bitarray

问题 I use the library bitarray to manage my bits conversion and to write a binary file in Python. The bitarray.to01() before writing to file is of length 4807100171 . For some reason I can't make sense of, after getting the bits fromfile ( b.fromfile(file) ) and then converted to a string of 0s and 1s with to01() , there is not only 0s and 1s in my string ( \x00 ) and then, when I work with it, I get this error: ValueError: invalid literal for int() with base 2: '0000000000000000\x00\x00\x00\x00

问题 I'm writing a large bitarray to a file using this code: import bitarray bits = bitarray.bitarray(bin='0000011111') #just an example with open('somefile.bin', 'wb') as fh: bits.tofile(fh) However, when i attempt to read this data back using: import bitarray a = bitarray.bitarray() with open('somefile.bin', 'rb') as fh: bits = a.fromfile(fh) print bits it fails with 'bits' being a NoneType. What am i doing wrong? 回答1: I think "a" is what you want. a.fromfile(fh) is a method which fills a with

问题 I have a long sequence of bits stored in an array of unsigned long integers, like this struct bit_array { int size; /* nr of bits */ unsigned long *array; /* the container that stores bits */ } I am trying to design an algorithm to reverse the order of bits in *array. Problems: size can be anything, i.e. not necessarily a multiple of 8 or 32 etc, so the first bit in the input array can end up at any position within the unsigned long in the output array; the algorithm should be platform

问题 I was writing a function for boolean 2d arrays: function foo(A::Array{Bool,2}) ... end Evaluating and testing it with A = randbool(3,3) foo(A) returns ERROR: 'foo' has no method matching foo(::BitArray{2}) Obviously, randbool() generates a BitArray , whereas I assumed randbool() would yield an Array{Bool} . How are Array{Bool} and BitArray related? Why do they both exist? Can I write foo() in such a way that it accept both input types using a single method (since I can't see a difference)?

问题 I was writing a function for boolean 2d arrays: function foo(A::Array{Bool,2}) ... end Evaluating and testing it with A = randbool(3,3) foo(A) returns ERROR: 'foo' has no method matching foo(::BitArray{2}) Obviously, randbool() generates a BitArray , whereas I assumed randbool() would yield an Array{Bool} . How are Array{Bool} and BitArray related? Why do they both exist? Can I write foo() in such a way that it accept both input types using a single method (since I can't see a difference)?

问题 What is the best way of implementing a bit array in JavaScript? 回答1: Here's one I whipped up: UPDATE - something about this class had been bothering me all day - it wasn't size based - creating a BitArray with N slots/bits was a two step operation - instantiate, resize. Updated the class to be size based with an optional second paramter for populating the size based instance with either array values or a base 10 numeric value. (Fiddle with it here) /* BitArray DataType */ // Constructor

问题 I'm writing a time-critical piece of code in C# that requires me to convert two unsigned integers that define an inclusive range into a bit field. Ex: uint x1 = 3; uint x2 = 9; //defines the range [3-9] // 98 7654 3 //must be converted to: 0000 0011 1111 1000 It may help to visualize the bits in reverse order The maximum value for this range is a parameter given at run-time which we'll call max_val . Therefore, the bit field variable ought to be defined as a UInt32 array with size equal to

问题 I'm writing a time-critical piece of code in C# that requires me to convert two unsigned integers that define an inclusive range into a bit field. Ex: uint x1 = 3; uint x2 = 9; //defines the range [3-9] // 98 7654 3 //must be converted to: 0000 0011 1111 1000 It may help to visualize the bits in reverse order The maximum value for this range is a parameter given at run-time which we'll call max_val . Therefore, the bit field variable ought to be defined as a UInt32 array with size equal to

问题 I have already wrote a program to this , bits working only if bit array length is multiples of 8 . Can some one help me to get bit array of 5 bits converted into byte both functions work only when it have bit array in multiple of 8 . public static byte[] BitArrayToByteArray(BitArray bits) { byte[] ret = new byte[bits.Length / 8]; bits.CopyTo(ret, 0); return ret; } public static byte[] ToByteArray(this BitArray bits) { int numBytes = bits.Count / 8; if (bits.Count % 8 != 0) numBytes++; byte[]

问题 I need to keep track of around 10000 elements of an array in my algorithm .So for this I need boolean for each record.If I used char array to keep track of 10000 arrays (as 0/1),it would take up lot of memory. So Can I create an bit array of 10000 bits in Cuda where each bit represents corresponding array record? 回答1: As Roger said, the answer is yes, CUDA provides the same bitwise operations (i.e. >> , << and & ) as normal C so you can implement your bit array essentially normally (almost,