On receiving an instruction, each node executes it on its own data. Column blocking can be performed at the user's discretion to improve load balance and increase parallelism. Scaling is not used in our current CM-5 code, but should perhaps be made available in our toolbox for the informed user. This is due in part to the elimination of blocking techniques when pivoting, as columns must be processed sequentially. Gaussian elimination with or without partial pivoting is available to compute LU factorizations and perform back substitution to solve a system of equations.
Matrix inversion is performed by solving the system .
The entries of random test matrices were uniformly distributed on . Table 3 shows the measured results of the backward accuracy, total CPU time and megaflops rate. The second column of the table is the backward error, the number of Newton iterations and the number of the Newton-Schulz iterations, respectively.