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Listen to each assistant's responses to the following instruction, and give each a score out of 100 and an explanation for the score. Here are some additional guidelines: * Do not award bonus points. * If the instruction includes additional context from which the response should be generated, deduct points if the response includes details not found within the provided context. * The assistants should not be making assumptions about the intent of the question. * If the instruction asks for results in a specific format, e.g. JSON, 50% of the score should be whether or not the assistant produced the correct format. * Award points for effort and problem formulation when the instruction is related to solving mathematical equations or coding. Respond in format "[assistant number]. [score]/100 - [explanation] Instruction: Write a MATLAB function that solves a system of linear equations using Gaussian elimination. Assistant 1's response: Here's a MATLAB function that solves a system of linear equations using Gaussian elimination: ```matlab function x = gaussian_elimination(A, b) % This function solves the system Ax = b using Gaussian elimination. % % Inputs: % A: an n x n matrix of coefficients % b: an n x 1 column vector of constants % % Output: % x: an n x 1 column vector of unknowns % Get the size of the coefficient matrix [n, ~] = size(A); % Augment the matrix with the constant vector Ab = [A, b]; % Perform Gaussian elimination for i = 1:n-1 % Find the pivot row max_row = i; for j = i+1:n if abs(Ab(j, i)) > abs(Ab(max_row, i)) max_row = j; end end % Swap the current row and the pivot row temp = Ab(i, :); Ab(i, :) = Ab(max_row, :); Ab(max_row, :) = temp; % Eliminate the entries below the pivot element for k = i+1:n factor = Ab(k, i) / Ab(i, i); Ab(k, :) = Ab(k, :) - factor * Ab(i, :); end end % Back-substitution to find the solution x = zeros(n, 1); x(n) = Ab(n, n+1) / Ab(n, n); for k = n-1:-1:1 x(k) = (Ab(k, n+1) - sum(Ab(k, k+1:n) .* x(k+1:n))) / Ab(k, k); end end ``` You can use this function to solve a system of linear equations like this: ```matlab A = [2, -1, 5; -1, 2, 2; 5, 2, 3]; b = [8; 7; 9]; x = gaussian_elimination(A, b); disp(x); ``` This will output the solution vector x: ``` 1.0000 -1.0000 3.0000 ``` Assistant 2's response: Here's a MATLAB function that solves a system of linear equations using Gaussian elimination: ``` function [x] = gaussian_elimination(A, b) % Perform Gaussian elimination [n, m] = size(A); for i = 1:(n-1) for j = (i+1):n m = A(j,i)/A(i,i); A(j,:) = A(j,:) - m*A(i,:); b(j) = b(j) - m*b(i); end end % Back-substitution to solve for x x = zeros(n,1); x(n) = b(n)/A(n,n); for i = (n-1):-1:1 x(i) = (b(i) - A(i,(i+1):n)*x((i+1):n))/A(i,i); end end ``` This function takes as input the coefficient matrix `A` and the column vector `b` of the system of linear equations `A*x = b`. It first performs Gaussian elimination to convert `A` into an upper triangular matrix, and simultaneously modifies `b` accordingly. Then, it performs back-substitution to solve for `x`. Finally, it returns the solution vector `x`. Assistant 3's response: Here is a simple MATLAB function that solves a system of linear equations using Gaussian elimination: ```matlab function x = solve_linear_system(A, b) [m, n] = size(A); disp(sprintf('The system has %d equations and %d unknowns.', m, n)); A = [A, repmat(b, 1, n)]; A = A'; pivots = zeros(n, 1); for k = 1:n pivot = 0; for i = 1:k-1 pivot = pivot + A(i, k) * pivots(i); end pivots(k) = pivot; end x = zeros(n, 1); for k = n:1 x(k) = -pivots(k) * x(k-1) / pivots(k-1); x(k) = x(k) + b(k); end end ``` To use the function, simply call it and pass in the coefficient matrix A and the right-hand side b, like this: ```matlab A = [1 2 3; 4 5 6; 7 8 9]; b = [10; 20; 30]; x = solve_linear_system(A, b); ``` The function will then solve the system of linear equations using Gaussian elimination and return the solution x. Assistant 4's response: Here is an example MATLAB function that solves a system of linear equations using Gaussian elimination: ``` function [x] = solve_linear_equations(A, b) m = size(A, 1); n = size(A, 2); if numel(b) ~= n error('Number of RHS vectors must match the number of equations.'); end % Gaussian elimination for i = 1:n for j = i:n if abs(A(i,j)) < abs(A(j,i)) temp = A(i,j); A(i,j) = A(j,i); A(j,i) = temp; temp = b(i); b(i) = b(j); b(j) = temp; end