Minimac4 is a lower memory and more computationally efficient implementation of "minimac2/3". It is an algorithm for genotypic imputation that works on phased genotypes (say from MaCH).

Minimac4 is designed to handle very large reference panels in a more computationally efficient way with no loss of accuracy. This algorithm analyzes only the unique sets of haplotypes in small genomic segments, thereby saving on time\-complexity, computational memory but no loss in degree of accuracy.