cplex python sum constraint -

i started cplex python api , got problem creating linear_constraints model

i want that:

dvar float+ x[]  minimize:  sum(i in i) c[i] * x[i]  subject to: sum(i in i) x[i] <= constantvalue 

and problem dont know how make constraint in python api

  cpx.linear_constraints.add(             lin_expr=  1,             senses=["l"],             rhs=constantvalue,             range_values= 2, 

what want ask u need type in 1) , 2) sum of x[i] table need decision variable.

here example:

>>> import cplex >>> c = cplex.cplex() >>> c.variables.add(names = ["x1", "x2", "x3"]) >>> c.linear_constraints.add(lin_expr = [cplex.sparsepair(ind = ["x1", "x3"], val = [1.0, -1.0]),                                  cplex.sparsepair(ind = ["x1", "x2"], val = [1.0, 1.0]),                                  cplex.sparsepair(ind = ["x1", "x2", "x3"], val = [-1.0] * 3),                                  cplex.sparsepair(ind = ["x2", "x3"], val = [10.0, -2.0])],                          senses = ["e", "l", "g", "r"],                          rhs = [0.0, 1.0, -1.0, 2.0],                          range_values = [0.0, 0.0, 0.0, -10.0],                          names = ["c0", "c1", "c2", "c3"],) >>> c.linear_constraints.get_rhs() [0.0, 1.0, -1.0, 2.0] 

where range_values list of floats, specifying difference between lefthand side , righthand side of each linear constraint. if range_values[i] > 0 (zero) constraint defined rhs[i] <= rhs[i] + range_values[i]. if range_values[i] < 0 (zero) constraint defined rhs[i] + range_value[i] <= a*x <= rhs[i]. suggest leave default value (blank).

to define sum indicate variables , vector of ones, e.g.,

numcols = 10 vars = [ 'x'+str(n) n in xrange(1,numcols+1) ] coef = [1]*numcols cpx.linear_constraints.add(         lin_expr= [cplex.sparsepair(ind = vars, val = coef)] ,         senses=["l"],         rhs=[constantvalue] )