You have reached the maximum value that can be stored accurately in a floating point number. That is what the error message is telling you. I get 21 warnings and this says that at 8^20 I am now truncating digits in the variable. You only have about 54 bits in the floating point number and you exceed this about 8^19.
> a=1:40; > 8^a %% 41 [1] 8 23 20 37 9 31 2 16 5 40 33 18 21 4 32 10 39 25 36 1 8 23 20 37 9 31 2 16 5 40 33 [32] 18 21 4 32 10 0 0 0 0 There were 21 warnings (use warnings() to see them) > warnings() Warning messages: 1: probable complete loss of accuracy in modulus 2: probable complete loss of accuracy in modulus 3: probable complete loss of accuracy in modulus 4: probable complete loss of accuracy in modulus 5: probable complete loss of accuracy in modulus 6: probable complete loss of accuracy in modulus 7: probable complete loss of accuracy in modulus 8: probable complete loss of accuracy in modulus 9: probable complete loss of accuracy in modulus 10: probable complete loss of accuracy in modulus 11: probable complete loss of accuracy in modulus 12: probable complete loss of accuracy in modulus 13: probable complete loss of accuracy in modulus 14: probable complete loss of accuracy in modulus 15: probable complete loss of accuracy in modulus 16: probable complete loss of accuracy in modulus 17: probable complete loss of accuracy in modulus 18: probable complete loss of accuracy in modulus 19: probable complete loss of accuracy in modulus 20: probable complete loss of accuracy in modulus 21: probable complete loss of accuracy in modulus > > 8^35 [1] 4.056482e+31 > 8^36 [1] 3.245186e+32 > 8^19 [1] 1.441152e+17 > 8^19%%41 [1] 36 > 8^20 [1] 1.152922e+18 > 8^20%%41 [1] 1 Warning message: probable complete loss of accuracy in modulus > On 1/30/06, Ionut Florescu <[EMAIL PROTECTED]> wrote: > > I am a statistician and I come up to an interesting problem in > cryptography. I would like to use R since there are some statistical > procedures that I need to use. > However, I run into a problem when using the modulus operator %%. > > I am using R 2.2.1 and when I calculate modulus for large numbers (that > I need with my problem) R gives me warnings. For instance if one does: > a=1:40; > 8^a %% 41 > one obtains zeros which is not possible since 8 to any power is not a > multiple of 41. > In addition when working with numbers larger that this and with the mod > operator R crashes randomly. > > I believe this is because R stores large integers as real numbers thus > there may be lack of accuracy when applying the modulus operator and > converting back to integers. > > So my question is this: Is it possible to increase the size of memory > used for storing integers? Say from 32 bits to 512 bits (Typical size of > integers in cryptography). > > Thank you, any help would be greatly appreciated. > Ionut Florescu > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > -- Jim Holtman Cincinnati, OH +1 513 247 0281 What the problem you are trying to solve? [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
