XLAENV sets certain machine- and problem-dependent quantities
 which will later be retrieved by ILAENV.

ISPEC

          ISPEC is INTEGER
          Specifies the parameter to be set in the COMMON array IPARMS.
          = 1: the optimal blocksize; if this value is 1, an unblocked
               algorithm will give the best performance.
          = 2: the minimum block size for which the block routine
               should be used; if the usable block size is less than
               this value, an unblocked routine should be used.
          = 3: the crossover point (in a block routine, for N less
               than this value, an unblocked routine should be used)
          = 4: the number of shifts, used in the nonsymmetric
               eigenvalue routines
          = 5: the minimum column dimension for blocking to be used;
               rectangular blocks must have dimension at least k by m,
               where k is given by ILAENV(2,...) and m by ILAENV(5,...)
          = 6: the crossover point for the SVD (when reducing an m by n
               matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds
               this value, a QR factorization is used first to reduce
               the matrix to a triangular form)
          = 7: the number of processors
          = 8: another crossover point, for the multishift QR and QZ
               methods for nonsymmetric eigenvalue problems.
          = 9: maximum size of the subproblems at the bottom of the
               computation tree in the divide-and-conquer algorithm
               (used by xGELSD and xGESDD)
          =10: ieee NaN arithmetic can be trusted not to trap
          =11: infinity arithmetic can be trusted not to trap

NVALUE

          NVALUE is INTEGER
          The value of the parameter specified by ISPEC.

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