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ENVICreateIterativeTrainerTask

ENVICreateIterativeTrainerTask

This task creates an iterative trainer that can train a classifier using ENVITrainClassifierTask.

The trainer uses an iterative loop to train a classifier that knows how to update its own weights; for example, Support Vector Machine (SVM). The trainer iteraties until the classifier's change in loss falls below a specified convergence criterion or it reaches a specified maximum number of iterations. The convergence criterion and maximum iterations needed to effectively train a classifier (not just each classifier type, but each classifier instance) can vary considerably. They often take some experimentation to determine.

The following diagram shows a typical workflow where this task is used:

 

Example


See Code Example: Support Vector Machine Classification using ENVITasks.

Syntax


Result = ENVITask('CreateIterativeTrainer')

Input properties (Set, Get): CONVERGENCE_CRITERION, MAXIMUM_ITERATIONS, OUTPUT_TRAINER_URI

Output properties (Get only): OUTPUT_TRAINER

Properties marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Properties marked as "Get" are those whose values you can retrieve but not set.

Methods


This task inherits the following methods from ENVITask:

AddParameter

Execute

Parameter

ParameterNames

RemoveParameter

Properties


This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

COMMUTE_ON_SUBSET

DESCRIPTION

DISPLAY_NAME

NAME

REVISION

TAGS

This task also contains the following properties:

CONVERGENCE_CRITERION (optional)

Specify a convergence criterion. Ideally, with each iteration, the change in loss value decreases until it meets a specified threshold, below which iterations can stop. This threshold is the convergence criterion. The default value is 0.001.

MAXIMUM_ITERATIONS (optional)

Specify the maximum number of iterations to perform if the convergence criterion is not met. The default value is 100.

OUTPUT_TRAINER

This is a reference to the initialized ENVIIterativeTrainer object.

OUTPUT_TRAINER_URI (optional)

Specify a string with the fully qualified filename and path of the output object. If you do not specify this property, the output object (.epo) is only temporary. Once ENVI is closed, it deletes the temporary file. Restore the object later using ENVIRestoreObject.ENVIIterativeTrainer is a persistable object that can be saved and restored.

Version History


ENVI 5.4

Introduced

API Version


3.3

See Also


ENVITask, ENVIIterativeTrainer, ENVICreateGradientDescentTrainerTask, ENVIRestoreObject



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