#  sparsity_input.txt
#
#  Discussion:
#
#    Display the sparsity pattern (location of nonzeros) of a matrix.
#
#    In order for the picture to "look" like a matrix, we have to do
#    some transposition and negation.  In other words, if matrix entry (R,C)
#    is nonzero, then the corresponding entry in the gnuplot file should
#    be (C,-R).  That adjusts for the difference between the matrix (I,J) 
#    and Cartesian (X,Y) coordinates systems 
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    14 October 2013
#
#  Author:
#
#    John Burkardt
#
set term png
#
set output "sparsity_1.png"
set size ratio 1
set title "Initial sparsity pattern"
set xlabel "Column"
set ylabel "Row (ignore minus sign)"
set timestamp
plot "sparsity_1_data.txt"
#
set output "sparsity_2.png"
set size ratio 1
set title "Sparsity pattern after reordering"
set xlabel "Column"
set ylabel "Row (ignore minus sign)"
set timestamp
plot "sparsity_2_data.txt"
#
quit