A system for training a neural network includes a first set of neural network units and a second set of neural networking units. Each neural network unit in the first set is configured to compute parameter update data for one of a plurality of instances of a first portion of the neural network. Each neural network unit in the first set includes a communication interface for communicating its parameter update data for combination with parameter update data from another neural network unit in the first set. Each neural network unit in the second set is configured to compute parameter update data for one of a plurality of instances of a second portion of the neural network. Each neural network unit in the second set includes a communication interface for communicating its parameter update data for combination with parameter update data from another neural network unit in the second set.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A system for training a neural network having a plurality of interconnected layers, the system comprising: a first set of neural network units, each neural network unit in the first set configured to compute parameter update data for one of a plurality of instances of a first portion of the neural network, each neural network unit in the first set comprising a communication interface for communicating its parameter update data for combination with parameter update data from another neural network unit in the first set; and a second set of neural network units, each neural network unit in the second set configured to compute parameter update data for one of a plurality of instances of a second portion of the neural network, each neural network unit in the second set comprising a communication interface for communicating its parameter update data for combination with parameter update data from another neural network unit in the second set. 2. The system of claim 1, wherein each neural network unit in the first set is configured to communicate its respective parameter update data to a central node via its respective communication interface. 3. The system of claim 1, wherein at least one of the neural network units in the first set is configured to communicate its parameter update data to another neural network unit in the first set via its communication interface. 4. The system of claim 2, wherein the central node comprises or is part of one of the neural network units in the first set. 5. The system of claim 2, where each neural network unit in the second set is configured to communicate its respective parameter update data to a second central node via its respective communication interface. 6. The system of claim 1, wherein the neural network units in the first set are arranged in a reduction tree arrangement to communicate parameter update data to a central node. 7. The system of claim 1, where each neural network unit in the first set is configured to compute input data for a respective neural network unit in the second set; the respective neural network unit in the second set configured to compute the parameter update data for the corresponding instance of the second portion of the neural network based on the input data. 8. The system of claim 7, wherein at least one neural network unit in the first set initiates communication of its respective parameter update data before the neural network units in the second set initiate communication of their parameter update data. 9. The system of claim 1, wherein the first portion of the neural network is a single layer of the neural network. 10. The system of claim 1, wherein the first portion of the neural network is at least a portion of two or more layers of the neural network. 11. A method for training a neural network with an architecture having a plurality of instances of the neural network, the method comprising: for each neural network unit in a first set of neural network units configured to compute parameter update data for one of a plurality of instances of a first portion of the neural network, communicating the parameter update data generated by the neural network unit for combination with parameter update data from another neural network unit in the first set; and for each neural network unit in a second set of neural network units configured to compute parameter update data for one of a plurality of instances of a second portion of the neural network, communicating the parameter update data generated by the neural network unit for combination with parameter update data from another neural network unit in the second set. 12. The method of claim 11, wherein the parameter update data computed by each of the neural network units in the first set is communicated to a central node via each neural network units' respective communication interface. 13. The method of claim 11, wherein the parameter update data computed by at least one of the neural network units in the first set is communicated to a another neural network unit in the first set via its communication interface. 14. The method of claim 12, wherein the central node comprises or is part of one of the neural network units in the first set. 15. The method of claim 12, wherein the parameter update data computed by each of the neural network units in the second set is communicated to a second central node via each neural network units' respective communication interface. 16. The method of claim 11, comprising: communicating the parameter update data generated by the neural network units in the first set in a reduction tree arrangement to communicate the parameter update data to a central node. 17. The method of claim 11, where each neural network unit in the first set is configured to compute input data for a respective neural network unit in the second set; the respective neural network unit in the second set configured to compute the parameter update data for the corresponding instance of the second portion of the neural network based on the input data. 18. The method of claim 17, comprising: initiating communication of parameter update data for at least one neural network unit in the first set before communicating the parameter update data generated by the neural network units in the second set. 19. The method of claim 11, wherein the first portion of the neural network is a single layer of the neural network. 20. A non-transitory, computer-readable medium or media having stored thereon computer-readable instructions which when executed by at least one processor configure the at least one processor to: for each neural network unit in a first set of neural network units configured to compute parameter update data for one of a plurality of instances of a first portion of a neural network, communicate the parameter update data generated by the neural network unit for combination with parameter update data from another neural network unit in the first set; and for each neural network unit in a second set of neural network units configured to compute parameter update data for one of a plurality of instances of a second portion of the neural network, communicate the parameter update data generated by the neural network unit for combination with parameter update data from another neural network unit in the second set.