Difference between GLP_DUAL and GLP_DUALP in GLPK method

Question

I will really appreciate if any one help me to know the difference between GLP_DUAL and GLP_DUALP in GLPK method.

Answer 1

GLP_DUALP falls back to primal simplex if dual fails, quoting the source:

#define GLP_DUALP          2  /* use dual; if it fails, use primal */
#define GLP_DUAL           3  /* use dual simplex */