# The Multiphoton Boson Sampling Machine Doesn't Beat Early Classical Computers for Five-boson Sampling. (arXiv:1802.02779v1 [cs.CC])

An ignored algorithm called Store-reuse for calculating the permanent of an n

* n matrix is considered. It utilizes computer storages sufficiently, and uses

stored data repetitively. The analysis manifests that the numbers of

multiplications and additions taken by the Store-reuse algorithm are

respectively far smaller than those taken by the famous Ryser's algorithm. As

to the 5-boson sampling, the running times of the Store-reuse algorithm for a

related permanent on ENIAC and TRADIC are each lower than the that of the

sampling operation on the multiphoton boson sampling machine (shortly MPBSM),

and thus MPBSM does not beat the early classical computers. However, this does

not mean that a quantum boson sampling machine will be beaten by a classical

computer when n gets large enough. On a computer, people can design an

algorithm that exchanges space for time while on MPBSM, people can not do so,

which is the greatest difference between a universal computer and MPBSM. This

difference is right the reason why MPBSM may not be called a (photonic) quantum

computer.