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- """
- Created on Sat Aug 22 19:49:17 2020
- @author: matth
- """
- def _linprog_highs_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='highs', callback=None,
- maxiter=None, disp=False, presolve=True,
- time_limit=None,
- dual_feasibility_tolerance=None,
- primal_feasibility_tolerance=None,
- ipm_optimality_tolerance=None,
- simplex_dual_edge_weight_strategy=None,
- mip_rel_gap=None,
- **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using one of the HiGHS solvers.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'highs', which chooses
- automatically between
- :ref:`'highs-ds' <optimize.linprog-highs-ds>` and
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy)
- are also available.
- integrality : 1-D array or int, optional
- Indicates the type of integrality constraint on each decision variable.
- ``0`` : Continuous variable; no integrality constraint.
- ``1`` : Integer variable; decision variable must be an integer
- within `bounds`.
- ``2`` : Semi-continuous variable; decision variable must be within
- `bounds` or take value ``0``.
- ``3`` : Semi-integer variable; decision variable must be an integer
- within `bounds` or take value ``0``.
- By default, all variables are continuous.
- For mixed integrality constraints, supply an array of shape `c.shape`.
- To infer a constraint on each decision variable from shorter inputs,
- the argument will be broadcast to `c.shape` using `np.broadcast_to`.
- This argument is currently used only by the ``'highs'`` method and
- ignored otherwise.
- Options
- -------
- maxiter : int
- The maximum number of iterations to perform in either phase.
- For :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`, this does not
- include the number of crossover iterations. Default is the largest
- possible value for an ``int`` on the platform.
- disp : bool (default: ``False``)
- Set to ``True`` if indicators of optimization status are to be
- printed to the console during optimization.
- presolve : bool (default: ``True``)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- time_limit : float
- The maximum time in seconds allotted to solve the problem;
- default is the largest possible value for a ``double`` on the
- platform.
- dual_feasibility_tolerance : double (default: 1e-07)
- Dual feasibility tolerance for
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`.
- The minimum of this and ``primal_feasibility_tolerance``
- is used for the feasibility tolerance of
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- primal_feasibility_tolerance : double (default: 1e-07)
- Primal feasibility tolerance for
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`.
- The minimum of this and ``dual_feasibility_tolerance``
- is used for the feasibility tolerance of
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- ipm_optimality_tolerance : double (default: ``1e-08``)
- Optimality tolerance for
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- Minimum allowable value is 1e-12.
- simplex_dual_edge_weight_strategy : str (default: None)
- Strategy for simplex dual edge weights. The default, ``None``,
- automatically selects one of the following.
- ``'dantzig'`` uses Dantzig's original strategy of choosing the most
- negative reduced cost.
- ``'devex'`` uses the strategy described in [15]_.
- ``steepest`` uses the exact steepest edge strategy as described in
- [16]_.
- ``'steepest-devex'`` begins with the exact steepest edge strategy
- until the computation is too costly or inexact and then switches to
- the devex method.
- Currently, ``None`` always selects ``'steepest-devex'``, but this
- may change as new options become available.
- mip_rel_gap : double (default: None)
- Termination criterion for MIP solver: solver will terminate when the
- gap between the primal objective value and the dual objective bound,
- scaled by the primal objective value, is <= mip_rel_gap.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- ``unknown_options`` is non-empty, a warning is issued listing
- all unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1D array
- The (nominally positive) values of the slack,
- ``b_ub - A_ub @ x``.
- con : 1D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration or time limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : The HiGHS solver ran into a problem.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed.
- For the HiGHS simplex method, this includes iterations in all
- phases. For the HiGHS interior-point method, this does not include
- crossover iterations.
- crossover_nit : int
- The number of primal/dual pushes performed during the
- crossover routine for the HiGHS interior-point method.
- This is ``0`` for the HiGHS simplex method.
- ineqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- inequality constraints, `b_ub`. A dictionary consisting of the
- fields:
- residual : np.ndnarray
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``. This quantity is also commonly
- referred to as "slack".
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- inequality constraints, `b_ub`.
- eqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- equality constraints, `b_eq`. A dictionary consisting of the
- fields:
- residual : np.ndarray
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- equality constraints, `b_eq`.
- lower, upper : OptimizeResult
- Solution and sensitivity information corresponding to the
- lower and upper bounds on decision variables, `bounds`.
