Write a function in MATLAB that takes as input an n×1 vector p of rearranged int

Question

Write a function in MATLAB that takes as input an n×1 vector p of rearranged integers from 1 to n representing a permutation matrix P whose i-th row is the p(i)-th row of the identity matrix; an n×n matrix B whose upper triangular portion stores U and strictly lower triangular portion stores L of the LU factorization of the matrix P A; and an n×1 vector b. Have this function output the solution to Ax = b. Use only basic programming. Only submit the code, but to make sure your code works, if you input p = [3; 1; 2], B = [2, 1, 3; 0.4, 3, 3; 0.5, 0.2, 4] and b = [2; 1; 1], you should output x = [0.53; 0.83; 0.30].

Explanation / Answer

%find x

function x=findX(n, p, B,b)

%create A

A=zeros(n,n);

%use loop to get A

for kk=1:n

       %Find kkth row of A

       A(kk,:)=B(p(kk),:);

%end

end

%find x

x=A

%end of findX()

%sample run

p = [3;1;2] ;

B = [2 -1 3;-0.4 -3 3;0.5 -0.2 4] ;

b = [2;-1;1];

%call to findX()

x=findX(3, p, B, b)

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