Identify the error in this partial pivoting implementation:
def partial_pivot(A, b, col):
    n = len(A)
    max_row = col
    for i in range(col, n): # Line A
        if abs(A[i][col]) > abs(A[max_row][col]):
            max_row = i

    if max_row != col:
        A[col], A[max_row] = A[max_row], A[col] # Line B
        b[col], b[max_row] = b[max_row], b[col]

    return abs(A[col][col]) > 1e-15 # Line C

Question

Identify the error in this partial pivoting implementation:

def partial_pivot(A, b, col):

    n = len(A)

    max_row = col

    for i in range(col, n):  # Line A

        if abs(A[i][col]) > abs(A[max_row][col]):

            max_row = i

    if max_row != col:

        A[col], A[max_row] = A[max_row], A[col]  # Line B

        b[col], b[max_row] = b[max_row], b[col]

    return abs(A[col][col]) > 1e-15  # Line C

Answer

Line B: Row swapping syntax is incorrect

Answer

Should check if A[max_row][col] is zero before swapping

Answer

Line C: Should return the pivot value, not a boolean

Answer

Line A: Should start from col+1 instead of col

Answer

No error in the code

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