- residual : np.ndarray
- The (nominally positive) values of the quantity
- ``x - lb`` (lower) or ``ub - x`` (upper).
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the lower and upper
- `bounds`.
- Notes
- -----
- Method :ref:`'highs-ds' <optimize.linprog-highs-ds>` is a wrapper
- of the C++ high performance dual revised simplex implementation (HSOL)
- [13]_, [14]_. Method :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`
- is a wrapper of a C++ implementation of an **i**\ nterior-\ **p**\ oint
- **m**\ ethod [13]_; it features a crossover routine, so it is as accurate
- as a simplex solver. Method :ref:`'highs' <optimize.linprog-highs>` chooses
- between the two automatically. For new code involving `linprog`, we
- recommend explicitly choosing one of these three method values instead of
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy).
- The result fields `ineqlin`, `eqlin`, `lower`, and `upper` all contain
- `marginals`, or partial derivatives of the objective function with respect
- to the right-hand side of each constraint. These partial derivatives are
- also referred to as "Lagrange multipliers", "dual values", and
- "shadow prices". The sign convention of `marginals` is opposite that
- of Lagrange multipliers produced by many nonlinear solvers.
- References
- ----------
- .. [13] Huangfu, Q., Galabova, I., Feldmeier, M., and Hall, J. A. J.
- "HiGHS - high performance software for linear optimization."
- https://highs.dev/
- .. [14] Huangfu, Q. and Hall, J. A. J. "Parallelizing the dual revised
- simplex method." Mathematical Programming Computation, 10 (1),
- 119-142, 2018. DOI: 10.1007/s12532-017-0130-5
- .. [15] Harris, Paula MJ. "Pivot selection methods of the Devex LP code."
- Mathematical programming 5.1 (1973): 1-28.
- .. [16] Goldfarb, Donald, and John Ker Reid. "A practicable steepest-edge
- simplex algorithm." Mathematical Programming 12.1 (1977): 361-371.
- """
- pass
- def _linprog_highs_ds_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='highs-ds', callback=None,
- maxiter=None, disp=False, presolve=True,
- time_limit=None,
- dual_feasibility_tolerance=None,
- primal_feasibility_tolerance=None,
- simplex_dual_edge_weight_strategy=None,
- **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using the HiGHS dual simplex solver.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'highs-ds'.
- :ref:`'highs' <optimize.linprog-highs>`,
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`,
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy)
- are also available.
- Options
- -------
- maxiter : int
- The maximum number of iterations to perform in either phase.
- Default is the largest possible value for an ``int`` on the platform.
- disp : bool (default: ``False``)
- Set to ``True`` if indicators of optimization status are to be
- printed to the console during optimization.
- presolve : bool (default: ``True``)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- time_limit : float
- The maximum time in seconds allotted to solve the problem;
- default is the largest possible value for a ``double`` on the
- platform.
- dual_feasibility_tolerance : double (default: 1e-07)
- Dual feasibility tolerance for
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`.
- primal_feasibility_tolerance : double (default: 1e-07)
- Primal feasibility tolerance for
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`.
- simplex_dual_edge_weight_strategy : str (default: None)
- Strategy for simplex dual edge weights. The default, ``None``,
- automatically selects one of the following.
- ``'dantzig'`` uses Dantzig's original strategy of choosing the most
- negative reduced cost.
- ``'devex'`` uses the strategy described in [15]_.
- ``steepest`` uses the exact steepest edge strategy as described in
- [16]_.
- ``'steepest-devex'`` begins with the exact steepest edge strategy
- until the computation is too costly or inexact and then switches to
- the devex method.
- Currently, ``None`` always selects ``'steepest-devex'``, but this
- may change as new options become available.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- ``unknown_options`` is non-empty, a warning is issued listing
- all unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1D array
- The (nominally positive) values of the slack,
- ``b_ub - A_ub @ x``.
- con : 1D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration or time limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : The HiGHS solver ran into a problem.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed. This includes iterations
- in all phases.
- crossover_nit : int
- This is always ``0`` for the HiGHS simplex method.
- For the HiGHS interior-point method, this is the number of
- primal/dual pushes performed during the crossover routine.
- ineqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- inequality constraints, `b_ub`. A dictionary consisting of the
- fields:
- residual : np.ndnarray
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``. This quantity is also commonly
- referred to as "slack".
