gemseo / algos / opt

lib_snopt module

SNOPT optimization library wrapper.

class gemseo.algos.opt.lib_snopt.SNOPTAlgorithmDescription(algorithm_name, internal_algorithm_name, library_name='SNOPT', description='', website='', handle_integer_variables=False, require_gradient=False, handle_equality_constraints=False, handle_inequality_constraints=False, handle_multiobjective=False, positive_constraints=False, problem_type='non-linear')

Bases: OptimizationAlgorithmDescription

The description of an optimization algorithm from the SNOPT library.

Parameters:

• algorithm_name (str) –

• internal_algorithm_name (str) –

• library_name (str) –

  By default it is set to “SNOPT”.

• description (str) –

  By default it is set to “”.

• website (str) –

  By default it is set to “”.

• handle_integer_variables (bool) –

  By default it is set to False.

• require_gradient (bool) –

  By default it is set to False.

• handle_equality_constraints (bool) –

  By default it is set to False.

• handle_inequality_constraints (bool) –

  By default it is set to False.

• handle_multiobjective (bool) –

  By default it is set to False.

• positive_constraints (bool) –

  By default it is set to False.

• problem_type (str) –

  By default it is set to “non-linear”.

algorithm_name: str

The name of the algorithm in GEMSEO.

description: str = ''

A description of the algorithm.

handle_equality_constraints: bool = False

Whether the optimization algorithm handles equality constraints.

handle_inequality_constraints: bool = False

Whether the optimization algorithm handles inequality constraints.

handle_integer_variables: bool = False

Whether the optimization algorithm handles integer variables.

handle_multiobjective: bool = False

Whether the optimization algorithm handles multiple objectives.

internal_algorithm_name: str

The name of the algorithm in the wrapped library.

library_name: str = 'SNOPT'

The name of the wrapped library.

positive_constraints: bool = False

Whether the optimization algorithm requires positive constraints.

problem_type: str = 'non-linear'

The type of problem (see OptimizationProblem.AVAILABLE_PB_TYPES).

require_gradient: bool = False

Whether the optimization algorithm requires the gradient.

website: str = ''

The website of the wrapped library or algorithm.

class gemseo.algos.opt.lib_snopt.SnOpt

Bases: OptimizationLibrary

SNOPT optimization library interface.

See OptimizationLibrary.

Note

The missing current values of the DesignSpace attached to the OptimizationProblem are automatically initialized with the method DesignSpace.initialize_missing_current_values().

Constructor.

Generate the library dict, contains the list of algorithms with their characteristics:

• does it require gradient,

• does it handle equality constraints,

• does it handle inequality constraints.

algorithm_handles_eqcstr(algo_name)

Check if an algorithm handles equality constraints.

Parameters:

algo_name (str) – The name of the algorithm.

Returns:

Whether the algorithm handles equality constraints.

Return type:

bool

algorithm_handles_ineqcstr(algo_name)

Check if an algorithm handles inequality constraints.

Parameters:

algo_name (str) – The name of the algorithm.

Returns:

Whether the algorithm handles inequality constraints.

Return type:

bool

cb_opt_constraints_snoptb(mode, nn_con, nn_jac, ne_jac, xn_vect, n_state)

Evaluate the constraint functions and their gradient.

Use the snOpt conventions (from web.stanford.edu/group/SOL/guides/sndoc7.pdf).

Parameters:

• mode (int) – A flag that indicates whether the obj, the gradient or both must be assigned during the present call of function (0 ≤ mode ≤ 2). mode = 2, assign obj and the known components of gradient. mode = 1, assign the known components of gradient. obj is ignored. mode = 0, only obj need be assigned; gradient is ignored.

• nn_con (int) – The number of non-linear constraints.

• nn_jac (int) – The number of dv involved in non-linear constraint functions.

• ne_jac (int) – The number of non-zero elements in the constraints gradient. If dcstr is 2D, then ne_jac = nn_con*nn_jac.

• xn_vect (ndarray) – The normalized design vector.

• n_state (int) – An indicator for the first and last call to the current function n_state = 0: NTR. n_state = 1: first call to driver.cb_opt_objective_snoptb. n_state > 1, snOptB is calling subroutine for the last time and: n_state = 2 and the current x is optimal n_state = 3, the problem appears to be infeasible n_state = 4, the problem appears to be unbounded; n_state = 5, an iterations limit was reached.

Returns:

The solution status, the evaluation of the constraint function and its gradient.

Return type:

tuple[int, numpy.ndarray, numpy.ndarray]

cb_opt_objective_snoptb(mode, nn_obj, xn_vect, n_state=0)

Evaluate the objective function and gradient.

Use the snOpt conventions for mode and status (from web.stanford.edu/group/SOL/guides/sndoc7.pdf).

