****************** Matrix Scaling ****************** :: Matrix scaling = {char_string} ----------------------- Description / Usage ----------------------- This optional card selects a scaling for the linear matrix system solution step.Valid options for {char_string} are listed below. none No scaling is performed. This is the default if no *Matrix Scaling* card is present. Jacobi Point Jacobi scaling is performed. BJacobi Block Jacobi scaling is performed if the underlying matrix format is VBR. If the MSR matrix format is used, the scaling reverts to point Jacobi. row_sum Scale each row so the sum of the magnitudes of the nonzero elements is 1. sym_diag Symmetric scaling so that diagonal elements are 1. sym_row_sum Symmetric scaling using the matrix row sums. If the *Matrix Scaling* card is omitted, the default selection is **none.** ------------ Examples ------------ Following is a sample card: :: Matrix scaling = sym_diag ------------------------- Technical Discussion ------------------------- All of these scalings are supplied via the Aztec library and thus will not affect the linear systems that are solved by other means (using **front**, for example). In an odd twist of fate, the linear system always undergoes a row sum scaling (equivalent to the **row_sum** option) before these other scalings are applied. Note that when a nontrivial scaling is selected, the matrix is overwritten with a rescaled system.