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- inequality constraints, `b_ub`.
- eqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- equality constraints, `b_eq`. A dictionary consisting of the
- fields:
- residual : np.ndarray
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- equality constraints, `b_eq`.
- lower, upper : OptimizeResult
- Solution and sensitivity information corresponding to the
- lower and upper bounds on decision variables, `bounds`.
- residual : np.ndarray
- The (nominally positive) values of the quantity
- ``x - lb`` (lower) or ``ub - x`` (upper).
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the lower and upper
- `bounds`.
- Notes
- -----
- Method :ref:`'highs-ds' <optimize.linprog-highs-ds>` is a wrapper
- of the C++ high performance dual revised simplex implementation (HSOL)
- [13]_, [14]_. Method :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`
- is a wrapper of a C++ implementation of an **i**\ nterior-\ **p**\ oint
- **m**\ ethod [13]_; it features a crossover routine, so it is as accurate
- as a simplex solver. Method :ref:`'highs' <optimize.linprog-highs>` chooses
- between the two automatically. For new code involving `linprog`, we
- recommend explicitly choosing one of these three method values instead of
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy).
- The result fields `ineqlin`, `eqlin`, `lower`, and `upper` all contain
- `marginals`, or partial derivatives of the objective function with respect
- to the right-hand side of each constraint. These partial derivatives are
- also referred to as "Lagrange multipliers", "dual values", and
- "shadow prices". The sign convention of `marginals` is opposite that
- of Lagrange multipliers produced by many nonlinear solvers.
- References
- ----------
- .. [13] Huangfu, Q., Galabova, I., Feldmeier, M., and Hall, J. A. J.
- "HiGHS - high performance software for linear optimization."
- https://highs.dev/
- .. [14] Huangfu, Q. and Hall, J. A. J. "Parallelizing the dual revised
- simplex method." Mathematical Programming Computation, 10 (1),
- 119-142, 2018. DOI: 10.1007/s12532-017-0130-5
- .. [15] Harris, Paula MJ. "Pivot selection methods of the Devex LP code."
- Mathematical programming 5.1 (1973): 1-28.
- .. [16] Goldfarb, Donald, and John Ker Reid. "A practicable steepest-edge
- simplex algorithm." Mathematical Programming 12.1 (1977): 361-371.
- """
- pass
- def _linprog_highs_ipm_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='highs-ipm', callback=None,
- maxiter=None, disp=False, presolve=True,
- time_limit=None,
- dual_feasibility_tolerance=None,
- primal_feasibility_tolerance=None,
- ipm_optimality_tolerance=None,
- **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using the HiGHS interior point solver.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'highs-ipm'.
- :ref:`'highs-ipm' <optimize.linprog-highs>`,
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`,
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy)
- are also available.
- Options
- -------
- maxiter : int
- The maximum number of iterations to perform in either phase.
- For :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`, this does not
- include the number of crossover iterations. Default is the largest
- possible value for an ``int`` on the platform.
- disp : bool (default: ``False``)
- Set to ``True`` if indicators of optimization status are to be
- printed to the console during optimization.
- presolve : bool (default: ``True``)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- time_limit : float
- The maximum time in seconds allotted to solve the problem;
- default is the largest possible value for a ``double`` on the
- platform.
- dual_feasibility_tolerance : double (default: 1e-07)
- The minimum of this and ``primal_feasibility_tolerance``
- is used for the feasibility tolerance of
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- primal_feasibility_tolerance : double (default: 1e-07)
- The minimum of this and ``dual_feasibility_tolerance``
- is used for the feasibility tolerance of
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- ipm_optimality_tolerance : double (default: ``1e-08``)
- Optimality tolerance for
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`.
- Minimum allowable value is 1e-12.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- ``unknown_options`` is non-empty, a warning is issued listing
- all unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1D array
- The (nominally positive) values of the slack,
- ``b_ub - A_ub @ x``.
- con : 1D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration or time limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : The HiGHS solver ran into a problem.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed.
- For the HiGHS interior-point method, this does not include
- crossover iterations.
- crossover_nit : int
- The number of primal/dual pushes performed during the
- crossover routine for the HiGHS interior-point method.
- ineqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- inequality constraints, `b_ub`. A dictionary consisting of the
- fields:
- residual : np.ndnarray
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``. This quantity is also commonly
- referred to as "slack".
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- inequality constraints, `b_ub`.
- eqlin : OptimizeResult
- Solution and sensitivity information corresponding to the
- equality constraints, `b_eq`. A dictionary consisting of the
- fields:
- residual : np.ndarray
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the right-hand side of the
- equality constraints, `b_eq`.
- lower, upper : OptimizeResult
- Solution and sensitivity information corresponding to the
- lower and upper bounds on decision variables, `bounds`.
- residual : np.ndarray
- The (nominally positive) values of the quantity
- ``x - lb`` (lower) or ``ub - x`` (upper).
- marginals : np.ndarray
- The sensitivity (partial derivative) of the objective
- function with respect to the lower and upper
- `bounds`.
- Notes
- -----
- Method :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`
- is a wrapper of a C++ implementation of an **i**\ nterior-\ **p**\ oint
- **m**\ ethod [13]_; it features a crossover routine, so it is as accurate
- as a simplex solver.
- Method :ref:`'highs-ds' <optimize.linprog-highs-ds>` is a wrapper
- of the C++ high performance dual revised simplex implementation (HSOL)
- [13]_, [14]_. Method :ref:`'highs' <optimize.linprog-highs>` chooses
- between the two automatically. For new code involving `linprog`, we
- recommend explicitly choosing one of these three method values instead of
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy).
- The result fields `ineqlin`, `eqlin`, `lower`, and `upper` all contain
- `marginals`, or partial derivatives of the objective function with respect
- to the right-hand side of each constraint. These partial derivatives are
- also referred to as "Lagrange multipliers", "dual values", and
- "shadow prices". The sign convention of `marginals` is opposite that
- of Lagrange multipliers produced by many nonlinear solvers.
- References
- ----------
- .. [13] Huangfu, Q., Galabova, I., Feldmeier, M., and Hall, J. A. J.
- "HiGHS - high performance software for linear optimization."
- https://highs.dev/
- .. [14] Huangfu, Q. and Hall, J. A. J. "Parallelizing the dual revised
- simplex method." Mathematical Programming Computation, 10 (1),
- 119-142, 2018. DOI: 10.1007/s12532-017-0130-5
- """
- pass
- def _linprog_ip_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='interior-point', callback=None,
- maxiter=1000, disp=False, presolve=True,
- tol=1e-8, autoscale=False, rr=True,
- alpha0=.99995, beta=0.1, sparse=False,
- lstsq=False, sym_pos=True, cholesky=True, pc=True,
- ip=False, permc_spec='MMD_AT_PLUS_A', **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using the interior-point method of
- [4]_.
- .. deprecated:: 1.9.0
- `method='interior-point'` will be removed in SciPy 1.11.0.
- It is replaced by `method='highs'` because the latter is
- faster and more robust.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'interior-point'.
- :ref:`'highs' <optimize.linprog-highs>`,
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`,
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`,
- :ref:`'revised simplex' <optimize.linprog-revised_simplex>`, and
- :ref:`'simplex' <optimize.linprog-simplex>` (legacy)
- are also available.
- callback : callable, optional
- Callback function to be executed once per iteration.
- Options
- -------
- maxiter : int (default: 1000)
- The maximum number of iterations of the algorithm.
- disp : bool (default: False)
- Set to ``True`` if indicators of optimization status are to be printed
- to the console each iteration.
- presolve : bool (default: True)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- tol : float (default: 1e-8)
- Termination tolerance to be used for all termination criteria;
- see [4]_ Section 4.5.
- autoscale : bool (default: False)
- Set to ``True`` to automatically perform equilibration.
- Consider using this option if the numerical values in the
- constraints are separated by several orders of magnitude.
- rr : bool (default: True)
- Set to ``False`` to disable automatic redundancy removal.
- alpha0 : float (default: 0.99995)
- The maximal step size for Mehrota's predictor-corrector search
- direction; see :math:`\beta_{3}` of [4]_ Table 8.1.
- beta : float (default: 0.1)
- The desired reduction of the path parameter :math:`\mu` (see [6]_)
- when Mehrota's predictor-corrector is not in use (uncommon).
