1. Joined
    26 Apr '03
    Moves
    26771
    25 Feb '10 20:25
    Originally posted by Campaigner
    Right it's quite simple what I want, if I have an recognisible image of myself and the image is 100 pixels by 100 pixels, how many other images are there of similar similar resolution? Okay we've answered that; it's 2^10000, now can we store them all (at any memory size)? We've answered that; apparently not.
    But we can store the sum total of their numeric values - can't we?
    We can even work the value of that out.
  2. Joined
    26 Apr '03
    Moves
    26771
    26 Feb '10 21:19
    The sum of all the numbers representable with n bits, is:
    2^(2n - 1) - 2^(n-1)

    which, in the case of n=10000, can be written, in binary, as 10000 "1"s followed by 9999 "0"s
  3. Joined
    06 Apr '08
    Moves
    88027
    27 Feb '10 18:58
    ...So is this number so big that it's impossble to 'work' with?
  4. Joined
    26 Apr '03
    Moves
    26771
    27 Feb '10 19:50
    Well, it's large, but not *that* large. You could probably do precise integer maths with it in various computing languages including Perl (with the BigInt module). You couldn't do maths with it very quickly at-all though, precise floating point maths would be very tricky and you would have no chance declaring an array with that many items.

    I don't know why you would really want to though.
  5. Joined
    26 Apr '03
    Moves
    26771
    27 Feb '10 22:416 edits
    The number in question is:
    99013842016898329617715360309560
    12268523863902462129693567134328
    26193179874650285213380048749877
    97755418230568752456351415700188
    46765957181087673520791351299060
    76412134467491124133079888537977
    69733480509794349863386139865970
    65759909139363201742641060008228
    30639651953551990914899676638590
    08436892410674758203057491458345
    93368093768501227293607039691363
    87412814120962196189007943489070
    84260169325045454848767983262516
    37852471514322974148867868679901
    02252949636591828315383595684670
    66296563380953348001885192652642
    28516555984550076329217386100619
    31909408897127746054258482291269
    71789278849536077319827815396941
    97098068948592342055690209436512
    94519195518348130434872340753278
    55240420796232827605902628931503
    90583844441977750876836587905672
    43283762570793007220258225773327
    57194215809521198053358377881169
    36409173068492732446198645221377
    80794109118893645965557267229221
    08489547717522889072285689477326
    06119803080757382127012537292861
    44469999377458125074730069196704
    45663030466950518124999619318913
    78888733332240486701693080971018
    19682325893654596168365571222819
    57529219498312917056066483999247
    78812466023143587388850608277194
    35781279291793924261675302874409
    38276012842852411884039355409475
    93037068971462105542782248698871
    02069051867572922520034481963379
    27498933435409282103619541937162
    47693563818785805075328757660287
    36819818703749337573413098783877
    67253503435742943906201463869113
    78831764208712349427039298762001
    02406334265380635861140121652807
    75060091004388799115271016851231
    70415833556044308463046700340289
    99322993181555898938883693044961
    73031531549829824139831939087037
    39358961858487647852320229226265
    06920766791720279541098479274260
    92605369880730275798329105506579
    95770478307271340486877520878911
    42329179154451472487677315560407
    68836332028445812172889655762280
    00999215772807106314144924336417
    25023839367498763417357047936837
    25296651196153954002295322377006
    26855666024680084106685465911132
    37445402658220076606955786935891
    16077063414003880156858436121104
    80710048376109023785809998684473
    38570052023369807270732330229276
    16108598343832571573806099575960
    63871615485023016071519076669262
    29387156652667397380761696822517
    18161459832815521164370231806282
    92128020597351008700325394669813
    80519172181165704575126955071930
    59600588231329778194171529300163
    35530945184187325828851060713846
    66445895105299784629748589780204
    28989582957085485028106434966796
    79463431307599833829718540044254
    65241153435764016066273677973708
    99538019726528636159942161170941
    62051819130879920094471956515093
    84877493408680871078556435267235
    06855798002287401781350694123411
    25519576120953066033187046066087
    71720833724497940803246459117679
    91693012952471020362290508807984
    21478850790404518048427202960229
    71000346523062086831993884157661
    32798112357875150896103862803966
    26727184687938613100519368021778
    38176163591717103398465286800020
    36839746504472906980506219787198
    68658931802731410382376033759721
    01221355181718646594292154357309
    89433482386181028645288663040332
    23156482879512492987427205066692
    10463568265483280331334137230395
    72795098322321708701861610042848
    09138434518221272166038115665106
    78690060567233406040547392526043
    42287354756879175515614504951285
    85458690927477687611366065712705
    95987341462269811881962815136762
    35415378827589851292248437185552
    46936112495225447586967848045174
    71083350808316429137394064005284
    54780417040759872574626601834808
    43145400722598878479004312165355
    93018665118677568041566425746989
    15443521041338442270473175495846
    50673662810169590218832197914024
    00963538685765755676685490428239
    10306008445404213117279762926446
    05460249031425484286715423462781
    24538091255392154072072410604456
    67951961751635201958926294344866
    57698523506991834943663638371544
    64050942615269655926261220042625
    48531323801554322704839429222233
    89849773265083274881670086631623
    98948359241895477233074087234415
    22736459453087047721234164326758
    87445123857802751130397111289686
    81229841077884597015426267752519
    52602770344378929482272743919049
    91394781265544268536331422639000
    59863752632732996252548499947385
    44099280366177745582114829330397
    84583449510785506810926861988635
    77196807081352843100623288991683
    96799399434115465783480406349662
    76739149868150732957022370119874
    57356707763626183620676427163582
    08362521989061467210313261234366
    02442882948091202772568632784953
    78555885912369830241493074638574
    15622737670032442697616098886107
    08773681883705090377520117370760
    02547213280114433332941181616357
    75753695421187005277169618868498
    69701536408870892427500083087660
    25137301777399728417964616245939
    26697839992012342203145812930882
    70269634154763392898675099219125
    94448666553651673046145264513919
    00977497972042351796015973713836
    36320345051601848105419803931793
    12703055904107940107733468766785
    90000167928285078889564247994413
    51676134038841765716777875909519
    64270141798147158705831806476182
    89340232603056685414673885616087
    96302611255921784551237445878088
    89076356142592521564577626729921
    24500554132449154929307094931689
    01424009769401775608959211036423
    07339104232309466052680882113912
    47289177033531208647684054829590
    25285096388480532577398756053867
    77375133783250089951169949236925
    70544713053528450342896608523632
    03352988592977412098401152525504
    98612482857936782385489269312554
    40538708574336986077340392311769
    34137506342718679927591507065315
    14583766587465258859093314397013
    40186520181540495661088274862606
    88833942872349604445078647219954
    48638392733846799717033758373672
    94732932538625743025927181613147
    63116901483807633702615337781183
    21104505143806702361250857603962
    82325328469100965628765041390721
    14421051644854092926861832992575
    08000267832146683794355357391896
    03347426982302840223554373273937
    87079779126428708703937517084645
    16574319746536897277045201638624
    45090924807008326811966256235769
    80652803411856383631611390356741
    41051551109302323398353402190166
    47215972795244889173185904718317
    42684612804774632161623259356172
    97218628324912696558009330353791
    61026231849771572506592931676079
    40353527537685405360046667176166
    25739394178170251969654346481698
    91347629542156843199716384925535
    01418672799430416918643381962483
    54530339939789213897024953828198
    81703420887692417649426196606130
    72365459158958177655900843540480
    0000
  6. Joined
    06 Apr '08
    Moves
    88027
    28 Feb '10 14:10
    Brilliant! Extremely Impressed.
  7. Joined
    06 Apr '08
    Moves
    88027
    28 Feb '10 14:11
    ...even if it's not!
  8. Joined
    26 Apr '03
    Moves
    26771
    28 Feb '10 23:571 edit
    I think it's right. The perl program to produce the number was a bit shorter than the number, here it is:

