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The next section of the LST file is an equation by equation listing of the solution returned to GAMS by the solver. Each individual equation case is listed. For our three examples the reports are as follows
LOWER LEVEL UPPER MARGINAL
---- EQU OBJ . . . 1.000
---- EQU land -INF 100.000 100.000 52.000
---- EQU labor -INF 500.000 500.000 9.500
LOWER LEVEL UPPER MARGINAL
---- EQU PDemand 6.000 6.000 +INF 10.000
---- EQU PSupply -1.000 -1.000 +INF 10.000
---- EQU Equilibri~ . . +INF 3.000
LOWER LEVEL UPPER MARGINAL
---- EQU r1 1.000 1.000 1.000 0.500
---- EQU r2 4.800 4.800 4.800 EPS
---- EQU r3 0.980 0.980 0.980 4.9951E-6
---- EQU r4 1.000 1.000 1.000 2.3288E-6
---- EQU b1 . . . 0.499
---- EQU b2 . . . 2.5676E-4
The columns associated with each entry have the following meaning,
| • | EQU - Equation identifier |
| • | Lower bound (.lo) – RHS on =G= or =E= equations |
| • | Level value (.l) – value of Left hand side variables. Note this is not a slack variable but inclusion of such information is discussed in the Standard Output chapter. |
| • | Upper bound (.up) – RHS on =L= or =E= equations |
| • | Marginal (.m) – dual variable, shadow price or in MCPs only complementary variable value (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. |
| • | The marginal output generally does not have much meaning in an MCP or CNS model. |
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