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Member "rlab-2.2.12.2-gcc4.3.2-bin/lib/doc/help/rcond" of archive rlab32-2.2.12.2-gcc4.3.2.bin.tgz:

  rcond
  Builtin Function



      SSyynnooppssiiss
        Condition number.

      SSyynnttaaxx
        rcond( _A )

      DDeessccrriippttiioonn
        Rcond computes an estimate of the condition number of the input
        matrix, _A. rcond() uses the LAPACK routines DGECON, or ZGECON.

        Probably the most published way to compute the condition of a
        matrix is:



          Kcond = ||A|| * ||inv(A)||





     Another method is to use the 1st and last singular values of A:



          Kcond = sigma(1)/sigma(n)





     rcond computes an ESTIMATE of the condition number without
     computing all of the columns of inv(A). For more information see
     the LAPACK User's Guide.

     See Also  inv, det, lu