15.1.14  Testing positive definiteness of a symmetric matrix

The isposdef command checks whether the given symmetric matrix A∈ℝ^{n× n} is positive definite, i.e. whether x^TAx>0 for all vectors x∈ℝⁿ.

isposdef takes a symmetric matrix A as its only argument and returns true if A is positive definite and false otherwise. Note that this procedure does not check whether A is symmetric.

Example