If , else if statement problem

Hello i guys i have matlab code of traffic generation but in one case i did not understand the if statement, can anyone tell me what is going on in that part please? I mean what is ones inside parenthesis?

HEARTBEAT = 1;
if(1)
    %         P_INDEP = [1 0.8; ...
    %             0 0.2];
    %         P_COORD = [0.1 0.8; ...
    %             0.9 0.2];
    P_INDEP = [1 1; ...
        0 0];
    P_COORD = [0 1; ...
        1 0];
    LAMBDA = [(HEARTBEAT/(SUPPT(2)-SUPPT(1))*DATAPKTINTS/NUMMACHINES); 1];
    % mean arrival rate,, generated data per device in a given time interval.
    PRIORITY = [0;1];
    STARTSTATE=1;
    % overwrite default values
    ALRMDISTIME={'unif',mean(SUPPT)-100,mean(SUPPT)+100};
    % alarm is uniformly issued btw 1700-1900 in time interval
elseif(1)
    P_INDEP = [1 0.8 0.01; ...
        0 0.2 0;
        0 0 0.99];
    P_COORD = [0.1 0.8 0; ...
        0.9 0.2 0.05;
        0 0 0.95];
    LAMBDA = [(HEARTBEAT/(SUPPT(2)-SUPPT(1))*DATAPKTINTS/NUMMACHINES); 1; 0.001];
    PRIORITY = [0;1;0];
    STARTSTATE=3;
    % overwrite default values
    ALRMDISTROX={'unif',mean(SUPPX)-200,mean(SUPPX)+100};
    ALRMDISTROY={'unif',mean(SUPPX)-200,mean(SUPPX)+100};
else
    P_INDEP = [1 0 0.01 0.000001;
        0 0 0 0;
        0 0 0.99 0;
        0 1 0 0.999999];
    P_COORD = [0 0 0 0.000001;
        1 0 0.05 0;
        0 0 0.95 0;
        0 1 0 0.999999];
    LAMBDA = [(HEARTBEAT/(SUPPT(2)-SUPPT(1))*DATAPKTINTS/NUMMACHINES); 1; 0.01; 0];
    PRIORITY = [0;1;0;0];
    STARTSTATE=3;
end

Answer 1

[per isakson]

The if - elseif - else - end control construct makes little sense.

Documentation says:

    if expression, statements, end evaluates an expression, and executes a group of
    statements when the expression is true. An expression is true when its result is
    nonempty and contains only nonzero elements (logical or real numeric). Otherwise,
    the expression is false.

    The elseif and else blocks are optional. The statements execute only if previous
    expressions in the if...end block are false. An if block can include multiple
    elseif blocks.

The expression, (1), is always non-zero thus only the the group of statements after if will be executed.