    use bigint;
    print 2**(2*10000 - 1) - 2**(10000-1);
  9. Joined
    02 Mar '10
    Moves
    1162
    02 Mar '10 16:41
    There are two ways to answer such a question:

    Suppose 100000000 and 000000001 are two 3x3 boards then:

    1. If you are asked to count them as two different boards, then the correct answer is 2^(100x100) = 2^10000

    2. If you are asked to count all symmetrically identical (identical by rotations and reflections) boards as a single board, then the correct answer is a bit more complicated and involves groups theory (Burnside's Lemma).
  10. Joined
    06 Apr '08
    Moves
    88027
    19 Mar '10 12:57
    Why should it involve a theory when you're going from all white squares to all black squares and everything in between. Imagine it like a chessboard, but all the files in one line of 1000 squares and instead of black have a 0 and instead of white having a 1, now doesn't that make it all easier? - or does it?
  11. Joined
    02 Mar '10
    Moves
    1162
    28 Mar '10 23:571 edit
    No, that does not make it any easier.
    If you take symmetry into account, then you have much less options to count.
    Not something you'd be willing to count by hand though.
  12. Joined
    06 Apr '08
    Moves
    88027
    29 Mar '10 23:19
    ...thing is, I don't want to do anything spectacular with these numbers, just to create one for one instance then to recreate it in an other instance.
  13. Joined
    06 Apr '08
    Moves
    88027
    10 Apr '10 18:32
    How then to suit, if it was an actual chessboard? I am now going to create a 64 x 64 pixel image/photograph/picture. Now - how many other pictures like this are out there?
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