Other Features

Miscellaneous Functions

• basic_vector(T) returns the vector in which the nonbasic variables have been set to zero.
• get_Abc(T) returns the original matrix A and the vectors b and c for the standard presentation of the linear program.
• get_basis(T) returns the column numbers of the current basis.
• is_feasible(T) returns true if the current basic vector is in the feasible region.
• is_optimal(T) returns true if the tableau has reached an optimal (minimal) state.
• value(T) returns the objective function value of the current basic vector.

Return to Start

The function restore! returns the tableau to its state when it was constructed.

julia> T
┌──────────┬───┬─────┬─────┬────────┬─────┬─────────┬──────────┐
│          │ z │ x_1 │ x_2 │    x_3 │ x_4 │     x_5 │      RHS │
│ Obj Func │ 1 │   0 │   0 │ -25/47 │   0 │ -110/47 │ 13500/47 │
├──────────┼───┼─────┼─────┼────────┼─────┼─────────┼──────────┤
│   Cons 1 │ 0 │   1 │   0 │   1/47 │   0 │   -5/47 │   400/47 │
│   Cons 2 │ 0 │   0 │   0 │ -25/47 │   1 │  -16/47 │  -600/47 │
│   Cons 3 │ 0 │   0 │   1 │  -5/47 │   0 │    3/94 │   350/47 │
└──────────┴───┴─────┴─────┴────────┴─────┴─────────┴──────────┘


julia> restore!(T)
┌──────────┬───┬─────┬─────┬─────┬─────┬─────┬─────┐
│          │ z │ x_1 │ x_2 │ x_3 │ x_4 │ x_5 │ RHS │
│ Obj Func │ 1 │ -25 │ -10 │   0 │   0 │   0 │   0 │
├──────────┼───┼─────┼─────┼─────┼─────┼─────┼─────┤
│   Cons 1 │ 0 │   3 │  10 │  -1 │   0 │   0 │ 100 │
│   Cons 2 │ 0 │   5 │   6 │   0 │  -1 │   0 │ 100 │
│   Cons 3 │ 0 │  10 │   2 │   0 │   0 │  -1 │ 100 │
└──────────┴───┴─────┴─────┴─────┴─────┴─────┴─────┘

LaTeX Output

Using LatexPrint users can get the code for pasting into a LaTeX document.

julia> using LatexPrint

julia> T
┌──────────┬───┬─────┬─────┬─────┬─────┬──────┬─────┐
│          │ z │ x_1 │ x_2 │ x_3 │ x_4 │  x_5 │ RHS │
│ Obj Func │ 1 │   0 │  -3 │  -2 │   8 │    0 │   9 │
├──────────┼───┼─────┼─────┼─────┼─────┼──────┼─────┤
│   Cons 1 │ 0 │   1 │ 1/2 │   0 │ 9/2 │ -1/2 │ 9/2 │
│   Cons 2 │ 0 │   0 │ 1/2 │  -1 │ 1/2 │  3/2 │ 5/2 │
└──────────┴───┴─────┴─────┴─────┴─────┴──────┴─────┘


julia> lap(T)
\begin{tabular}{|c|ccccc|c|}\hline 
{\Large\strut}$z$ &$x_{1}$ & $x_{2}$ & $x_{3}$ & $x_{4}$ & $x_{5}$ & RHS \\
{\Large\strut}$1$ & $0$ & $-3$ & $-2$ & $8$ & $0$ & $9$\\
\hline 
{\Large\strut}$0$ & $1$ & $\frac{1}{2}$ & $0$ & $\frac{9}{2}$ & $\frac{-1}{2}$ & $\frac{9}{2}$\\
{\Large\strut}$0$ & $0$ & $\frac{1}{2}$ & $-1$ & $\frac{1}{2}$ & $\frac{3}{2}$ & $\frac{5}{2}$\\
\hline 
\end{tabular}

Here is the LaTeX output:

Other Public Functions

Presently, these functions are exported in SimplexTableaux but might be hidden in future releases. They are not likely to be useful to the users of this module. See the doc strings for more information:

• big_M_tableau
• check_basis
• find_pivot_column
• infer_basis!