Update on LZMA Compression Memory Usage

LZMA2 Style Dictionary Sizes Now in Effect

lrzip-next Version 0.7.50 will mark a departure from the way Dictionary Sizes can be specified. lrzip-next will still automatically determine lzma dictionary sizes. But if the --dictsize= option is used, instead of 12-30, the options will range from 0-40. The table below will show the new mappings.

Dictionary Code	2s Exponent	2*2^n Dict Size	lrzip-next Level Default Dict Size	Per Thread Memory Overhead	Dictionary Code	3*2^n Dict Size	Per Thread Memory Overhead
0	11	4,096		6,354,944	1	6,144	6,378,496
2	12	8,192		6,402,048	3	12,288	6,449,152
4	13	16,384		6,496,256	5	24,576	6,590,464
6	14	32,768		6,684,672	7	49,152	6,873,088
8	15	65,536	1	7,061,504	9	98,304	7,438,336
10	16	131,072		7,815,168	11	196,608	8,568,832
12	17	262,144	2	9,322,496	13	393,216	10,829,824
14	18	524,288		12,337,152	15	786,432	15,351,808
16	19	1,048,576	3	18,366,464	17	1,572,864	24,395,776
18	20	2,097,152		30,425,088	19	3,145,728	42,483,712
20	21	4,194,304	4	54,542,336	21	6,291,456	78,659,584
22	22	8,388,608		102,776,832	23	12,582,912	151,011,328
24	23	16,777,216	5	199,245,824	25	25,165,824	295,714,816
26	24	33,554,432	6,7	392,183,808	27	50,331,648	585,121,792
28	25	67,108,864	8	778,059,776	29	100,663,296	1,163,935,744
30	26	134,217,728	9	1,549,811,712	31	201,326,592	2,321,563,648
32	27	268,435,456		3,093,315,584	33	402,653,184	4,636,819,456
34	28	536,870,912		6,180,323,328	35	805,306,368	9,267,331,072
36	29	1,073,741,824		12,354,338,816	37	1,610,612,736	18,528,354,304
38	30	2,147,483,648		24,702,369,792	39	3,221,225,472	37,050,400,768
40	31	4,294,967,295		49,398,431,733

Memory Overhead per thread is computed as follows:
Dictionary Size * 11.5 + 6MB + 16KB
Dictionary Size will be automatically reduced if sufficient memory is not available