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Matrix determinant

Avoid using `det`

to examine if a matrix is
singular because of the following limitations. Use `cond`

or `rcond`

instead.

Limitation | Result |
---|---|

The magnitude of the determinant is typically unrelated to the condition number of a matrix. | The determinant of a matrix can be arbitrarily large or small without changing the condition number. |

| The determinant calculation is sometimes numerically
unstable. For example, |

`det`

computes the determinant from the triangular
factors obtained by Gaussian elimination with the `lu`

function.

[L,U] = lu(X) s = det(L) % This is always +1 or -1 det(X) = s*prod(diag(U))