[Help-glpk] the API of GLPK, add_cols problem

[bo liu]

hello everyone,

I have some questions about GLPK through the API.

I have a variable like this :    2<=x<=5   ,through API,  I write it like this:

glp_add_cols(lp,1);

glp_set_col_name(lp,1,"x");

glp_set_col_bnds(lp,1,GLP_LO,2.0,0.0);

glp_set_col_bnds(lp,1,GLP_UP,0.0,5.0);

or like this:

glp_add_cols(lp,2);

glp_set_col_name(lp,1,"x");

glp_set_col_name(lp,2,"x");

glp_set_col_bnds(lp,1,GLP_LO,2.0,0.0);

glp_set_col_bnds(lp,2,GLP_UP,0.0,5.0);

which is right?  

i do not know add 1 cols or add 2 cols .

  thanks very much!

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LEO