Matrix Storage Schemes

LAPACK allows the following different storage schemes for matrices:

• conventional storage in a two-dimensional array;

• packed storage for symmetric, Hermitian or triangular matrices;

• band storage for band matrices;

• the use of two or three one-dimensional arrays to store tridiagonal or bidiagonal matrices.

These storage schemes are compatible with those used in LINPACK and the BLAS, but EISPACK uses incompatible schemes for band and tridiagonal matrices.

In the examples below, $\ast$ indicates an array element that need not be set and is not referenced by LAPACK routines. Elements that ``need not be set'' are never read, written to, or otherwise accessed by the LAPACK routines. The examples illustrate only the relevant part of the arrays; array arguments may of course have additional rows or columns, according to the usual rules for passing array arguments in Fortran 77.