opytimizer.optimizers.population.loa

Lion Optimization Algorithm.

class opytimizer.optimizers.population.loa.Lion

A Lion class complements its inherited parent with additional information neeeded by the Lion Optimization Algorithm.

__init__()

Initialization method.

Parameters:
  • n_variables – Number of decision variables.
  • n_dimensions – Number of dimensions.
  • lower_bound – Minimum possible values.
  • upper_bound – Maximum possible values.
  • position – Position array.
  • fit – Fitness value.
best_position

N-dimensional array of best positions.

p_fit

Previous fitness value.

nomad

Whether lion is nomad or not.

Type:bool
female

Whether lion is female or not.

pride

Index of pride.

group

Index of hunting group.

class opytimizer.optimizers.population.loa.LOA(params: Optional[Dict[str, Any]] = None)

An LOA class, inherited from Optimizer.

This is the designed class to define LOA-related variables and methods.

References

M. Yazdani and F. Jolai. Lion Optimization Algorithm (LOA): A nature-inspired metaheuristic algorithm. Journal of Computational Design and Engineering (2016).

__init__(params: Optional[Dict[str, Any]] = None) → None

Initialization method.

Parameters:params – Contains key-value parameters to the meta-heuristics.
N

Percentage of nomad lions.

P

Number of prides.

S

Percentage of female lions.

R

Percentage of roaming lions.

I

Immigrate rate.

Ma

Mating probability.

Mu

Mutation probability.

compile(space: opytimizer.core.space.Space) → None

Compiles additional information that is used by this optimizer.

Parameters:space – A Space object containing meta-information.
_get_nomad_lions(agents: List[opytimizer.optimizers.population.loa.Lion]) → List[opytimizer.optimizers.population.loa.Lion]

Gets all nomad lions.

Parameters:agents – Agents.
Returns:A list of nomad lions.
Return type:(List[Lion])
_get_pride_lions(agents: List[opytimizer.optimizers.population.loa.Lion]) → List[List[opytimizer.optimizers.population.loa.Lion]]

Gets all non-nomad (pride) lions.

Parameters:agents – Agents.
Returns:A list of lists, where each one indicates a particular pride with its lions.
Return type:(List[List[Lion]])
_hunting(prides: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → None

Performs the hunting procedure (s. 2.2.2).

Parameters:
  • prides – List of prides holding their corresponding lions.
  • function – A Function object that will be used as the objective function.
_moving_safe_place(prides: List[opytimizer.optimizers.population.loa.Lion]) → None

Move prides to safe locations (s. 2.2.3).

Parameters:prides – List of prides holding their corresponding lions.
_roaming(prides: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → None

Performs the roaming procedure (s. 2.2.4).

Parameters:
  • prides – List of prides holding their corresponding lions.
  • function – A Function object that will be used as the objective function.
_mating_operator(agent: List[opytimizer.optimizers.population.loa.Lion], males: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → Tuple[opytimizer.optimizers.population.loa.Lion, opytimizer.optimizers.population.loa.Lion]

Wraps the mating operator.

Parameters:
  • agent – Current agent.
  • males – List of males that will be breed.
  • function – A Function object that will be used as the objective function.
Returns:

A pair of offsprings that resulted from mating.
Return type:

(Tuple[Lion, Lion])
_mating(prides: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → opytimizer.optimizers.population.loa.Lion

Generates offsprings from mating (s. 2.2.5).

Parameters:
  • prides – List of prides holding their corresponding lions.
  • function – A Function object that will be used as the objective function.
Returns:

Cubs generated from the mating procedure.
Return type:

(Lion)
_defense(nomads: List[opytimizer.optimizers.population.loa.Lion], prides: List[List[opytimizer.optimizers.population.loa.Lion]], cubs: List[opytimizer.optimizers.population.loa.Lion]) → Tuple[List[opytimizer.optimizers.population.loa.Lion], List[List[opytimizer.optimizers.population.loa.Lion]]]

Performs the defense procedure (s. 2.2.6).

Parameters:
  • nomads – Nomad lions.
  • prides – List of prides holding their corresponding lions.
  • cubs – List of cubs holding their corresponding lions.
Returns:

Both updated nomad and pride lions.
Return type:

(Tuple[List[Lion], List[List[Lion]]])
_nomad_roaming(nomads: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → None

Performs the roaming procedure for nomad lions (s. 2.2.4).

Parameters:
  • nomads – Nomad lions.
  • function – A Function object that will be used as the objective function.
_nomad_mating(nomads: List[opytimizer.optimizers.population.loa.Lion], function: opytimizer.core.function.Function) → List[opytimizer.optimizers.population.loa.Lion]

Generates offsprings from nomad lions mating (s. 2.2.5).

Parameters:
  • nomads – Nomad lions.
  • function – A Function object that will be used as the objective function.
Returns:

Updated nomad lions.
Return type:

(List[Lion])
_nomad_attack(nomads: List[opytimizer.optimizers.population.loa.Lion], prides: List[List[opytimizer.optimizers.population.loa.Lion]]) → Tuple[List[opytimizer.optimizers.population.loa.Lion], List[List[opytimizer.optimizers.population.loa.Lion]]]

Performs the nomad’s attacking procedure (s. 2.2.6).

Parameters:
  • nomads – Nomad lions.
  • prides – List of prides holding their corresponding lions.
Returns:

Both updated nomad and pride lions.
Return type:

(Tuple[List[Lion], List[List[Lion]]])
_migrating(nomads: List[opytimizer.optimizers.population.loa.Lion], prides: List[List[opytimizer.optimizers.population.loa.Lion]]) → Tuple[List[opytimizer.optimizers.population.loa.Lion], List[List[opytimizer.optimizers.population.loa.Lion]]]

Performs the nomad’s migration procedure (s. 2.2.7).

Parameters:
  • nomads – Nomad lions.
  • prides – List of prides holding their corresponding lions.
Returns:

Both updated nomad and pride lions.
Return type:

(Tuple[List[Lion], List[List[Lion]]])
_equilibrium(nomads: List[opytimizer.optimizers.population.loa.Lion], prides: List[List[opytimizer.optimizers.population.loa.Lion]], n_agents: List[opytimizer.core.agent.Agent]) → Tuple[List[opytimizer.optimizers.population.loa.Lion], List[List[opytimizer.optimizers.population.loa.Lion]]]

Performs the population’s equilibrium procedure (s. 2.2.8).

Parameters:
  • nomads – Nomad lions.
  • prides – List of prides holding their corresponding lions.
Returns:

Both updated nomad and pride lions.
Return type:

(Tuple[List[Lion], List[List[Lion]]])
_check_prides_for_males(prides: List[List[opytimizer.optimizers.population.loa.Lion]]) → None

Checks if there is at least one male per pride.

Parameters:prides – List of prides holding their corresponding lions.
update(space: opytimizer.core.space.Space, function: opytimizer.core.function.Function) → None

Wraps Lion Optimization Algorithm over all agents and variables.

Parameters:
  • space – Space containing agents and update-related information.
  • function – A Function object that will be used as the objective function.