ORTTrainingSession Class Reference


                    
                    
                    -init

Unavailable

Declaration

Objective-C

- (instancetype)init NS_UNAVAILABLE;


                    
                    
                    -initWithEnv:sessionOptions:checkpoint:trainModelPath:evalModelPath:optimizerModelPath:error:

Creates a training session from the training artifacts that can be used to begin or resume training.

The initializer instantiates the training session based on provided env and session options, which can be used to begin or resume training from a given checkpoint state. The checkpoint state represents the parameters of training session which will be moved to the device specified in the session option if needed.

Note

Note that the training session created with a checkpoint state uses this state to store the entire training state (including model parameters, its gradients, the optimizer states and the properties). The training session keeps a strong (owning) pointer to the checkpoint state.

Declaration

Objective-C

- (nullable instancetype)initWithEnv:(nonnull ORTEnv *)env
                      sessionOptions:
                          (nullable ORTSessionOptions *)sessionOptions
                          checkpoint:(nonnull ORTCheckpoint *)checkpoint
                      trainModelPath:(nonnull NSString *)trainModelPath
                       evalModelPath:(nullable NSString *)evalModelPath
                  optimizerModelPath:(nullable NSString *)optimizerModelPath
                               error:(NSError *_Nullable *_Nullable)error;

Swift

init(env: ORTEnv, sessionOptions: ORTSessionOptions?, checkpoint: ORTCheckpoint, trainModelPath: String, evalModelPath: String?, optimizerModelPath: String?) throws

Parameters

`env`	The `ORTEnv` instance to use for the training session.
`sessionOptions`	The optional `ORTSessionOptions` to use for the training session.
`checkpoint`	Training states that are used as a starting point for training.
`trainModelPath`	The path to the training onnx model.
`evalModelPath`	The path to the evaluation onnx model.
`optimizerModelPath`	The path to the optimizer onnx model used to perform gradient descent.
`error`	Optional error information set if an error occurs.

Return Value

The instance, or nil if an error occurs.


                    
                    
                    -trainStepWithInputValues:error:

Performs a training step, which is equivalent to a forward and backward propagation in a single step.

The training step computes the outputs of the training model and the gradients of the trainable parameters for the given input values. The train step is performed based on the training model that was provided to the training session. It is equivalent to running forward and backward propagation in a single step. The computed gradients are stored inside the training session state so they can be later consumed by optimizerStep. The gradients can be lazily reset by calling lazyResetGrad method.

Declaration

Objective-C

- (nullable NSArray<ORTValue *> *)
    trainStepWithInputValues:(nonnull NSArray<ORTValue *> *)inputs
                       error:(NSError *_Nullable *_Nullable)error;

Swift

func trainStep(withInputValues inputs: [ORTValue]) throws -> [ORTValue]

Parameters

`inputs`	The input values to the training model.
`error`	Optional error information set if an error occurs.

Return Value

The output values of the training model.


                    
                    
                    -evalStepWithInputValues:error:

Performs a evaluation step that computes the outputs of the evaluation model for the given inputs. The eval step is performed based on the evaluation model that was provided to the training session.

Declaration

Objective-C

- (nullable NSArray<ORTValue *> *)
    evalStepWithInputValues:(nonnull NSArray<ORTValue *> *)inputs
                      error:(NSError *_Nullable *_Nullable)error;

Swift

func evalStep(withInputValues inputs: [ORTValue]) throws -> [ORTValue]

Parameters

`inputs`	The input values to the eval model.
`error`	Optional error information set if an error occurs.

Return Value

The output values of the eval model.


                    
                    
                    -lazyResetGradWithError:

Reset the gradients of all trainable parameters to zero lazily.

Calling this method sets the internal state of the training session such that the gradients of the trainable parameters in the ORTCheckpoint will be scheduled to be reset just before the new gradients are computed on the next invocation of the trainStep method.

Declaration

Objective-C

- (BOOL)lazyResetGradWithError:(NSError *_Nullable *_Nullable)error;

Swift

func lazyResetGrad() throws

Parameters


                                error

Optional error information set if an error occurs.

