Constant order compression is a new compression method based on permutation and combination . But there is huge computing quantity and the speed of this method is too slow. How to compute ordinal number is an important problem in constant order compression. The optimization on ordinal number computing is studied and the computing speed is improved in this paper. Firstly, the theory of constant order compression method is expatiated. Then, s ome relative formulas of the factorial method and proportion method are deduced to compute ordinal number. The consumption time of the three different computing methods above is compared, the results of which show that proportion method has more preponderance to compute ordinal number. Proportion method improves speed on computing ordinal number efficiently. Moreover, proportion method is optimized to group proportion computing. Group proportion method can advance computing speed double. All these work enhance the speed of ordinal number computed. Further, the efficiency of constant order compression technology is advanced. All these make constant order compression technology go ahead quickly to utility.
[1]
C. E. SHANNON,et al.
A mathematical theory of communication
,
1948,
MOCO.
[2]
Jorma Rissanen,et al.
Compression of Black-White Images with Arithmetic Coding
,
1981,
IEEE Trans. Commun..
[3]
Abraham Lempel,et al.
Compression of individual sequences via variable-rate coding
,
1978,
IEEE Trans. Inf. Theory.
[4]
Daniel S. Hirschberg,et al.
Data compression
,
1987,
CSUR.
[5]
D. Huffman.
A Method for the Construction of Minimum-Redundancy Codes
,
1952
.
[6]
Abraham Lempel,et al.
A universal algorithm for sequential data compression
,
1977,
IEEE Trans. Inf. Theory.
[7]
Terry A. Welch,et al.
A Technique for High-Performance Data Compression
,
1984,
Computer.
[8]
Ma Yan-bin.
Study on frequency table of stochastic subsection file in constant grade compression method
,
2008
.
[9]
Chen Li-yan.
Compression method with constant degree based on permutation and combination
,
2008
.