Asynchronous stochastic gradient descent

1. A computer-implemented method for asynchronous stochastic gradient descent, the method comprising:

computing, by a generator processor on each of a plurality of learners, a gradient for a mini-batch using a current weight at each of the plurality of learners, the current weight being uniquely identified by a weight index of each of the plurality of learners, wherein the plurality of learners are arranged in a peer-to-peer arrangement without a parameter server;

generating, by the generator processor on each of the plurality of learners, a plurality of triples, wherein each of the triples comprises the gradient, the weight index of the current weights used to compute the gradient, and a mass of the gradient, the mass equaling a number of mini-batches used to generate the gradient times a number of observations in the mini-batch;

performing, by a reconciler processor on each of the plurality of learners, an allreduce operation on the plurality of triples to obtain an allreduced triple sequence; and

updating, by the reconciler processor on each of the plurality of learners, the current weight at each of the plurality of learners to a new current weight using the allreduced triple sequence, wherein the new current weight becomes the current weight for a next processing batch to be computed by the generator processor.

2. The computer-implemented method of claim 1 , wherein the generator processor and the reconciler processor execute simultaneously.

3. The computer-implemented method of claim 2 , further comprising:

communicating the plurality of triples from the generator processor to the reconciler processor using a non-blocking to-Learner buffer; and

communicating the current weight with index from the reconciler processor to the generator processor through the use of a non-blocking from-Learner buffer.

4. The computer-implemented method of claim 3 , further comprising:

performing a summing-in of a new gradient into an existing gradient when it is determined that the non-blocking to-Learner buffer is full.

5. The computer-implemented method of claim 1 , wherein performing the allreduce operation comprises performing a summation function on the plurality of triples to sum the masses of the plurality of triples.

6. The computer-implemented method of claim 1 , wherein performing the allreduce operation comprises performing a minimum function on the plurality of triples to determine a minimum of the weight indices of the plurality of triples.

7. The computer-implemented method of claim 1 , wherein the allreduce operation is performed in stages across subsets of the plurality of learners.

8. The computer-implemented method of claim 1 , wherein the allreduced triple sequence comprises at least one triple, and wherein a mass associated with each of the at least one triples is equal to a given target mass.

9. The computer-implemented method of claim 1 , wherein at least one of the generator processor and the reconciler processor are multi-threaded processors.

10. A system for Asynchronous stochastic gradient descent, the system comprising:

a processor in communication with one or more types of memory, the processor configured to:

compute, by a generator processor on each of a plurality of learners, a gradient for a mini-batch using a current weight at each of the plurality of learners, the current weight being uniquely identified by a weight index of each of the plurality of learners, wherein the plurality of learners are arranged in a peer-to-peer arrangement without a parameter server;

generate, by the generator processor on each of the plurality of learners, a plurality of triples, wherein each of the triples comprises the gradient, the weight index of the current weights used to compute the gradient, and a mass of the gradient, the mass equaling a number of mini-batches used to generate the gradient times a number of observations in the mini-batch;

perform, by a reconciler processor on each of the plurality of learners, an allreduce operation on the plurality of triples to obtain an allreduced triple sequence; and

update by the reconciler processor on each of the plurality of learners, the current weight at each of the plurality of learners to a new current weight using the allreduced triple sequence, wherein the new current weight becomes the current weight for a next processing batch to be computed by the generator processor.

11. The system of claim 10 , wherein the generator processor and the reconciler processor execute simultaneously.

12. The system of claim 11 , wherein the processor is further configured to:

communicate the plurality of triples from the generator processor to the reconciler processor using a non-blocking to-Learner buffer; and

communicate the current weight with index from the reconciler processor to the generator processor through the use of a non-blocking from-Learner buffer.

13. The system of claim 12 , wherein the processor is further configured to:

perform a summing-in of a new gradient into an existing gradient when it is determined that the non-blocking to-Learner buffer is full.

14. The system of claim 10 , wherein performing the allreduce operation comprises performing a summation function on the plurality of triples to sum the masses of the plurality of triples.

15. The system of claim 10 , wherein performing the allreduce operation comprises performing a minimum function on the plurality of triples to determine a minimum of the weight indices of the plurality of triples.

16. The system of claim 10 , wherein the allreduce operation is performed in stages across subsets of the plurality of learners.

17. The system of claim 10 , wherein the allreduced triple sequence comprises at least one triple, and wherein a mass associated with each of the at least one triples is equal to a given target mass.

18. A computer program product for asynchronous stochastic gradient descent, the computer program product comprising:

a non-transitory storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:

computing, by a generator processor on each of a plurality of learners, a gradient for a mini-batch using a current weight at each of the plurality of learners, the current weight being uniquely identified by a weight index of each of the plurality of learners, wherein the plurality of learners are arranged in a peer-to-peer arrangement without a parameter server;

generating, by the generator processor on each of the plurality of learners, a plurality of triples, wherein each of the triples comprises the gradient, the weight index of the current weights used to compute the gradient, and a mass of the gradient, the mass equaling a number of mini-batches used to generate the gradient times a number of observations in the mini-batch;

performing, by a reconciler processor on each of the plurality of learners, an allreduce operation on the plurality of triples to obtain an allreduced triple sequence; and

updating, by the reconciler processor on each of the plurality of learners, the current weight at each of the plurality of learners to a new current weight using the allreduced triple sequence, wherein the new current weight becomes the current weight for a next processing batch to be computed by the generator processor.