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Work Arrays

Many LAPACK routines require one or more work arrays to be passed as arguments. The name of a work array is usually WORK -- sometimes IWORK, RWORK or BWORK to distinguish work arrays of integer, real or logical (Boolean) type.

Occasionally the first element of a work array is used to return some useful information: in such cases, the argument is described as (workspace/output) instead of simply (workspace).

A number of routines implementing block algorithms require workspace sufficient to hold one block of rows or columns of the matrix, for example, workspace of size n-by-nb, where nb is the block size. In such cases, the actual declared length of the work array must be passed as a separate argument LWORK, which immediately follows WORK in the argument-list.

See Section 5.2 for further explanation.