Question

Given:

function f = fibonacci(n)

% FIBONACCI Fibonacci sequence

% f = FIBONACCI(n) generates the first n Fibonacci numbers.

f = zeros(n,1);

f(1) = 1;

f(2) = 2;

for k = 3:n

f(k) = f(k-1) + f(k-2); end

AND

function f = fibnum(n)

if n <=1

f =1;

else

f = fibnum(n-1) + fibnum(n-2);

end

In Matlab, modify fibonacci.m and fibnum.m to compute the following sequence.

dn = 0, n<=0

d1 = 1,

d2 = 1

and, for n > 2,

dn = dn−1 + dn−2 − dn−7

Answer 1

Modified MATLAB Code:

function d = fibonacci(n)
    d = zeros(n,1);
    d(1) = 1;
    d(2) = 1;
    
    for k = 3:min(n,7)
        d(k) = d(k-1) + d(k-2);
    end
    
    for k = 8:n
        d(k) = d(k-1) + d(k-2) - d(k-7); 
    end
    

function d = fibnum(n)
    if n <= 0
        d = 0;
    elseif n <= 2
        d = 1;
    else
        d = fibnum(n-1) + fibnum(n-2) - fibnum(n-7);
    end

Please refer to the following picture for the sample execution of the above code: