******************************** Matrix Factorization Overlap ******************************** :: Matrix factorization overlap = {char_string} ----------------------- Description / Usage ----------------------- This optional card determines how much matrix factorization overlap occurs with other processors. This specification is only relevant for parallel computations. The valid options for {char_string} are: none No augmentation is performed, equivalent to a setting of k=0. This is the default. diag Augment the processor’s local matrix to include the diagonal (MSR) or diagonal blocks (VBR) for external rows. k Augment the processor’s local matrix to include external rows. The rows are selected by examining non-zero columns from the current local system that refer to offprocessor unknowns, and including the rows associated with those off-processor unknowns. This process is repeated *k* times, where k > 0. When complete, all non-zero columns whose associated rows have not been included are discarded. A value of 0 is equivalent to a setting of none. If the *Matrix factorization overlap* card is omitted, the default is **none.** ------------ Examples ------------ Following is a sample card: :: Matrix factorization overlap = 1 ------------------------- Technical Discussion ------------------------- This optional card determines how much a processor’s local matrix is to be augmented with information from adjacent processors during the approximate factorizations used to build preconditioners. This card should be omitted or given a value of **none** for serial executions.