Unequal constraints

[limeng12]

Hi,

I'm experiencing the following problems when using this software.

Error in lpsymphony_solve_LP(obj = f.obj, mat = f.con, dir = f.dir, rhs = f.rhs, : Argument 'dir' must be one of '<', '<=', '>', '>=', or '=='.

But the help document showed that this software supports unequal operation !=.

Arguments  |

obj | a vector with the objective coefficients
mat | a vector or a matrix of the constraint coefficients
dir | a character vector with the directions of the constraints. Each element must be one of "<", "<=", ">", ">=", "==" or "!=".

Meng