API Reference¶

API Summary¶

`InitialInfo`	Initial info data model
`PathInfo`	The named tuple with info about extracted path or piece of path
`PathInfoResult`	The named tuple with path info result
`TravelTimeOrder`	The enumeration of travel time computation orders
`OdeSolverMethod`	The enumeration of supported ODE solver methods
`Parameters`	MPE algorithm parameters model
`parameters`	Context manager for using specified parameters
`default_parameters`	Returns the default parameters
`MPEError`	Base exception class for all MPE errors
`ComputeTravelTimeError`	The exception occurs when computing travel time has failed
`PathExtractionError`	Base exception class for all extracting path errors
`EndPointNotReachedError`	The exception occurs when the ending point is not reached
`PathExtractionResult`	The named tuple with info about extracted path
`MinimalPathExtractor`	Minimal path extractor
`mpe`	Extracts a minimal path by start/end and optionally way points

Data and Models¶

class skmpe.InitialInfo¶

Initial info data model

speed_data¶: Speed data in numpy ndarray

start_point¶: The starting point

end_point¶: The ending point

way_points¶: The tuple of way points

all_points(self) → List[Sequence[int]]¶: Returns all initial points

point_intervals(self) → List[Tuple[Sequence[int], Sequence[int]]]¶: Returns the list of the tuples of initial point intervals

class skmpe.PathInfo¶

Bases: tuple

The named tuple with info about extracted path or piece of path

path¶: The path in numpy ndarray

start_point¶: The starting point

end_point¶: The ending point

travel_time¶: The travel time numpy ndarray

extraction_result¶: The path extraction result in PathExtractionResult that is returned by MinimalPathExtractor

reversed¶: The flag is true if the extracted path is reversed

class skmpe.PathInfoResult¶

Bases: tuple

The named tuple with path info result

path¶: Path data in numpy array

pieces¶: The tuple of PathInfo for every path piece

Parameters¶

class skmpe.TravelTimeOrder¶

Bases: enum.IntEnum

The enumeration of travel time computation orders

Orders:

first – the first ordered travel time computation

second – the second ordered travel time computation

first = 1¶

second = 2¶

class skmpe.OdeSolverMethod¶

Bases: str, enum.Enum

The enumeration of supported ODE solver methods

BDF = 'BDF'¶

DOP853 = 'DOP853'¶

LSODA = 'LSODA'¶

RK23 = 'RK23'¶

RK45 = 'RK45'¶

Radau = 'Radau'¶

class skmpe.Parameters¶

MPE algorithm parameters model

travel_time_spacing¶: The travel time computation spacing

default: 1.0

travel_time_order¶: The travel time computation order

default: TravelTimeOrder.first

travel_time_cache¶: Use or not travel time computation cache for extracting paths with way points

default: True

ode_solver_method¶: ODE solver method

default: ‘RK45’

integrate_time_bound¶: Integration time bound

default: 10000

integrate_min_step¶: Integration minimum step

default: 0.0

integrate_max_step¶: Integration maximum step

default: 4.0

dist_tol¶: Distance tolerance for control path evolution

default: 1e-03

max_small_dist_steps¶: The max number of small distance steps while path evolution

default: 100

dist_tol = None

integrate_max_step = None

integrate_min_step = None

integrate_time_bound = None

max_small_dist_steps = None

ode_solver_method = None

travel_time_cache = None

travel_time_order = None

travel_time_spacing = None

skmpe.parameters(**kwargs)¶

Context manager for using specified parameters

Parameters

kwargsmapping: The parameters

Examples

>>> from skmpe import parameters
>>> with parameters(integrate_time_bound=200000) as params:
>>>     print(params.__repr__())

Parameters(
    travel_time_spacing=1.0,
    travel_time_order=<TravelTimeOrder.first: 1>,
    travel_time_cache=False,
    ode_solver_method=<OdeSolverMethod.RK45: 'RK45'>,
    integrate_time_bound=200000.0,
    integrate_min_step=0.0,
    integrate_max_step=4.0,
    dist_tol=0.001,
    max_small_dist_steps=100
)

from skmpe import parameters, mpe

...