Return Value

YES if the gradients are set to reset successfully, NO otherwise.


                    
                    
                    -optimizerStepWithError:

Performs the weight updates for the trainable parameters using the optimizer model. The optimizer step is performed based on the optimizer model that was provided to the training session. The updated parameters are stored inside the training state so that they can be used by the next trainStep method call.

Declaration

Objective-C

- (BOOL)optimizerStepWithError:(NSError *_Nullable *_Nullable)error;

Swift

func optimizerStep() throws

Parameters


                                error

Optional error information set if an error occurs.

Return Value

YES if the optimizer step was performed successfully, NO otherwise.


                    
                    
                    -getTrainInputNamesWithError:

Returns the names of the user inputs for the training model that can be associated with the ORTValue provided to the trainStep.

Declaration

Objective-C

- (nullable NSArray<NSString *> *)getTrainInputNamesWithError:
    (NSError *_Nullable *_Nullable)error;

Swift

func getTrainInputNames() throws -> [String]

Parameters


                                error

Optional error information set if an error occurs.

Return Value

The names of the user inputs for the training model.


                    
                    
                    -getEvalInputNamesWithError:

Returns the names of the user inputs for the evaluation model that can be associated with the ORTValue provided to the evalStep.

Declaration

Objective-C

- (nullable NSArray<NSString *> *)getEvalInputNamesWithError:
    (NSError *_Nullable *_Nullable)error;

Swift

func getEvalInputNames() throws -> [String]

Parameters


                                error

Optional error information set if an error occurs.

Return Value

The names of the user inputs for the evaluation model.


                    
                    
                    -getTrainOutputNamesWithError:

Returns the names of the user outputs for the training model that can be associated with the ORTValue returned by the trainStep.

Declaration

Objective-C

- (nullable NSArray<NSString *> *)getTrainOutputNamesWithError:
    (NSError *_Nullable *_Nullable)error;

Swift

func getTrainOutputNames() throws -> [String]

Parameters


                                error

Optional error information set if an error occurs.

Return Value

The names of the user outputs for the training model.


                    
                    
                    -getEvalOutputNamesWithError:

Returns the names of the user outputs for the evaluation model that can be associated with the ORTValue returned by the evalStep.

Declaration

Objective-C

- (nullable NSArray<NSString *> *)getEvalOutputNamesWithError:
    (NSError *_Nullable *_Nullable)error;

Swift

func getEvalOutputNames() throws -> [String]

Parameters


                                error

Optional error information set if an error occurs.

Return Value

The names of the user outputs for the evaluation model.


                    
                    
                    -registerLinearLRSchedulerWithWarmupStepCount:totalStepCount:initialLr:error:

Registers a linear learning rate scheduler for the training session.

The scheduler gradually decreases the learning rate from the initial value to zero over the course of the training. The decrease is performed by multiplying the current learning rate by a linearly updated factor. Before the decrease, the learning rate is gradually increased from zero to the initial value during a warmup phase.

Declaration

Objective-C

- (BOOL)
    registerLinearLRSchedulerWithWarmupStepCount:(int64_t)warmupStepCount
                                  totalStepCount:(int64_t)totalStepCount
                                       initialLr:(float)initialLr
                                           error:(NSError *_Nullable *_Nullable)
                                                     error;

Swift

func registerLinearLRScheduler(withWarmupStepCount warmupStepCount: Int64, totalStepCount: Int64, initialLr: Float) throws

Parameters

`warmupStepCount`	The number of steps to perform the linear warmup.
`totalStepCount`	The total number of steps to perform the linear decay.
`initialLr`	The initial learning rate.
`error`	Optional error information set if an error occurs.

Return Value

YES if the scheduler was registered successfully, NO otherwise.


                    
                    
                    -schedulerStepWithError:

Update the learning rate based on the registered learning rate scheduler.

Performs a scheduler step that updates the learning rate that is being used by the training session. This function should typically be called before invoking the optimizer step for each round, or as necessary to update the learning rate being used by the training session.

