GradientCollector (Deep Java Library 0.23.0 API specification)

All Superinterfaces:

java.lang.AutoCloseable
```
public interface GradientCollector
extends java.lang.AutoCloseable
```
An interface that provides a mechanism to collect gradients during training.
The GradientCollector should be opened with a try-with-resources. All operations performed within the try-with-resources are recorded and the variables marked. When backward function is called, gradients are collected w.r.t previously marked variables.
The typical behavior is to open up a gradient collector during each batch and close it during the end of the batch. In this way, the gradient is reset between batches. If the gradient collector is left open for multiple calls to backwards, the gradients collected are accumulated and added together.
Due to limitations in most engines, the gradient collectors are global. This means that only one can be used at a time. If multiple are opened, an error will be thrown.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`backward(NDArray target)`	Calculate the gradient w.r.t previously marked variable (head).
`void`	`close()`
`void`	`zeroGradients()`	Sets all the gradients within the engine to zero.

- Method Detail
  - backward
```
void backward(NDArray target)
```
    Calculate the gradient w.r.t previously marked variable (head).
    
    Parameters:
    
    target - the target NDArray to calculate the gradient w.r.t head
  - zeroGradients
```
void zeroGradients()
```
    Sets all the gradients within the engine to zero.
  - close
```
void close()
```
    Specified by:
    
    close in interface java.lang.AutoCloseable