ScalarField

ScalarField

new ScalarField(parameters)

Description:

  • Implements a real-value function on a symboling space.

    ScalarField parameters

    General parameter

    • type: ... The type element used to calculate the distance, mandatory, default is "value".
    • epsilon: ... The threshold between to indistinguishable numerical value, default is 1e-12.
    • points: Optionally defines trajectory weighted points calling the add() method.
    • verbose: ... If true print the interpolation, extrapolation and barycenter intermediate values. Default is false.
Parameters:
Name Type Description
parameters JSON | String

The scalar-field parameters.

Methods

getParameters() → {JSON}

Description:

  • Returns the trajectory parameters.

Returns:

The trajectory parameters.

Type
JSON

setParameters(parameters) → {ScalarField}

Description:

  • Modifies some ScalarField parameters.

    • All parameters but the type can be modified.
    • The ScalarField points are preserved when changing the parameters, thus using the points field simply adds the points.
Parameters:
Name Type Description
parameters JSON

The Trajectory parameters.
Returns:

This value allowing to chain methods.

Type
ScalarField

set(input, outputopt) → {ScalarField}

Description:

  • Adds/Replaces a punctual value for this scalar-field.

Parameters:
Name Type Attributes Default Description
input Value

The input data structure
output double <optional>
 NAN

The corresponding output value.

  • If equals NAN the value is undefined, and only used for extrapolation.
Returns:

This value allowing to chain add methods.

Type
ScalarField

erase(input) → {ScalarField}

Description:

  • Deletes a punctual value for this scalar-field.

Parameters:
Name Type Description
input Value

The input data structure
Returns:

This value allowing to chain add methods.

Type
ScalarField

clear(input) → {ScalarField}

Description:

  • Deletes all values of this scalar-field.

Parameters:
Name Type Description
input Value

The input data structure
Returns:

This value allowing to chain add methods.

Type
ScalarField

add(field) → {ScalarField}

Description:

  • Adds all values of a scalar-field to this one.

Parameters:
Name Type Description
field ScalarField | JSON | String

The scalar-field to copy or the scalar-field value or values.

  • The scalar-field value's type must be compatible (i.e., the same type or a derived type) of this scalar value type.
  • It can also be defined as a JSON unordered list of value of syntax:
[
  { input_1: ... output_1: ... }
  ../..
]
  • It can also be defined as a JSON unordered list of undefined value of syntax:
[
  input_1
  ../..
]
  • It can also be defined as a unique value
{ input: ... output: ... }
  • It can also be defined as a unique undefined value.
Returns:

This value allowing to chain add methods.

Type
ScalarField

load(filename) → {ScalarField}

Description:

  • Loads all values of a scalar-field strored in a wJSON or JSON file.

    • It is short-cut for add(wjson::string2json(aidesys::load(filename))).
Parameters:
Name Type Description
filename String

The file name.
Returns:

This value allowing to chain add methods.

Type
ScalarField

save(filename, prettyopt, strictopt)

Description:

  • Saves all values of a scalar-field strored in a wjson file.

    • It is short-cut for aidesys::save(filename, getValues().asString(pretty, strict)).
Parameters:
Name Type Attributes Default Description
filename String

The file name.
pretty bool <optional>
 false

If true properly format in 2D, else returns a minimal raw format.
strict bool <optional>
 false

If true strict JSON syntax, else produces a weak JSON syntax.

getValues() → {JSON}

Description:

  • Returns the scalar-field defined values.

Returns:

The current scalar-field values:

[
  { input: ... output: ... }
  ../..
]
Type
JSON

has(input, NaNopt) → {bool}

Description:

  • Returns true if the point is stored in the field table.

Parameters:
Name Type Attributes Default Description
input JSON

The data point to check.
NaN bool <optional>
 false

If true includes also points with not-a-number output value.
Returns:

True if the point is explicitly stored.

Type
bool

get()

Description:

  • Defines an iterator over the scalarfield values, used in a construct of the form:

     for(auto it = scalarfield.get().cbegin(); it != scalarfield.get().cend(); it++) {
   JSON input& = it->first;
   double output = it->second;
   ../..
 }
    • The scalarfield.get().size() construct returns the number of predefined values in this field.
    • The scalarfield.edit() construct returns a modifiable std::unordered_map < wjson::Value, double > allowing to edit the predefined values.
Returns:

A const std::unordered_map < wjson::Value, double >& reference for iteration.

getValue(input, K_maxopt, d_maxopt, save_interpolationopt) → {double}

Description:

  • Returns a punctual interpolated value for this scalar-field.

    • Parameters can also be specified via the ScalarField "K_max", "d_max", "save_interpolation" parameters.
Parameters:
Name Type Attributes Default Description
input Value

The input data structure
K_max uint <optional>
 -1

The maximal cardinal of the interpolation neighborhood:

  • 0: Returns the exact value if set, and NAN otherwise.
  • 1: Returns the closest exact value.
  • 2: Returns the closest value on the path between the two closest value.
  • > 2: Reduces iteratively the neighborhood size by interpolating the value
    • between the closest values in the neighborhood,
    • choosing the value which as the closest to the input.
  • -1: Unbounded neighborhood cardinal, only the maximal distance is considered.
d_max double <optional>
 DBL_MAX

The maximal neighborhood distance, unbounded if equals to NAN.
save_interpolation bool <optional>
 false

If true save the interpolatd value for further use.
Returns:

The exact or interpolated value, 0 by default.

Type
double

getExtrapolations(input, reference, d_maxopt, nu_maxopt, bounds_countopt) → {Value}

Description:

  • Returns extrapolated values for this scalar-field.

    • Given type bounds to input related geodesics, the points below d_max, on the bound geodesics are computed, as soon as their distance to the reference is higher that for the input.
    • Parameters can also be specified via the ScalarField "d_max", "nu_max", "bound_counts" parameters.
Parameters:
Name Type Attributes Default Description
input Value

The input data structure.
reference Value

The reference data structure.
d_max double <optional>
 DBL_MAX

The maximal neighborhood distance, unbounded if equals to DBL_MAX or NAN.
nu_max double <optional>
 DBL_MAX

The maximal deviation nu = d(value, input) + d(input, reference) - d(value, reference) from the geodesic equality, unbounded if equals to DBL_MAX or NAN.
bounds_count int <optional>
 0

The type bounds count to be taken into account. By default all bounds are considered.
Returns:

A list of extrapolated data structures value approximating the prolongation of the input with respect to the reference.

Type
Value

getBarycenter() → {value}

Description:

  • Returns the weighted centroid value of the scalar-field.

    • Iteratively
      • detect the closest values and consider the path between them
      • choosing in their path the value which distance balance corresponds as much as possible to the two values relative weight.
    • This is illustrated on this tiny demo page.
Returns:

A data structure value which distance to the other values is weighted by the scalar-field values.

Type
value

getDiameter() → {double}

Description:

  • Returns the maximal distance between all predefined values.

Returns:

The computed diameter.

Type
double

getDistance(lhs, rhs) → {double}

Description:

  • Returns the distance between two data value, given the ScalarField type.

    • Values are cached avoiding to be recalculated twice.
Parameters:
Name Type Description
lhs Value

The left hand data structure.
rhs Value

The left hand data structure.
Returns:

The distance value.

Type
double