Training asymmetric kernels of determinantal point processes

An apparatus comprising

• a processor or a programmable circuitry;
• and
• one or more computer readable mediums collectively including instructions that, when executed by the processor or the programmable circuitry, cause the processor or the programmable circuitry to perform operations including:
• training an asymmetric kernel of a Determinantal Point Process (DPP) from a training data set by calculating an inverse matrix of a sum of the asymmetric kernel and a first identity matrix, the calculating using an inverse of a sum of the first identity matrix and a symmetric positive semidefinite matrix, a concatenated matrix made from a first matrix and a second matrix and a second identity matrix, the asymmetric kernel including the symmetric positive semidefinite matrix and a skewed-symmetric matrix, the skewed-symmetric matrix being calculated from the first matrix and the second matrix, to produce a prediction model, and
• outputting the asymmetric kernel as at least a part of the prediction model to make a prediction.