Example program for dpttrs

This example solves the equations
AX=B ,  
where A  is the symmetric positive definite tridiagonal matrix
A = 4.0 -2.0 0.0 0.0 0.0 -2.0 10.0 -6.0 0.0 0.0 0.0 -6.0 29.0 15.0 0.0 0.0 0.0 15.0 25.0 8.0 0.0 0.0 0.0 8.0 5.0   and   B = 6.0 10.0 9.0 4.0 2.0 9.0 14.0 65.0 7.0 23.0 .