Return solves a system of linear equations \A * X = B, using LDL factorization.
The pivot indices. If ipiv(k) > 0, then rows and columns k and ipiv(k) were interchanged and D(k, k) is a '1 x 1' diagonal block. If ipiv(k) = ipiv(k + 1) < 0, then rows and columns k+1 and -ipiv(k) were interchanged and D(k:k+1, k:k+1) is a '2 x 2' diagonal block.
Matrix in witch lower triangular matrix is 'L' part of factorization, diagonal is 'D' part.
uplo = 'U': Upper triangle is stored; 'L': lower triangle is stored.
Consist LDL factorization;