LogarithmFD Component Specification

Overview

LogarithmFD component is a feature descriptor. This component produces the logarithm of an input. The scale of the input must be INTEGER or REAL.

Example:

  • SPD:

    dl1 -> log1
    
    ---
    
    components:
        dl1:
            component: DataLoader
    
        log1:
            component: LogarithmFDComponent
            features: scale == 'real' or scale == 'integer'
            base: 10
    
  • Input of the component:

_sid

temperature

pressure

0

22.3

1001

1

21.8

1002

2

inf

NaN

3

23.4

1002

4

-inf

1002

  • Output of the component:

_sid

log1_temperature

log1_pressure

0

1.348305

3.000434

1

1.338456

3.000868

2

inf

NaN

3

1.369216

3.000868

4

-inf

3.000868

This component has no component-specific external formats.

See also

Component-common external format files in convert_process


Parameters

Here is the component-specific parameter for the LogarithmFD component. Symbol \(\mathrm{e}\) is the Napier’s constant.

SPD

The following parameter is for “components” section of SPD.

Parameter Name

Type

Domain

Default Value

Description

base

float

2, 10, \(\mathrm{e}\)

\(\mathrm{e}\)

The base of a logarithm. This component produces logarithm values with respect to the base. If you like to designate \(\mathrm{e}\) (Napier’s constant) as base, please describe it as a character ‘e’ in SPD files as shown below:

base: 'e'

Utilizable Sample Metadata

There are no component-specific sample metadata available.


Output Attributes

LogarithmFD component generates the following attribute:

Attribute Name

Scale

Description

<component_id>_<original_attribute_name>

REAL

Logarithm of the original attribute.

These attributes are in the component output data. These can be loaded in SAMPO API or saved as data.csv after executing convert_process.

See also

Obtaining process results via ProcessResultLoader.


Attribute Metadata

The metadata of the output attributes is created with the following rules.

Context Rule

Attribute Name

Context Name

Description

<component_id>_<original_attribute_name>

base

Set the value of base.

Derivation Rule

Each new attribute is derived from the corresponding attribute selected by the features parameter of the component.

Example

{
    "nodes": [
        {"aid": "_sid", "name": "_sid", ... },
        {"aid": "dl1[0]", "name": "temperature", ... },
        {"aid": "dl1[1]", "name": "pressure", ... },
        {"aid": "log1[0]", "name": "log1_temperature", "scale": "real",
         "is_excluded": false, "cid": "log1", "cindex": 0, "values": null,
         "is_kept": false, "context": {"base": 10}},
        {"aid": "log1[1]", "name": "log1_pressure", "scale": "real",
         "is_excluded": false, "cid": "log1", "cindex": 1, "values": null,
         "is_kept": false, "context": {"base": 10}}
    ],
    "links": [
        {"source": "dl1[0]", "target": "log1[0]"},
        {"source": "dl1[1]", "target": "log1[1]"}
    ]
}

See also

Attribute metadata file format in Attribute Metadata File Specification


Details

  • In the learning phase, this component only checks if the base parameter is valid.

  • In the running phase, this component produces an output output value from an input input value as shown below:

    • input value is NaN:

      output value = NaN

    • input value \(\leq -\mathrm{e}\):

      output value = -log(- input value, base)

    • \(-\mathrm{e} \leq\) input value \(\leq \mathrm{e}\):

      output value = input value / (\(\mathrm{e} \times\) log(base, \(\mathrm{e}\)))

    • \(\mathrm{e} \leq\) input value:

      output value = log(input value, base)

    where log(x, base) is a function returns the logarithm of x to base.