B.3. FMS Matrix Files

FMS offers three options for storing and processing the matrix data. The FMS Parameter MFMAT is used to select which option you want.

The options are:

	MFMAT=1: Profile Solver Accounts for the sparsity of matrix [A] on an equation by equation basis. Typical applications include finite element and finite difference programs. This is the default for sparse matrices.
	MFMAT=2: Block Solver Divides the matrix [A] into square blocks, accounting for sparsity on a block by block basis. This solver uses industry standard BLAS3 kernels and provides excellent I/O performance on extremely large problems. Typical applications include boundary integral and moment method programs. This is the default for full matrices.
	MFMAT=3: Slab Solver Extends the functionality of the Block Solver by providing full column partial pivoting for full nonsymmetric matrices. You must explicitly set MFMAT to select this option.

When you create a matrix file, FMS completes the Matrix File Attribute List , LUA(25), which you provide. This array contains all the information FMS needs to manage the matrix file.

FMS uses four files to store the data for each matrix:

Lower Triangle Data File, LUA(1)
Stores the terms in the lower triangle [AL].
Diagonal Data File, LUA(2)
Stores the terms on the diagonal as a single vector, {D}. You may read and write this data using FMSRED and FMSWRT.
Upper Triangle Data File, LUA(3)
Stores the terms in the upper triangle [AU]. This file is not used for symmetric matrices.
Integer Data File, LUA(4)
Stores all integer pointers necessary to access the file.

The data storage in files LUA(1), LUA(3) and LUA(4) is problem and machine dependent. You should never try and write these files directly.

B.3. FMS Matrix Files

Lower Triangle Data File, LUA(1)

Diagonal Data File, LUA(2)

Upper Triangle Data File, LUA(3)

Integer Data File, LUA(4)