with parameters(integrate_time_bound=200000):
    path_result = mpe(start_point, end_point)

skmpe.default_parameters() → skmpe.Parameters¶

Returns the default parameters

Returns

parametersParameters: Default parameters

Examples

>>> from skmpe import default_parameters
>>> print(default_parameters().__repr__())

Parameters(
    travel_time_spacing=1.0,
    travel_time_order=<TravelTimeOrder.first: 1>,
    travel_time_cache=False,
    ode_solver_method=<OdeSolverMethod.RK45: 'RK45'>,
    integrate_time_bound=10000.0,
    integrate_min_step=0.0,
    integrate_max_step=4.0,
    dist_tol=0.001,
    max_small_dist_steps=100
)

Exceptions¶

class skmpe.MPEError¶

Bases: Exception

Base exception class for all MPE errors

class skmpe.ComputeTravelTimeError¶

Bases: skmpe.MPEError

The exception occurs when computing travel time has failed

class skmpe.PathExtractionError(*args, travel_time: numpy.ndarray, start_point: Sequence[int], end_point: Sequence[int])¶

Bases: skmpe.MPEError

Base exception class for all extracting path errors

property end_point¶: Ending point

property start_point¶: Starting point

property travel_time¶: Computed travel time data

class skmpe.EndPointNotReachedError(*args, travel_time: numpy.ndarray, start_point: Sequence[int], end_point: Sequence[int], extracted_points: List[Sequence[float]], last_distance: float, reason: str)¶

Bases: skmpe.PathExtractionError

The exception occurs when the ending point is not reached

property end_point¶: Ending point

property extracted_points¶: The list of extracted path points

property last_distance¶: The last distance to the ending point from the last path point

property reason¶: The reason of extracting path termination

property start_point¶: Starting point

property travel_time¶: Computed travel time data

Path Extraction¶

class skmpe.PathExtractionResult¶

Bases: tuple

The named tuple with info about extracted path

Notes

The instance of the class is returned from MinimalPathExtractor.__call__().

path_points¶: The extracted path points in the list

path_integrate_times¶: The list of integrate times for every path point

path_travel_times¶: The list of travel time values for every path point

step_count¶: The number of integration steps

func_eval_count¶: The number of evaluations of the right hand function

class skmpe.MinimalPathExtractor(speed_data: numpy.ndarray, end_point: Sequence[int], parameters: Optional[skmpe.Parameters] = None)¶

Minimal path extractor

Minimal path extractor based on the fast marching method and ODE solver.

Parameters

speed_datanp.ndarray: The speed data (n-d numpy array)
end_pointSequence[int]: The ending point (a.k.a. “source point”)
parametersclass:Parameters: The parameters

Raises

ComputeTravelTimeErrorComputing travel time has failed

Examples

from skmpe import MinimalPathExtractor

# some function for computing speed data
speed_data_2d = compute_speed_data_2d()

mpe = MinimalPathExtractor(speed_data_2d, end_point=(10, 25))
path = mpe((123, 34))

__call__(self, start_point: Sequence[int]) → skmpe.PathExtractionResult¶

Extract path from start point to source point (ending point)

Parameters

start_pointSequence[int]: The starting point

Returns

path_extraction_resultPathExtractionResult: The path extraction result

Raises

PathExtractionErrorExtracting path has failed
EndPointNotReachedErrorThe extracted path is not reached the ending point

property parameters¶: Returns the parameters

property phi¶: Returns the computed phi (zero contour) for given source point

property travel_time¶: Returns the computed travel time for given speed data

skmpe.mpe(*args, **kwargs) → skmpe.PathInfoResult¶

Extracts a minimal path by start/end and optionally way points

The function is high level API for extracting paths.

Parameters

init_infoInitialInfo: (sign 1) The initial info
start_pointSequence[int]: (sign 2) The starting point
end_pointSequence[int]: (sign 2) The ending point
way_pointsSequence[Sequence[int]]: (sign 2) The way points
parametersParameters: The parameters

Returns

path_infoPathInfoResult: Extracted path info

scikit-mpe

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Related Topics

API Reference¶

API Summary¶

Data and Models¶

Parameters¶

Exceptions¶

Path Extraction¶