# 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