Note

A valid predefined learning rate scheduler must be first registered to invoke this method.

Declaration

Objective-C

- (BOOL)schedulerStepWithError:(NSError *_Nullable *_Nullable)error;

Swift

func schedulerStep() throws

Parameters


                                error

Optional error information set if an error occurs.

Return Value

YES if the scheduler step was performed successfully, NO otherwise.


                    
                    
                    -getLearningRateWithError:

Returns the current learning rate being used by the training session.

Declaration

Objective-C

- (float)getLearningRateWithError:(NSError *_Nullable *_Nullable)error;

Swift

func getLearningRate() throws -> Float

Parameters


                                error

Optional error information set if an error occurs.

Return Value

The current learning rate or 0.0f if an error occurs.


                    
                    
                    -setLearningRate:error:

Sets the learning rate being used by the training session.

The current learning rate is maintained by the training session and can be overwritten by invoking this method with the desired learning rate. This function should not be used when a valid learning rate scheduler is registered. It should be used either to set the learning rate derived from a custom learning rate scheduler or to set a constant learning rate to be used throughout the training session.

Note

It does not set the initial learning rate that may be needed by the predefined learning rate schedulers. To set the initial learning rate for learning rate schedulers, use the registerLinearLRScheduler method.

Declaration

Objective-C

- (BOOL)setLearningRate:(float)lr error:(NSError *_Nullable *_Nullable)error;

Swift

func setLearningRate(_ lr: Float) throws

Parameters

`lr`	The learning rate to be used by the training session.
`error`	Optional error information set if an error occurs.

Return Value

YES if the learning rate was set successfully, NO otherwise.


                    
                    
                    -fromBufferWithValue:error:

Loads the training session model parameters from a contiguous buffer.

Declaration

Objective-C

- (BOOL)fromBufferWithValue:(nonnull ORTValue *)buffer
                      error:(NSError *_Nullable *_Nullable)error;

Swift

func fromBuffer(with buffer: ORTValue) throws

Parameters

`buffer`	Contiguous buffer to load the parameters from.
`error`	Optional error information set if an error occurs.

Return Value

YES if the parameters were loaded successfully, NO otherwise.


                    
                    
                    -toBufferWithTrainable:error:

Returns a contiguous buffer that holds a copy of all training state parameters.

Declaration

Objective-C

- (nullable ORTValue *)toBufferWithTrainable:(BOOL)onlyTrainable
                                       error:
                                           (NSError *_Nullable *_Nullable)error;

Swift

func toBuffer(withTrainable onlyTrainable: Bool) throws -> ORTValue

Parameters

`onlyTrainable`	If YES, returns a buffer that holds only the trainable parameters, otherwise returns a buffer that holds all the parameters.
`error`	Optional error information set if an error occurs.

Return Value

A contiguous buffer that holds a copy of all training state parameters.


                    
                    
                    -exportModelForInferenceWithOutputPath:graphOutputNames:error:

Exports the training session model that can be used for inference.

If the training session was provided with an eval model, the training session can generate an inference model if it knows the inference graph outputs. The input inference graph outputs are used to prune the eval model so that the inference model’s outputs align with the provided outputs. The exported model is saved at the path provided and can be used for inferencing with ORTSession.

Note

The method reloads the eval model from the path provided to the initializer and expects this path to be valid.

Declaration

Objective-C

- (BOOL)
    exportModelForInferenceWithOutputPath:(nonnull NSString *)inferenceModelPath
                         graphOutputNames:
                             (nonnull NSArray<NSString *> *)graphOutputNames
                                    error:(NSError *_Nullable *_Nullable)error;

Swift

func exportModelForInference(withOutputPath inferenceModelPath: String, graphOutputNames: [String]) throws

Parameters

`inferenceModelPath`	The path to the serialized the inference model.
`graphOutputNames`	The names of the outputs that are needed in the inference model.
`error`	Optional error information set if an error occurs.

Return Value

YES if the inference model was exported successfully, NO otherwise.