Methods for transforming categorical source data distributions into target data distributions for use by machine learning model training

A method, comprising:

• identifying, by a machine learning system, a target distribution of categorical source data comprising a plurality of categories of data items, wherein:
• the categorical source data has an initial distribution of the data items within the plurality of categories;
• and
• the target distribution is different from the initial distribution;
• respectively indexing, by the machine learning system, data items of the plurality of categories of data items into respective indexes;
• determining, by the machine learning system, stop criteria for generating the target distribution;
• sampling, by the machine learning system, the data items from the respective categories of data items according to the target distribution and the stop criteria using the respective indexes;
• determining that the stop criteria have been satisfied;
• and
• storing, by the machine learning system, the target distribution of categorical source data in a target location.

One or more non-transitory, computer-readable storage media, storing program instructions that when executed on or across one or more computing devices cause the one or more computing devices to:

• identify, by a machine learning system, a target distribution of categorical source data comprising a plurality of categories of data items, wherein:
• the categorical source data has an initial distribution of the data items within the plurality of categories;
• and
• the target distribution is different from the initial distribution;
• respectively index data items of the plurality of categories of data items into respective indexes;
• determine stop criteria for generating the target distribution;
• sample the data items from the respective categories of data items according to the target distribution and the stop criteria using the respective indexes;
• determine that the stop criteria have been satisfied;
• and
• store the target distribution of categorical source data in a target location.