Parameters:

• mode (int) – Flag to indicate whether the obj, the gradient or both must be assigned during the present call of the function (0 \(\leq\) mode \(\leq\) 2). mode = 2, assign the obj and the known components of the gradient. mode = 1, assign the known components of gradient. obj is ignored. mode = 0, only the obj needs to be assigned; the gradient is ignored.

• nn_obj (int) – The number of design variables.

• xn_vect (ndarray) – The normalized design vector.

• n_state (int) –

  An indicator for the first and last call to the current function. n_state = 0: NTR. n_state = 1: first call to driver.cb_opt_objective_snoptb. n_state > 1, snOptB is calling subroutine for the last time and: n_state = 2 and the current x is optimal n_state = 3, the problem appears to be infeasible n_state = 4, the problem appears to be unbounded; n_state = 5, an iterations limit was reached.

  By default it is set to 0.

Returns:

The solution status, the evaluation of the objective function and its gradient.

Return type:

tuple[int, numpy.ndarray, numpy.ndarray]

static cb_snopt_dummy_func(mode, nn_con, nn_jac, ne_jac, xn_vect, n_state)

Return a dummy output for unconstrained problems.

Parameters:

• mode (int) – A flag that indicates whether the obj, the gradient or both must be assigned during the present call of function (0 ≤ mode ≤ 2). mode = 2, assign obj and the known components of gradient. mode = 1, assign the known components of gradient. obj is ignored. mode = 0, only obj need be assigned; gradient is ignored.

• nn_con (int) – The number of non-linear constraints.

• nn_jac (int) – The number of dv involved in non-linear constraint functions.

• ne_jac (int) – The number of non-zero elements in the constraints gradient. If dcstr is 2D, then ne_jac = nn_con*nn_jac.

• xn_vect (ndarray) – The normalized design vector.

• n_state (int) – An indicator for the first and last call to the current function n_state = 0: NTR. n_state = 1: first call to driver.cb_opt_objective_snoptb. n_state > 1, snOptB is calling subroutine for the last time and: n_state = 2 and the current x is optimal n_state = 3, the problem appears to be infeasible n_state = 4, the problem appears to be unbounded; n_state = 5, an iterations limit was reached.

Returns:

A dummy output.

Return type:

float

deactivate_progress_bar()

Deactivate the progress bar.

Return type:

None

driver_has_option(option_name)

Check the existence of an option.

Parameters:

option_name (str) – The name of the option.

Returns:

Whether the option exists.

Return type:

bool

ensure_bounds(orig_func, normalize=True)

Project the design vector onto the design space before execution.

Parameters:

• orig_func – The original function.

• normalize –

  Whether to use the normalized design space.

  By default it is set to True.

Returns:

A function calling the original function with the input data projected onto the design space.

execute(problem, algo_name=None, eval_obs_jac=False, skip_int_check=False, **options)

Execute the driver.

Parameters:

• problem (OptimizationProblem) – The problem to be solved.

• algo_name (str | None) – The name of the algorithm. If None, use the algo_name attribute which may have been set by the factory.

• eval_obs_jac (bool) –

  Whether to evaluate the Jacobian of the observables.

  By default it is set to False.

• skip_int_check (bool) –

  Whether to skip the integer variable handling check of the selected algorithm.

  By default it is set to False.

• **options (DriverLibOptionType) – The options for the algorithm.

Returns:

The optimization result.

Raises:

ValueError – If algo_name was not either set by the factory or given as an argument.

Return type:

OptimizationResult

filter_adapted_algorithms(problem)

Filter the algorithms capable of solving the problem.

Parameters:

problem (Any) – The problem to be solved.

Returns:

The names of the algorithms adapted to this problem.

Return type:

list[str]

finalize_iter_observer()

Finalize the iteration observer.

Return type:

None

get_optimum_from_database(message=None, status=None)

Retrieve the optimum from the database and build an optimization.

get_right_sign_constraints()

Transform the problem constraints into their opposite sign counterpart.

This is done if the algorithm requires positive constraints.

get_x0_and_bounds_vects(normalize_ds)

Return x0 and bounds.

Parameters:

normalize_ds – Whether to normalize the input variables that are not integers, according to the normalization policy of the design space.

Returns:

The current value, the lower bounds and the upper bounds.

init_iter_observer(max_iter, message='...')

Initialize the iteration observer.

It will handle the stopping criterion and the logging of the progress bar.

Parameters:

• max_iter (int) – The maximum number of iterations.

• message (str) –

  The message to display at the beginning.

  By default it is set to “…”.

Raises:

ValueError – If max_iter is lower than one.

Return type:

None

init_options_grammar(algo_name)

Initialize the options’ grammar.

