Arguments

AP

(input/output) REAL or COMPLEX array, shape $(:)$ with $size({\bf AP}) = n(n+1)/2$, where $n$ is the order of $A$.
On entry, the upper or lower triangle of matrix $A$ in packed storage. The elements are stored columnwise as follows:

$$\begin{array}{c\vert c\vert c} A_{i,j} & i,j & {\bf UPLO} ... ... \leq i \leq n \end{array} & \mbox{ 'L'} \\ \hline \end{array}$$

On exit, the factor $U$ or $L$ from the Cholesky factorization $A = U^HU$ or $A = LL^H$, in the same storage format as $A$.

B

(input/output) REAL or COMPLEX array, shape $(:,:)$ with $size({\bf B},1) = n$ or shape $(:)$ with $size({\bf B}) = n$.
On entry, the matrix $B$.
On exit, the solution matrix $X$.

UPLO

Optional (input) CHARACTER(LEN=1)


Default value: 'U'.

INFO

Optional (output) INTEGER.


If INFO is not present and an error occurs, then the program is terminated with an error message.

References: [1] and [17,9,20].