21: Computation of Determinants
October 31, 2016
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Because the computation of matrix determinants by cofactor expansion (Laplace expansion) is computationally very expensive — for example, computing the determinant of an matrix by this method requires over multiplications — other methods are usually used.
For instance, the simple method of using Gaussian elimination to reduce the matrix to its upper-triangular form, then taking the product of the diagonal to obtain the determinant, is just in multiplications. Other, even less expensive algorithms exist as well, such as the Bareiss algorithm.