- sparse : bool (default: False)
- Set to ``True`` if the problem is to be treated as sparse after
- presolve. If either ``A_eq`` or ``A_ub`` is sparse,
- this option will automatically be set ``True``, and the problem
- will be treated as sparse even during presolve. If your constraint
- matrices contain mostly zeros and the problem is not very small (less
- than about 100 constraints or variables), consider setting ``True``
- or providing ``A_eq`` and ``A_ub`` as sparse arrays.
- lstsq : bool (default: ``False``)
- Set to ``True`` if the problem is expected to be very poorly
- conditioned. This should always be left ``False`` unless severe
- numerical difficulties are encountered. Leave this at the default
- unless you receive a warning message suggesting otherwise.
- sym_pos : bool (default: True)
- Leave ``True`` if the problem is expected to yield a well conditioned
- symmetric positive definite normal equation matrix
- (almost always). Leave this at the default unless you receive
- a warning message suggesting otherwise.
- cholesky : bool (default: True)
- Set to ``True`` if the normal equations are to be solved by explicit
- Cholesky decomposition followed by explicit forward/backward
- substitution. This is typically faster for problems
- that are numerically well-behaved.
- pc : bool (default: True)
- Leave ``True`` if the predictor-corrector method of Mehrota is to be
- used. This is almost always (if not always) beneficial.
- ip : bool (default: False)
- Set to ``True`` if the improved initial point suggestion due to [4]_
- Section 4.3 is desired. Whether this is beneficial or not
- depends on the problem.
- permc_spec : str (default: 'MMD_AT_PLUS_A')
- (Has effect only with ``sparse = True``, ``lstsq = False``, ``sym_pos =
- True``, and no SuiteSparse.)
- A matrix is factorized in each iteration of the algorithm.
- This option specifies how to permute the columns of the matrix for
- sparsity preservation. Acceptable values are:
- - ``NATURAL``: natural ordering.
- - ``MMD_ATA``: minimum degree ordering on the structure of A^T A.
- - ``MMD_AT_PLUS_A``: minimum degree ordering on the structure of A^T+A.
- - ``COLAMD``: approximate minimum degree column ordering.
- This option can impact the convergence of the
- interior point algorithm; test different values to determine which
- performs best for your problem. For more information, refer to
- ``scipy.sparse.linalg.splu``.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- `unknown_options` is non-empty a warning is issued listing all
- unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1-D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1-D array
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``.
- con : 1-D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : Numerical difficulties encountered.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed in all phases.
- Notes
- -----
- This method implements the algorithm outlined in [4]_ with ideas from [8]_
- and a structure inspired by the simpler methods of [6]_.
- The primal-dual path following method begins with initial 'guesses' of
- the primal and dual variables of the standard form problem and iteratively
- attempts to solve the (nonlinear) Karush-Kuhn-Tucker conditions for the
- problem with a gradually reduced logarithmic barrier term added to the
- objective. This particular implementation uses a homogeneous self-dual
- formulation, which provides certificates of infeasibility or unboundedness
- where applicable.
- The default initial point for the primal and dual variables is that
- defined in [4]_ Section 4.4 Equation 8.22. Optionally (by setting initial
- point option ``ip=True``), an alternate (potentially improved) starting
- point can be calculated according to the additional recommendations of
- [4]_ Section 4.4.
- A search direction is calculated using the predictor-corrector method
- (single correction) proposed by Mehrota and detailed in [4]_ Section 4.1.
- (A potential improvement would be to implement the method of multiple
- corrections described in [4]_ Section 4.2.) In practice, this is
- accomplished by solving the normal equations, [4]_ Section 5.1 Equations
- 8.31 and 8.32, derived from the Newton equations [4]_ Section 5 Equations
- 8.25 (compare to [4]_ Section 4 Equations 8.6-8.8). The advantage of
- solving the normal equations rather than 8.25 directly is that the
- matrices involved are symmetric positive definite, so Cholesky
- decomposition can be used rather than the more expensive LU factorization.
- With default options, the solver used to perform the factorization depends
- on third-party software availability and the conditioning of the problem.
