C) = 1/(R+C-1);
end
end
Step S with increments of -0.1
for S = 1.0: -0.1: 0.0, do_some_task(S), end
Set E to the unit N-vectors
for E = eye(N), do_some_task(E), end
Long loops are more memory efficient when the colon expression appears
in the FOR statement since the index vector is never created.
The BREAK statement can be used to terminate the loop prematurely.
See also PARFOR, IF, WHILE, SWITCH, BREAK, CONTINUE, END, COLON.
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IF Conditionally execute statements.
The general form of the IF statement is
IF expression
statements
ELSEIF expression
statements
ELSE
statements
END
The statements are executed if the real part of the expression
has all non-zero elements. The ELSE and ELSEIF parts are optional.
Zero or more ELSEIF parts can be used as well as nested IF's.
The expression is usually of the form expr rop expr where
rop is ==, <, >, <=, >=, or ~=.
Example
if I == J
A(I,J) = 2;
elseif abs(I-J) == 1
A(I,J) = -1;
else
A(I,J) = 0;
end
See also RELOP, ELSE, ELSEIF, END, FOR, WHILE, SWITCH.
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