Parallel strategies for computing the orthogonal factorizations used in the estimation of econometric models

Parallel strategies based on compound disjoint Givens rotations are propose d for computing the main two factorizations that are used in the solution o f seemingly unrelated regression and simultaneous equations models. The fir st factorization requires the triangularization of a set of upper-trapezoid als after deleting columns. The second factorization is equivalent to updat ing a lower-triangular matrix with a matrix having a block lower-triangular structure. Theoretical measures of complexity and examples are used for co mparing and investigating the various parallel strategies.