- For dense problems, solvers are tried in the following order:
- 1. ``scipy.linalg.cho_factor``
- 2. ``scipy.linalg.solve`` with option ``sym_pos=True``
- 3. ``scipy.linalg.solve`` with option ``sym_pos=False``
- 4. ``scipy.linalg.lstsq``
- For sparse problems:
- 1. ``sksparse.cholmod.cholesky`` (if scikit-sparse and SuiteSparse are
- installed)
- 2. ``scipy.sparse.linalg.factorized`` (if scikit-umfpack and SuiteSparse
- are installed)
- 3. ``scipy.sparse.linalg.splu`` (which uses SuperLU distributed with SciPy)
- 4. ``scipy.sparse.linalg.lsqr``
- If the solver fails for any reason, successively more robust (but slower)
- solvers are attempted in the order indicated. Attempting, failing, and
- re-starting factorization can be time consuming, so if the problem is
- numerically challenging, options can be set to bypass solvers that are
- failing. Setting ``cholesky=False`` skips to solver 2,
- ``sym_pos=False`` skips to solver 3, and ``lstsq=True`` skips
- to solver 4 for both sparse and dense problems.
- Potential improvements for combating issues associated with dense
- columns in otherwise sparse problems are outlined in [4]_ Section 5.3 and
- [10]_ Section 4.1-4.2; the latter also discusses the alleviation of
- accuracy issues associated with the substitution approach to free
- variables.
- After calculating the search direction, the maximum possible step size
- that does not activate the non-negativity constraints is calculated, and
- the smaller of this step size and unity is applied (as in [4]_ Section
- 4.1.) [4]_ Section 4.3 suggests improvements for choosing the step size.
- The new point is tested according to the termination conditions of [4]_
- Section 4.5. The same tolerance, which can be set using the ``tol`` option,
- is used for all checks. (A potential improvement would be to expose
- the different tolerances to be set independently.) If optimality,
- unboundedness, or infeasibility is detected, the solve procedure
- terminates; otherwise it repeats.
- Whereas the top level ``linprog`` module expects a problem of form:
- Minimize::
- c @ x
- Subject to::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- where ``lb = 0`` and ``ub = None`` unless set in ``bounds``. The problem
- is automatically converted to the form:
- Minimize::
- c @ x
- Subject to::
- A @ x == b
- x >= 0
- for solution. That is, the original problem contains equality, upper-bound
- and variable constraints whereas the method specific solver requires
- equality constraints and variable non-negativity. ``linprog`` converts the
- original problem to standard form by converting the simple bounds to upper
- bound constraints, introducing non-negative slack variables for inequality
- constraints, and expressing unbounded variables as the difference between
- two non-negative variables. The problem is converted back to the original
- form before results are reported.
- References
- ----------
- .. [4] Andersen, Erling D., and Knud D. Andersen. "The MOSEK interior point
- optimizer for linear programming: an implementation of the
- homogeneous algorithm." High performance optimization. Springer US,
- 2000. 197-232.
- .. [6] Freund, Robert M. "Primal-Dual Interior-Point Methods for Linear
- Programming based on Newton's Method." Unpublished Course Notes,
- March 2004. Available 2/25/2017 at
- https://ocw.mit.edu/courses/sloan-school-of-management/15-084j-nonlinear-programming-spring-2004/lecture-notes/lec14_int_pt_mthd.pdf
- .. [8] Andersen, Erling D., and Knud D. Andersen. "Presolving in linear
- programming." Mathematical Programming 71.2 (1995): 221-245.
- .. [9] Bertsimas, Dimitris, and J. Tsitsiklis. "Introduction to linear
- programming." Athena Scientific 1 (1997): 997.
- .. [10] Andersen, Erling D., et al. Implementation of interior point
- methods for large scale linear programming. HEC/Universite de
- Geneve, 1996.
- """
- pass
- def _linprog_rs_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='interior-point', callback=None,
- x0=None, maxiter=5000, disp=False, presolve=True,
- tol=1e-12, autoscale=False, rr=True, maxupdate=10,
- mast=False, pivot="mrc", **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using the revised simplex method.
- .. deprecated:: 1.9.0
- `method='revised simplex'` will be removed in SciPy 1.11.0.
- It is replaced by `method='highs'` because the latter is
- faster and more robust.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'revised simplex'.
- :ref:`'highs' <optimize.linprog-highs>`,
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`,
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`,
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- and :ref:`'simplex' <optimize.linprog-simplex>` (legacy)
- are also available.
- callback : callable, optional
- Callback function to be executed once per iteration.