Parameters:

algo_name (str) – The name of the algorithm.

Return type:

JSONGrammar

is_algo_requires_grad(algo_name)

Returns True if the algorithm requires a gradient evaluation.

Parameters:

algo_name – The name of the algorithm.

is_algo_requires_positive_cstr(algo_name)

Check if an algorithm requires positive constraints.

Parameters:

algo_name (str) – The name of the algorithm.

Returns:

Whether the algorithm requires positive constraints.

Return type:

bool

classmethod is_algorithm_suited(algorithm_description, problem)

Check if an algorithm is suited to a problem according to its description.

Parameters:

• algorithm_description (AlgorithmDescription) – The description of the algorithm.

• problem (Any) – The problem to be solved.

Returns:

Whether the algorithm is suited to the problem.

Return type:

bool

new_iteration_callback(x_vect=None)

Verify the design variable and objective value stopping criteria.

Parameters:

x_vect (ndarray | None) – The design variables values. If None, use the values of the last iteration.

Raises:

• FtolReached – If the defined relative or absolute function tolerance is reached.

• XtolReached – If the defined relative or absolute x tolerance is reached.

Return type:

None

COMPLEX_STEP_METHOD = 'complex_step'

DIFFERENTIATION_METHODS = ['user', 'complex_step', 'finite_differences']

EQ_TOLERANCE = 'eq_tolerance'

EVAL_OBS_JAC_OPTION = 'eval_obs_jac'

FINITE_DIFF_METHOD = 'finite_differences'

F_TOL_ABS = 'ftol_abs'

F_TOL_REL = 'ftol_rel'

INEQ_TOLERANCE = 'ineq_tolerance'

LIBRARY_NAME: ClassVar[str | None] = 'SNOPT'

The name of the interfaced library.

LIB_COMPUTE_GRAD = False

LS_STEP_NB_MAX = 'max_ls_step_nb'

LS_STEP_SIZE_MAX = 'max_ls_step_size'

MAX_DS_SIZE_PRINT = 40

MAX_FUN_EVAL = 'max_fun_eval'

MAX_ITER = 'max_iter'

MAX_TIME = 'max_time'

MESSAGES_DICT = {1: 'optimality conditions satisfied', 2: 'feasible point found', 3: 'requested accuracy could not be achieved', 11: 'infeasible linear constraints', 12: 'infeasible linear equalities', 13: 'nonlinear infeasibilities minimized', 14: 'infeasibilities minimized', 21: 'unbounded objective', 22: 'constraint violation limit reached', 31: 'iteration limit reached', 32: 'major iteration limit reached', 33: 'the superbasics limit is too small', 41: 'current point cannot be improved ', 42: 'singular basis', 43: 'cannot satisfy the general constraints', 44: 'ill-conditioned null-space basis', 51: 'incorrect objective derivatives', 52: 'incorrect constraint derivatives', 61: 'undefined function at the first feasible point', 62: 'undefined function at the initial point', 63: 'unable to proceed into undefined region', 72: 'terminated during constraint evaluation', 73: 'terminated during objective evaluation', 74: 'terminated from monitor routine', 81: 'work arrays must have at least 500 elements', 82: 'not enough character storage', 83: 'not enough integer storage', 84: 'not enough real storage', 91: 'invalid input argument', 92: 'basis file dimensions do not match this problem', 141: 'wrong number of basic variables', 142: 'error in basis package'}

NORMALIZE_DESIGN_SPACE_OPTION = 'normalize_design_space'

OPTIONS_DIR: Final[str] = 'options'

The name of the directory containing the files of the grammars of the options.

OPTIONS_MAP: dict[str, str] = {'max_iter': 'Iteration_limit'}

The names of the options in GEMSEO mapping to those in the wrapped library.

PG_TOL = 'pg_tol'

ROUND_INTS_OPTION = 'round_ints'

STOP_CRIT_NX = 'stop_crit_n_x'

USER_DEFINED_GRADIENT = 'user'

USE_DATABASE_OPTION = 'use_database'

VERBOSE = 'verbose'

X_TOL_ABS = 'xtol_abs'

X_TOL_REL = 'xtol_rel'

activate_progress_bar: ClassVar[bool] = True

Whether to activate the progress bar in the optimization log.

algo_name: str | None

The name of the algorithm used currently.

property algorithms: list[str]

The available algorithms.

descriptions: dict[str, AlgorithmDescription]

The description of the algorithms contained in the library.

internal_algo_name: str | None

The internal name of the algorithm used currently.

It typically corresponds to the name of the algorithm in the wrapped library if any.

opt_grammar: JSONGrammar | None

The grammar defining the options of the current algorithm.

problem: Any | None

The problem to be solved.