[Help-glpk] help! how tow set constraint coeffients to zero?

[CiHang Jin]

Hi all,

I am using GLPK to solve a LP problem, such as:

max            Z = x1 + x2 + x3
subject to:    1 >      x2 + x3
               2 > x1 + x2

In the first row, the coefficient of x1 is zero and in the 2nd line the
coefficient of x3 is zero. I trid to set the constaint matrix by
lpx_load_matrix(),but got an error "lpx_load_matrix: ar[1] = 0; zero element not
allowed".

How could I formulate this problem?

BR!

cihang