Log of a computation of 9^(9^9) at 25-October-2010 on a machine with 4GB RAM (taking 81sec CPU time). % cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 16 model : 4 model name : AMD Phenom(tm) II X4 945 Processor stepping : 3 cpu MHz : 800.000 cache size : 512 KB ----============== HFLOAT version 25-October-2010 ===============---- author: Joerg Arndt, email: arndt (AT) jjj.de compiler used: GNU C 4.5.0 20100604 [gcc-4_5-branch revision 160292] compilation date: Oct 25 2010, 14:36:34 compilation flags were: -O2 -fomit-frame-pointer -ffast-math HFLOAT is online at http://www.jjj.de/hfloat/ ----===========================================================---- n = 9 ... computing n**(n**n) = 9 ** 387420489 hfloat: radix = 1000 hfloat: default precision is 123231034 LIMBs hfloat: = 3.69693e+08 dec / 3.07023e+08 hex digits = 1.22809e+09 bits hfloat: iterations for inverse n-th root are NOT checked fxtmult: FFT multiplications ARE checked via sum of digit test fxtmult: swapfile1 is "/tmp/massstorage1.bin" fxtmult: swapfile2 is "/tmp/massstorage2.bin" fxtmult: max swapfile size will be (2x) 2048 MB workspace: size = 2147483648 bytes =2048 MB =256 Mdoubles workspace: #doubles = 268435456 workspace: extra (pad) doubles = 0 workspace: noswap size = 2147483648 bytes =2048 MB =256 Mdoubles workspace: cache size = 262144 bytes =256 kB =32 kdoubles 1 [ 0] -- S --> 1 [ 0] t*t==+.81000000*10^2 1 [ 0] -- S --> 2 [ 1] t*t==+.6561000*10^4 1 [ 0], 2 [ 1] -- M --> 2 [ 1] a*c==+.81000000*10^2 2 [ 1] -- S --> 4 [ 2] t*t==+.3486784401*10^10 1 [ 0], 4 [ 2] -- M --> 4 [ 2] a*c==+.59049000*10^5 4 [ 2] -- S --> 7 [ 3] t*t==+.984770902183611232881*10^21 1 [ 0], 7 [ 3] -- M --> 8 [ 3] a*c==+.31381059609*10^11 8 [ 3] -- S --> 15 [ 4] t*t==+.78551672112789411833022*10^44 15 [ 4] -- S --> 30 [ 5] t*t==+.6170365191715177779482*10^88 30 [ 5] -- S --> 59 [ 6] t*t==+.38073406599130282633302*10^176 59 [ 6] -- S. --> 118 [ 7] t*t==+.1449584290062697354142*10^352 1 [ 0], 118 [ 7] -- M --> 118 [ 7] a*c==+.38073406599130282633302*10^176 118 [ 7] -- S. --> 235 [ 8] t*t==+.170204863733722518233708*10^705 235 [ 8] -- S. --> 470 [ 9] t*t==+.28969695638615050930315*10^1409 1 [ 0], 470 [ 9] -- M --> 470 [ 9] a*c==+.170204863733722518233708*10^705 470 [ 9] -- S. --> 940 [10] t*t==+.67978704496913344187598*10^2819 1 [ 0], 940 [10] -- M --> 940 [10] a*c==+.260727260747535458372839*10^1410 940 [10] -- S. --> 1880 [11] t*t==+.374309445471371988385728*10^5640 1 [ 0], 1880 [11] -- M --> 1881 [11] a*c==+.611808340472220097688384*10^2820 1881 [11] -- S. --> 3761 [12] t*t==+.11348712438495965995513*10^11282 1 [ 0], 3761 [12] -- M --> 3761 [12] a*c==+.3368785009242347895471*10^5641 3761 [12] -- S. --> 7522 [13] t*t==+.10432255194945517436245*10^22565 7522 [13] -- S. --> 15043 [14] t*t==+.108831948452467736007466*10^45129 15043 [14] -- S. --> 30086 [15] t*t==+.11844393003960594438411*10^90257 1 [ 0], 30086 [15] -- M --> 30086 [15] a*c==+.108831948452467736007466*10^45129 30086 [15] -- S: --> 60172 [16] t*t==+.11363461296213924602100*10^180515 60172 [16] -- S: --> 120343 [17] t*t==+.129128252630551847488515*10^361029 120343 [17] -- S: --> 240686 [18] t*t==+.16674105627419620120720*10^722057 240686 [18] -- S: --> 481371 [19] t*t==+.278025798474346643561406*10^1444113 1 [ 0], 481371 [19] -- M --> 481372 [19] a*c==+.16674105627419620120720*10^722057 481372 [19] -- S: --> 962743 [20] t*t==+.6261165914001139007199*10^2888227 962743 [20] -- S: --> 1925485 [21] t*t==+.39202198602649718422112*10^5776454 1 [ 0], 1925485 [21] -- M --> 1925485 [21] a*c==+.6261165914001139007199*10^2888227 1925485 [21] -- S: --> 3850970 [22] t*t==+.124481802397808914387043*10^11552910 3850970 [22] -- S: --> 7701940 [23] t*t==+.15495719128207145187377*10^23105819 7701940 [23] -- S: --> 15403879 [24] t*t==+.240117311300284807668685*10^46211637 1 [ 0], 15403879 [24] -- M --> 15403880 [24] a*c==+.15495719128207145187377*10^23105819 15403880 [24] -- S: --> 30807759 [25] t*t==+.4670162178072308457656*10^92423275 30807759 [25] -- S: --> 61615517 [26] t*t==+.21810414769497088132195*10^184846550 61615517 [26] -- S: --> 123231033 [27] t*t==+.475694192417496720041096*10^369693099 1 [ 0], 123231033 [27] -- M --> 123231034 [27] a*c==+.21810414769497088132195*10^184846550 computation finished. n**(n**n)== +.4281247731757470480369871159305635213390554822*10^369693100 prec=123231034 LIMBs == 3.69693e+08 dec.dig. saving result to file "/tmp/result.txt" ... done. hfloat: radix = 1000 hfloat: default precision is 123231034 LIMBs hfloat: = 3.69693e+08 dec / 3.07023e+08 hex digits = 1.22809e+09 bits hfloat: iterations for inverse n-th root are NOT checked fxtmult: FFT multiplications ARE checked via sum of digit test fxtmult: swapfile1 is "/tmp/massstorage1.bin" fxtmult: swapfile2 is "/tmp/massstorage2.bin" fxtmult: max swapfile size will be (2x) 2048 MB workspace: size = 2147483648 bytes =2048 MB =256 Mdoubles workspace: #doubles = 268435456 workspace: extra (pad) doubles = 0 workspace: noswap size = 2147483648 bytes =2048 MB =256 Mdoubles workspace: cache size = 262144 bytes =256 kB =32 kdoubles hfdata: bytes currently allocated: 492924138 hfdata: max bytes allocated: 492924138 (plus workspace) fxtmult: work was=665.6 times length 2^20 real FFTs fxtmult: == 2.03166 full prec real FFTs fxtmult: == 0.677219 full prec mults ./ex999 9 80.79s user 1.44s system 98% cpu 1:23.42 total