- x0 : 1-D array, optional
- Guess values of the decision variables, which will be refined by
- the optimization algorithm. This argument is currently used only by the
- 'revised simplex' method, and can only be used if `x0` represents a
- basic feasible solution.
- Options
- -------
- maxiter : int (default: 5000)
- The maximum number of iterations to perform in either phase.
- disp : bool (default: False)
- Set to ``True`` if indicators of optimization status are to be printed
- to the console each iteration.
- presolve : bool (default: True)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- tol : float (default: 1e-12)
- The tolerance which determines when a solution is "close enough" to
- zero in Phase 1 to be considered a basic feasible solution or close
- enough to positive to serve as an optimal solution.
- autoscale : bool (default: False)
- Set to ``True`` to automatically perform equilibration.
- Consider using this option if the numerical values in the
- constraints are separated by several orders of magnitude.
- rr : bool (default: True)
- Set to ``False`` to disable automatic redundancy removal.
- maxupdate : int (default: 10)
- The maximum number of updates performed on the LU factorization.
- After this many updates is reached, the basis matrix is factorized
- from scratch.
- mast : bool (default: False)
- Minimize Amortized Solve Time. If enabled, the average time to solve
- a linear system using the basis factorization is measured. Typically,
- the average solve time will decrease with each successive solve after
- initial factorization, as factorization takes much more time than the
- solve operation (and updates). Eventually, however, the updated
- factorization becomes sufficiently complex that the average solve time
- begins to increase. When this is detected, the basis is refactorized
- from scratch. Enable this option to maximize speed at the risk of
- nondeterministic behavior. Ignored if ``maxupdate`` is 0.
- pivot : "mrc" or "bland" (default: "mrc")
- Pivot rule: Minimum Reduced Cost ("mrc") or Bland's rule ("bland").
- Choose Bland's rule if iteration limit is reached and cycling is
- suspected.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- `unknown_options` is non-empty a warning is issued listing all
- unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1-D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1-D array
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``.
- con : 1-D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : Numerical difficulties encountered.
- ``5`` : Problem has no constraints; turn presolve on.
- ``6`` : Invalid guess provided.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed in all phases.
- Notes
- -----
- Method *revised simplex* uses the revised simplex method as described in
- [9]_, except that a factorization [11]_ of the basis matrix, rather than
- its inverse, is efficiently maintained and used to solve the linear systems
- at each iteration of the algorithm.
- References
- ----------
- .. [9] Bertsimas, Dimitris, and J. Tsitsiklis. "Introduction to linear
- programming." Athena Scientific 1 (1997): 997.
- .. [11] Bartels, Richard H. "A stabilization of the simplex method."
- Journal in Numerische Mathematik 16.5 (1971): 414-434.
- """
- pass
- def _linprog_simplex_doc(c, A_ub=None, b_ub=None, A_eq=None, b_eq=None,
- bounds=None, method='interior-point', callback=None,
- maxiter=5000, disp=False, presolve=True,
- tol=1e-12, autoscale=False, rr=True, bland=False,
- **unknown_options):
- r"""
- Linear programming: minimize a linear objective function subject to linear
- equality and inequality constraints using the tableau-based simplex method.
- .. deprecated:: 1.9.0
- `method='simplex'` will be removed in SciPy 1.11.0.
- It is replaced by `method='highs'` because the latter is
- faster and more robust.
- Linear programming solves problems of the following form:
- .. math::
- \min_x \ & c^T x \\
- \mbox{such that} \ & A_{ub} x \leq b_{ub},\\
- & A_{eq} x = b_{eq},\\
- & l \leq x \leq u ,
- where :math:`x` is a vector of decision variables; :math:`c`,
- :math:`b_{ub}`, :math:`b_{eq}`, :math:`l`, and :math:`u` are vectors; and
- :math:`A_{ub}` and :math:`A_{eq}` are matrices.
- Alternatively, that's:
- minimize::
- c @ x
- such that::
- A_ub @ x <= b_ub
- A_eq @ x == b_eq
- lb <= x <= ub
- Note that by default ``lb = 0`` and ``ub = None`` unless specified with
- ``bounds``.
- Parameters
- ----------
- c : 1-D array
- The coefficients of the linear objective function to be minimized.
- A_ub : 2-D array, optional
- The inequality constraint matrix. Each row of ``A_ub`` specifies the
- coefficients of a linear inequality constraint on ``x``.
