Multiple machine learning models can be jointly trained in parallel. An example process for jointly training multiple machine learning models includes providing a set of machine learning models that are to learn a respective task, the set of machine learning models including a first machine learning model and a second machine learning model. The process can initiate training of the first machine learning model to learn a task using training data. During the training of the first machine learning model, information can be passed between the first machine learning model and the second machine learning model. Such passing of information (or “transfer of knowledge”) between the machine learning models can be accomplished via the formulation, and optimization, of an objective function that comprises model parameters that are based on the multiple machine learning models in the set.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A computer-implemented method comprising: providing a set of machine learning models that are to learn a respective task, the set of machine learning models including a first machine learning model and a second machine learning model; initiating training of the first machine learning model to learn a first task using training data; and during the training of the first machine learning model, passing information between the first machine learning model and the second machine learning model. 2. The computer-implemented method of claim 1, wherein passing the information comprises providing the second machine learning model access to output from the first machine learning model, the method further comprising training the second machine learning model to learn the first task, or a second task that is related to the first task, using the output from the first machine learning model. 3. The computer-implemented method of claim 2, wherein the output from the first machine learning model comprises at least one of probability outputs, logits, or unnormalized probabilities. 4. The computer-implemented method of claim 1, wherein: the first machine learning model is trained to learn the first task using a set of features from the training data; and passing the information comprises providing the second machine learning model access to output from the first machine learning model, the method further comprising training the second machine learning model to learn the first task, or a second task that is related to the first task, using the output from the first machine learning model and a subset of features from the set of features. 5. The computer-implemented method of claim 1, wherein: the set of machine learning models further includes a plurality of teacher machine learning models; and the first machine learning model is one of the plurality of teacher machine learning models, the method further comprising training the first machine learning model and at least one other teacher machine learning model of the plurality of teacher machine learning models in parallel with each other and in parallel with the second machine learning model. 6. The computer-implemented method of claim 5, wherein the first machine learning model is trained from a first portion of the training data and the at least one other teacher machine learning model is trained from a second portion of the training data that is different than the first portion. 7. The computer-implemented method of claim 1, wherein: the set of machine learning models further includes a plurality of student machine learning models; and the second machine learning model is one of the plurality of student machine learning models, the method further comprising training the second machine learning model and at least one other student machine learning model of the plurality of student machine learning models in parallel with each other and in parallel with the first machine learning model. 8. The computer-implemented method of claim 7, further comprising passing information between individual pairings of the plurality of student machine learning models during the training of the first machine learning model and during the training of at least some of the plurality of student machine learning models. 9. The computer-implemented method of claim 1, wherein the second machine learning model is trained and stored as a trained second machine learning model in a smaller amount of memory than an amount of memory to store the first machine learning model after the first machine learning model is trained. 10. A system comprising: one or more processors; and memory storing computer-executable instructions that, when executed by the one or more processors, cause performance of operations comprising: initiating training of a first machine learning model to learn a first task using training data; and during the training of the first machine learning model: initiating training of a second machine learning model to learn the first task or a second task that is related to the first task; and passing information between the first machine learning model and the second machine learning model. 11. The system of claim 10, wherein: the first machine learning model is trained to learn the first task using a set of features from the training data; and passing the information comprises providing the second machine learning model access to output from the first machine learning model, the operations further comprising training the second machine learning model to learn the first task or the second task using the output from the first machine learning model and a subset of features from the set of features. 12. The system of claim 11, wherein the output from the first machine learning model is based on processing unlabeled input data through the first machine learning model. 13. The system of claim 10, wherein the first machine learning model is one of a plurality of teacher machine learning models in a set of machine learning models that includes the plurality of teacher machine learning models and the second machine learning model, the operations further comprising training the first machine learning model and at least one other teacher machine learning model of the plurality of teacher machine learning models in parallel with each other and in parallel with the second machine learning model. 14. The system of claim 10, wherein the second machine learning model is one of a plurality of student machine learning models in a set of machine learning models that includes the plurality of student machine learning models and the first machine learning model, the operations further comprising training the second machine learning model and at least one other student machine learning model of the plurality of student machine learning models in parallel with each other and in parallel with the first machine learning model. 15. The system of claim 14, wherein the second machine learning model is trained and stored in a larger amount of memory than an amount of memory to store the at least one other student machine learning model. 16. A computer-implemented method for training a set of machine learning models, the method comprising: generating an objective function that includes at least one term that is a function of a first output of a first machine learning model and second output of a second machine learning model; and optimizing the objective function to train the first machine learning model and the second machine learning model. 17. The computer-implemented method of claim 16, wherein the first output comprises at least one of probability outputs, logits, or unnormalized probabilities. 18. The computer-implemented method of claim 16, wherein the first machine learning model is to learn a first task, and the second machine learning model is to learn the first task, or a second task that is related to the first task. 19. The computer-implemented method of claim 16, wherein: the set of machine learning models further includes a plurality of teacher machine learning models, the plurality of teacher machine learning models including: the first machine learning model; and a third machine learning model; the at least one term included in the objective function is further a function of a third output of the third machine learning model; and optimizing the objective function trains the first machine learning model and third machine learning model in parallel with each other and in parallel with the second machine learning model. 20. The computer-implemented method of claim 19, wherein the first machine learning model is trained from a first portion of training data and the third machine learning model is trained from a second portion of the training data that is different than the first portion.