arbitrary-precision

问题 Is there any standard way to use integers of arbitrary length in Perl? I am working on code that generates x64 assembly for tests, and I'm tired of manipulating 32 bits at a time. I'm using Perl 5.10.0, for what it's worth. 回答1: If you only want to use big integers, you can use the bigint , which you can scope to a file: use bigint; or just a limited scope: { use bigint; ...; } If you need big floating point numbers as well as big integers, you can use the bignum pragma in the same way.

问题 I need to convert a large (too large for the built-in data types) hex string to a string with it's decimal representation. For example: std::string sHex = "07AA17C660F3DD1D2A1B48F1B746C148"; std::string sDec; // should end up with: "10187768649047767717933300899576725832" I'm currently using the c++ BigInt Class which offers a very easy way to achieve this (but is GPL only): BigInt::Vin vbiTemp(sHex, 16); sDec = vbiTemp.toStrDec(); Is there simple way to do this conversion without a 3rd party

问题 How do hig-performance native big-integer libraries on x86-64 represent a big integer in memory? (or does it vary? Is there a most common way?) Naively I was thinking about storing them as 0-terminated strings of numbers in base 2 64 . For example suppose X is in memory as: [8 bytes] Dn . . [8 bytes] D2 [8 bytes] D1 [8 bytes] D0 [8 bytes] 0 Let B = 2 64 Then X = D n * B n + ... + D 2 * B 2 + D 1 * B 1 + D 0 The empty string (i.e. 8 bytes of zero) means zero. Is this a reasonable way? What are

问题 What class should I use for representation of money to avoid most rounding errors? Should I use Decimal , or a simple built-in number ? Is there any existing Money class with support for currency conversion that I could use? Any pitfalls that I should avoid? 回答1: I assume that you talking about Python. http://code.google.com/p/python-money/ "Primitives for working with money and currencies in Python" - the title is self explanatory :) 回答2: Never use a floating point number to represent money.

问题 What class should I use for representation of money to avoid most rounding errors? Should I use Decimal , or a simple built-in number ? Is there any existing Money class with support for currency conversion that I could use? Any pitfalls that I should avoid? 回答1: I assume that you talking about Python. http://code.google.com/p/python-money/ "Primitives for working with money and currencies in Python" - the title is self explanatory :) 回答2: Never use a floating point number to represent money.

问题 I have a numpy 2d array [medium/large sized - say 500x500]. I want to find the eigenvalues of the element-wise exponent of it. The problem is that some of the values are quite negative (-800,-1000, etc), and their exponents underflow (meaning they are so close to zero, so that numpy treats them as zero). Is there anyway to use arbitrary precision in numpy? The way I dream it: import numpy as np np.set_precision('arbitrary') # <--- Missing part a = np.array([[-800.21,-600.00],[-600.00,-1000.48

问题 I need to do bit operations on representations of arbitrary precision numbers in Objective C. So far I have been using NSData objects to hold the numbers - is there a way to bit shift the content of those? If not, is there a different way to achieve this? 回答1: Using NSMutableData you can fetch the byte in a char , shift your bits and replace it with -replaceBytesInRange:withBytes: . I don't see any other solution except for writing your own date holder class using a char * buffer to hold the

问题 So of course I know there are simple solutions to this such as using the GMP library or numerous other arbitrary-precision libraries. This is for class work so I am not allowed to take any of these routes. After we build up all our operations we are leading up to be able to do a RSA encryption scheme. I am using vectors to store n-bit numbers represented in binary. I have conversions to decimal later but I must operate on the binary and only convert for display. I have successfully

问题 I need a BSD-like licensed C(++) multiprecision library with complex numbers support so I tried boost. The following code fails: #include <boost/multiprecision/cpp_dec_float.hpp> #include <complex> using namespace boost::multiprecision; std::complex<cpp_dec_float_50>(1.0, 2.0) / std::complex<cpp_dec_float_50>(1.0, 2.0) in Visual Studio 2012 with an error C2440 because the implementation of complex tries to cast to double in internal functions like _Isinf or _Isnan. Is this an error on my part

问题 so, I'm trying to build a simple big integer class, I've read some pages on the internet and all that, but I'm stuck. I know the theory and I know that I need a carry but all examples I've seen, they focuded more in chars and in base 10 and well, I'm using a different approach to make it a bit more faster. I would appreciate some help with the plus assignment operator, the rest of it I'll try to figure it out by myself. #include <iostream> #include <string> #include <vector> using std::cout;