- b_ub : 1-D array, optional
- The inequality constraint vector. Each element represents an
- upper bound on the corresponding value of ``A_ub @ x``.
- A_eq : 2-D array, optional
- The equality constraint matrix. Each row of ``A_eq`` specifies the
- coefficients of a linear equality constraint on ``x``.
- b_eq : 1-D array, optional
- The equality constraint vector. Each element of ``A_eq @ x`` must equal
- the corresponding element of ``b_eq``.
- bounds : sequence, optional
- A sequence of ``(min, max)`` pairs for each element in ``x``, defining
- the minimum and maximum values of that decision variable. Use ``None``
- to indicate that there is no bound. By default, bounds are
- ``(0, None)`` (all decision variables are non-negative).
- If a single tuple ``(min, max)`` is provided, then ``min`` and
- ``max`` will serve as bounds for all decision variables.
- method : str
- This is the method-specific documentation for 'simplex'.
- :ref:`'highs' <optimize.linprog-highs>`,
- :ref:`'highs-ds' <optimize.linprog-highs-ds>`,
- :ref:`'highs-ipm' <optimize.linprog-highs-ipm>`,
- :ref:`'interior-point' <optimize.linprog-interior-point>` (default),
- and :ref:`'revised simplex' <optimize.linprog-revised_simplex>`
- are also available.
- callback : callable, optional
- Callback function to be executed once per iteration.
- Options
- -------
- maxiter : int (default: 5000)
- The maximum number of iterations to perform in either phase.
- disp : bool (default: False)
- Set to ``True`` if indicators of optimization status are to be printed
- to the console each iteration.
- presolve : bool (default: True)
- Presolve attempts to identify trivial infeasibilities,
- identify trivial unboundedness, and simplify the problem before
- sending it to the main solver. It is generally recommended
- to keep the default setting ``True``; set to ``False`` if
- presolve is to be disabled.
- tol : float (default: 1e-12)
- The tolerance which determines when a solution is "close enough" to
- zero in Phase 1 to be considered a basic feasible solution or close
- enough to positive to serve as an optimal solution.
- autoscale : bool (default: False)
- Set to ``True`` to automatically perform equilibration.
- Consider using this option if the numerical values in the
- constraints are separated by several orders of magnitude.
- rr : bool (default: True)
- Set to ``False`` to disable automatic redundancy removal.
- bland : bool
- If True, use Bland's anti-cycling rule [3]_ to choose pivots to
- prevent cycling. If False, choose pivots which should lead to a
- converged solution more quickly. The latter method is subject to
- cycling (non-convergence) in rare instances.
- unknown_options : dict
- Optional arguments not used by this particular solver. If
- `unknown_options` is non-empty a warning is issued listing all
- unused options.
- Returns
- -------
- res : OptimizeResult
- A :class:`scipy.optimize.OptimizeResult` consisting of the fields:
- x : 1-D array
- The values of the decision variables that minimizes the
- objective function while satisfying the constraints.
- fun : float
- The optimal value of the objective function ``c @ x``.
- slack : 1-D array
- The (nominally positive) values of the slack variables,
- ``b_ub - A_ub @ x``.
- con : 1-D array
- The (nominally zero) residuals of the equality constraints,
- ``b_eq - A_eq @ x``.
- success : bool
- ``True`` when the algorithm succeeds in finding an optimal
- solution.
- status : int
- An integer representing the exit status of the algorithm.
- ``0`` : Optimization terminated successfully.
- ``1`` : Iteration limit reached.
- ``2`` : Problem appears to be infeasible.
- ``3`` : Problem appears to be unbounded.
- ``4`` : Numerical difficulties encountered.
- message : str
- A string descriptor of the exit status of the algorithm.
- nit : int
- The total number of iterations performed in all phases.
- References
- ----------
- .. [1] Dantzig, George B., Linear programming and extensions. Rand
- Corporation Research Study Princeton Univ. Press, Princeton, NJ,
- 1963
- .. [2] Hillier, S.H. and Lieberman, G.J. (1995), "Introduction to
- Mathematical Programming", McGraw-Hill, Chapter 4.
- .. [3] Bland, Robert G. New finite pivoting rules for the simplex method.
- Mathematics of Operations Research (2), 1977: pp. 103-107.
- """
- pass
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