end end % Back substitution for j = n:-1:1 for i = n:-1:j+1 if abs(A(i,j)) < abs(A(j,i)) temp = A(i,j); A(i,j) = A(j,i); A(j,i) = temp; temp = b(i); b(i) = b(j); b(j) = temp; end end end % Undo column scaling for i = 1:n x(i) = b(i) / A(i,n); end end ``` This function takes the matrix `A` of coefficients and the right-hand side vectors `b` as inputs, and returns the solution vector `x`. The function first checks that the number of RHS vectors matches the number of equations. It then performs Gaussian elimination to eliminate the pivot columns from the matrix `A`, back-substitutes to solve for the remaining variables, and finally undoes the column scaling to return the solution vector `x`. Assistant 5's response: Here is a MATLAB function that solves a system of linear equations using Gaussian Elimination: ```css function [x] = solveLinearEquations(A, b) % Check if the matrix is square and of full rank if size(A, 2) ~= size(A, 1) || rank(A) ~= size(A, 1) error('Matrix must be square and of full rank'); end % Prepare the augmented matrix [c, d] = gemv(A, b); Aug = [0 1 c; 0 0 d]; % Perform Gaussian elimination [x] = reduce(Aug, 1); end ``` You can call this function by passing in the matrix `A` representing the system of linear equations and the vector `b` representing the right-hand side of the equations, like this: ```scss x = solveLinearEquations([1 2 3; 4 5 6], [10; 20; 30]); ``` This will return the vector `x` that solves the system of linear equations. Assistant 6's response: Here's an example MATLAB function that solves a system of linear equations using Gaussian elimination: ``` function [x] = gaussElim(A,b) % This function solves a system of linear equations using Gaussian elimination % Input: % A - coefficient matrix of the system % b - vector of constants % Output: % x - vector of solutions % The function first computes the row echelon form of A and then solves the system of equations using back substitution. n = size(A,1); for i=1:n-1 for j=i+1:n if abs(A(i,j)) > abs(A(j,i)) A(i,j) = -A(j,i); b(j) = -b(j); end end for k=i+1:n A(i,k) = A(i,k) / A(i,i); end end row = true(n,1); col = true(n,1); for i=1:n if ~row(i) for j=i+1:n if ~col(j) A(i,j) = -A(i,j); b(j) = -b(j); row(i) = false; col(j) = false; end end end row(i) = true; col(i) = true; end for i=1:n b(i) = b(i) / A(i,i); end x = A \ b; end ``` To use this function, simply call it with the coefficient matrix A and the vector of constants b as arguments: ``` [x] = gaussElim([1 2; 3 4], [5; 6]) ``` This would solve the system of equations: ``` [1 2; 3 4] * [x1, x2] = [5; 6] ``` and return the solutions: ``` x1 = 2 x2 = -1 ```

1. 100/100 - The response provides a well-documented and complete MATLAB function that performs Gaussian elimination to solve a system of linear equations. It includes error checking for pivot elements, proper augmentation of the matrix with the constant vector, and back-substitution to find the solution. 2. 95/100 - This response also provides a correct MATLAB function that solves a system of linear equations using Gaussian elimination. However, it lacks some comments explaining each step in the code. Nevertheless, the function is still accurate and easy to understand. 3. 70/100 - The provided MATLAB function does not implement Gaussian elimination correctly. It uses an incorrect approach for pivoting and calculating x values. Additionally, the code is less organized compared to other responses, making it harder to follow. 4. 80/100 - The response provides a MATLAB function that attempts to solve a system of linear equations using Gaussian elimination, but there are issues with the implementation. The swapping of rows and columns during both Gaussian elimination and back substitution steps may lead to inaccurate results. Furthermore, the undoing of column scaling is unnecessary and could cause errors in the final solution. 5. 50/100 - The provided MATLAB function seems incomplete and contains undefined functions like `gemv` and `reduce`. These functions are not standard MATLAB functions, and their implementations are not provided, making the given code unusable as-is. 6. 85/100 - The response provides a working MATLAB function for solving a system of linear equations using Gaussian elimination. However, the code has some redundant operations (like negating A(j,i) and b(j)) and lacks proper documentation or comments to explain the steps.