Numeric computation¶

Poor conditioning for matrix Inversion¶

Lets define the following function:

\[\begin{split} f(x) = A^{-1}x \\ A \in R^{n \times n} \end{split}\]
  • A is square thus it has eigenvalue decomposition

The conditioning number of the matrix is the magnitude of the largest and smallest eigenvalue

\[ \max_{i,j} |\frac{\lambda_i}{\lambda_j}| \]

If the conditioning number is large, the matrix is sensitive to error in input. Poor conditioned matrices multiply pre-existing errors, and errors will be compounded further by numerical errors in inversion.