From the glpk manual, I copied example E.1 to ex1.gmpl .
glpsol did not like it: [hennebry@fedora triangle-free]$ glpsol --glp ex1.gmpl GLPSOL--GLPK LP/MIP Solver 5.0 Parameter(s) specified in the command line: --glp ex1.gmpl Reading problem data from 'ex1.gmpl'... ex1.gmpl:1: error: problem line missing or invalid GLPK LP/MIP file processing error [hennebry@fedora triangle-free]$
Here is ex1.gmpl: # A TRANSPORTATION PROBLEM # # This problem finds a least cost shipping schedule that meets # requirements at markets and supplies at factories. # # References: # Dantzig G B, "Linear Programming and Extensions." # Princeton University Press, Princeton, New Jersey, 1963, # Chapter 3-3. set I; /* canning plants */ set J; /* markets */ param a{i in I}; /* capacity of plant i in cases */ param b{j in J}; /* demand at market j in cases */ param d{i in I, j in J}; /* distance in thousands of miles */ param f; /* freight in dollars per case per thousand miles */ param c{i in I, j in J} := f * d[i,j] / 1000; /* transport cost in thousands of dollars per case */ var x{i in I, j in J} >= 0; /* shipment quantities in cases */ minimize cost: sum{i in I, j in J} c[i,j] * x[i,j]; /* total transportation costs in thousands of dollars */ s.t. supply{i in I}: sum{j in J} x[i,j] <= a[i]; /* observe supply limit at plant i */ s.t. demand{j in J}: sum{i in I} x[i,j] >= b[j]; /* satisfy demand at market j */ data; set I := Seattle San-Diego; set J := New-York Chicago Topeka; param a := Seattle San-Diego350 600; param b := New-York Chicago Topeka325 300 275; param d :New-York 2.5 2.5 Seattle San-Diego Chicago 1.7 1.8 param f := 90; end; What is going on and what can I do about it? -- Michael henne...@mail.cs.ndsu.nodak.edu "I was just thinking about the life of a pumpkin. Grow up in the sun, happily entwined with others, and then someone comes along, cuts you open, and rips your guts out." -- Buffy