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The next section of the LST file is a variable by variable listing of the solution returned to GAMS by the solver. Each individual variable case is listed. For our three examples the reports are as follows
LOWER LEVEL UPPER MARGINAL
---- VAR Z -INF 9950.000 +INF .
---- VAR Xcorn . 50.000 +INF .
---- VAR Xwheat . 50.000 +INF .
---- VAR Xcotton . . +INF -13.000
LOWER LEVEL UPPER MARGINAL
---- VAR P . 3.000 +INF .
---- VAR Qd . 10.000 +INF .
---- VAR Qs . 10.000 +INF .
LOWER LEVEL UPPER MARGINAL
---- VAR ba -INF 1.000 +INF .
---- VAR so4 -INF 1.000 +INF .
---- VAR baoh -INF 4.802 +INF .
---- VAR oh -INF 1.000 +INF .
---- VAR hso4 -INF 0.980 +INF .
---- VAR h -INF 1.000 +INF .
The columns associated with each entry have the following meaning,
| • | VAR - Variable identifier |
| • | Lower bound (.lo) – often zero or minus infinity |
| • | Level value (.l) – solution value. |
| • | Upper bound (.up) – often plus infinity |
| • | Margninal (.m) – reduced cost or in MCPs only slack in complementary equations (See the NLP and MCP chapter) |
Notes:
| • | The numbers are printed with fixed precision, but the values are returned within GAMS have full machine accuracy. |
| • | The single dots '.' represent zeros. |
| • | If present EPS is the GAMS extended value that means very close to but different from zero. |
| • | It is common to see a marginal value given as EPS, since GAMS uses the convention that marginals are zero for basic variables, and nonzero for others. |
| • | EPS is used with non-basic variables whose marginal values are very close to, or actually, zero, or in nonlinear problems with superbasic variables whose marginals are zero or very close to it. |
| • | For models that are not solved to optimality, some items may additionally be marked with the following flags. |
| Infes | The item is infeasible. This mark is made for any entry whose level value is not between the upper and lower bounds. |
| Nopt | The item is non-optimal. This mark is made for any non-basic entries for which the marginal sign is incorrect, or superbasic ones for which the marginal value is too large. |
| Unbnd | The row or column that appears to cause the problem to be unbounded. |
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