# 
# Numerical Mathematics and Computing, Fifth Edition
# Ward Cheney & David Kincaid
# Brooks/Cole Publ. Co.
# (c) 2003
#
# file:  gauss_elim1
#
# Solving linear systems
#
# Using package linalg
#
with(linalg):
A := array([[ 6,  -2,   2,   4],
            [12,  -8,   6,  10],
            [ 3, -13,   9,   3],
            [-6,   4,   1, -18]]);
b := array( [16,  26, -19, -34]);
linsolve(A,b);
#
# Using package LinearAlgebra
#
with(LinearAlgebra):
A := Matrix([ [6,-2,2,4],[12,-8,6,10],
              [3,-13,9,3],[-6,4,1,-18]]);
b := Vector([16,26,-19,-34]);
x := LinearSolve(A, b);

with(LinearAlgebra):
Eqns := [ 6*x1  -2*x2 + 2*x3 +  4*x4 =  16,
         12*x1  -8*x2 + 6*x3 + 10*x4 =  26,
          3*x1 -13*x2 + 9*x3 +  3*x4 = -19,
         -6*x1  +4*x2 +   x3 - 18*x4 = -34];
Vars := [x1, x2, x3, x4];
Ab   := GenerateMatrix(Eqns, Vars, augmented=true);
LinearSolve(Ab, method=solve);