1. A computing apparatus comprising: a memory configured to store N first vectors in a d-dimensional binary vector space consisting of binary values (0 or 1), wherein each of the N first vectors is represented by d binary elements, wherein N is an integer equal to or larger than 2, and d is an integer equal to or larger than 1; and a processor configured to: acquire a second vector in the d-dimensional binary vector space, the second vector represented by d binary elements; extract M first vectors having a distance from the second vector satisfying a first condition out of the N first vectors, and calculate a distribution of distances of the M first vectors from the second vector, wherein M is an integer, larger than zero, and smaller than N; acquire a first kernel function per a first distance between the M first vectors and the second vector in a first range; generate a second kernel function based on the distribution and the first kernel functions; and calculate an occurrence probability of the second vector in the N first vectors based on the second kernel function.