# Computing the Inverse of a Positive Definite Matrix (potri)

potri computes the inverse of a real symmetric positive definite matrix A using the Cholesky factorization computed by trf_.

## Real Variant

The Cholesky factorization reads $$A = U^T U$$ or $$A = L L^T$$.

 A (input/output) real valued SyMatrix The triangular factor $$U$$ or $$L$$ from the Cholesky factorization $$A = U^T U$$ or $$A = L L^T$$, as computed by potrf.

Return value:

 i=0 Successful exit. i>0 The $$i$$-th diagonal element of the factor $$U$$ or $$L$$ is zero, and the inverse could not be computed.

## Complex Variant

The Cholesky factorization reads $$A = U^H U$$ or $$A = L L^H$$.

 A (input/output) complex valued HeMatrix The triangular factor $$U$$ or $$L$$ from the Cholesky factorization $$A = U^H U$$ or $$A = L L^H$$, as computed by potrf.

Return value:

 i=0 Successful exit. i>0 The $$i$$-th diagonal element of the factor $$U$$ or $$L$$ is zero, and the inverse could not be computed.