#  x61.txt
#
#  Discussion:
#
#    This is simply a list of the total system size,
#    and the files that describe the subsystems.
#
#    The first subsystem is a matrix A and right hand side B
#    whose residual norm || A * X - B || is to be minimized.
#
#    The second subsystem is a matrix C and right hand side D
#    which represent constraints, that is, it must be the
#    case that C * X = D exactly.
#
#    The third subsystem is a matrix E and right hand side H
#    which represent positivity constraints, that is, it must be the
#    case that E * X >= H.
#
#    The rank of A is 3, the rank of C is 2.  
#
#    For the L1 problem, the solution is
#
#      ( 0, 1.737705, 0, -0.2377049, -0.1885246 )
#
#    with an L1 error of 26.148.
#
#  Reference:
#
#    I Barrodale and F Roberts,
#    Algorithm 552:
#    Solution of the Constrained L1 Approximation Problem,
#    ACM Transactions on Mathematical Software,
#    Volume 6, Number 2, pages 231-235, 1980.
#
7 columns
13 rows
3 subsystems
x61_01.txt