Crystalline compounds (zeolites,sodalites), D. Ronis, Univ. of McGill.

Two matrices from David Ronis, Chemistry Dept, Univ of McGill, Canada.
Email:  ronis :at the domain: onsager.chem.mcgill.ca.

Added to the UF sparse matrix collection on March 19, 2001.

His comments:

    The matrix is generated on the fly in a large code that analyses the
    elastic properties (and many other things) in a class of complicated
    crystalline compounds called zeolites or sodalites.

    Note that in the actual inversions, I add a positive number times the
    unit matrix to this matrix.  The typical value of this scalar is
    anywhere from 1e24 to 1e28--it really doesn't matter from the point of
    view of the calculation I want to do--the matrix is nonsingular in all
    cases.

(in the two matrices, xenon1.rua and xenon2.rua, 1e24 has already been
added to the diagonal).