The array descriptor DESC_
whose type is defined as
DESC_(DTYPE_)=601 ,
is an integer array of length 11.
DESC_(DTYPE_)=601
is used for the ScaLAPACK routines
involved in the out-of-core solution
of dense linear systems using LU, QR
or Cholesky factorizations [55].
The matrix stored on disk is composed
of records each record of which corresponds
to an MMB NNB DESC_(DTYPE_)=1
ScaLAPACK matrix and these records
are organized in a column major
(Fortran array) manner. The array
descriptor for out-of-core matrices
has extra fields to store file
parameters associated with the
matrix, such as the I/O device
unit number, MMB and NNB, and
the amount of temporary buffer
storage available.
Similar to DESC_(DTYPE_)=1 symmetric ScaLAPACK matrices, only the upper (UPLO='U') triangle or the lower (UPLO='L') triangle is accessed. The entire coefficient matrix is stored on disk, regardless of whether the matrix is nonsymmetric or symmetric.
Table 4.13: Content of the array descriptor for out-of-core dense matrices