Stack Overflow
Stack Overflow

Questions tagged [parity]

A parity bit, or check bit, is a bit that is added to ensure that the number of bits with the value one in a set of bits is even or odd. Parity bits are used as the simplest form of error detecting code.

A parity bit, or check bit, is a bit that is added to ensure that the number of bits with the value one in a set of bits is even or odd. Parity bits are used as the simplest form of error detecting code.

There are two variants of parity bits: even parity bit and odd parity bit. In case of even parity, the parity bit is set to 1, if the number of ones in a given set of bits (not including the parity bit) is odd, making the number of ones in the entire set of bits (including the parity bit) even. If the number of ones in a given set of bits is already even, it is set to a 0. When using odd parity, the parity bit is set to 1 if the number of ones in a given set of bits (not including the parity bit) is even, keeping the number of ones in the entire set of bits (including the parity bit) odd. when the number of set bits is odd, then the odd parity bit is set to 0.[1]

236 questions
73
votes
5 answers

How to know if a number is odd or even in Swift?

I have an array of numbers typed Int. I want to loop through this array and determine if each number is odd or even. How can I determine if a number is odd or even in Swift?
Asif Bilal
  • 4,309
  • 3
  • 17
  • 27
29
votes
6 answers

What is the purpose of the Parity Flag on a CPU?

Some CPUs (notably x86 CPUs) feature a parity flag on their status register. This flag indicates whether the number of bits of the result of an operation is odd or even. What actual practical purpose does the parity flag serve in a programming…
Pharap
  • 3,826
  • 5
  • 37
  • 51
11
votes
2 answers

Computing the Parity

I don't fully understand this algorithm of calculating the parity bit. Can someone please explain in detail? The following code is taken from the 'Hacker's Delight' book: int parity(unsigned x) { unsigned y; y = x ^ (x >> 1); y = y ^ (y >>…
Andrey
  • 111
  • 1
  • 1
  • 3
10
votes
8 answers

How to check if permutations have equal parity?

I am looking for a way to check if 2 permutations (represented by lists) are of the same parity. Note that I am not interested if they are even or odd parity, just the equality. I am new to Python and my naive solution is given below as a reply. I…
Ashwin Nanjappa
  • 76,204
  • 83
  • 211
  • 292
9
votes
5 answers

What is the difference between using mark/space parity and parity none?

What is the purpose having created three type of parity bits that all define a state where the parity bit is precisely not used ? "If the parity bit is present but not used, it may be referred to as mark parity (when the parity bit is always 1) or…
n0n0bstan
  • 1,790
  • 4
  • 15
  • 26
8
votes
1 answer

setting parity with controlTransfer method

Anybody knows how to set the parity with the controlTransfer in Android? I can't find the explanation of this method's parameters anywhere - just some generic info in the ref. One example I found says: conn.controlTransfer(0x40, 0x04, 0x0008, 0,…
user387184
  • 10,953
  • 12
  • 77
  • 147
7
votes
3 answers

Bit parity code for odd number of bits

I am trying to find the parity of a bitstring so that it returns 1 if x has an odd # of 0's. I can only use basic bitwise operations and what I have so far passes most of the tests, but I'm wondering 2 things: Why does x ^ (x + ~1) work? I…
tippenein
  • 189
  • 1
  • 4
  • 11
7
votes
2 answers

How to re-use a Substrate pallet multiple times within the same runtime?

I want to have multiple currencies within the same runtime. There is Balances pallet plugged into the default node template, but if I've got it right it can handle only one currency. How can I re-use the pallet multiple times?
Nikita Chebykin
  • 178
  • 7
6
votes
1 answer

Parity GUI error (getTransactions TypeError: Failed to fetch)

I'm running a parity peer connected to a custom blockchain (PoA), but I can't send a transaction, nor see the list of transactions of my account. I get the following errors (see error screenshot): No 'Access-Control-Allow-Origin' header is present…
Mike
  • 393
  • 1
  • 3
  • 11
6
votes
1 answer

How to make sure transactions take 0 fee in a private Ethereum blockchain?

I have a private parity node setup on my laptop. How can I make sure that there is 0 transaction fee whenever a transaction is posted in this private ethereum blockchain, meaning that I can post a transaction giving "gas: 0"? Example: Account A has…
Suraj Kohli
  • 547
  • 2
  • 5
  • 11
6
votes
1 answer

The probability of selected EFLAGS bits

We all know that when looking at source code it's a safe assumption that the direction flag will be clear. The probability of the direction flag is very low. I wanted to find out about the probabilities of the other flags. That's why I wrote a…
Sep Roland
  • 33,889
  • 7
  • 43
  • 76
6
votes
1 answer

Which is the correct way to determine if two numbers have the same parity?

I found two solutions to find out if two numbers have the same parity (both are odd numbers or both are even). In C++, they look like this: if ((a+b)%2 == 0) and if (a%2 == b%2) The problem is that the first one works on 100% of cases and the…
Tudor Gălățan
  • 121
  • 1
  • 9
6
votes
6 answers

Calculate the parity of a byte in Ruby

What's the best way to calculate if a byte has odd or even parity in Ruby? I've got a version working: result = "AB".to_i(16).to_s(2).count('1').odd? => true Converting a number to a string and counting the "1"s seems a poor way of calculating…
dkam
  • 3,876
  • 2
  • 32
  • 24
6
votes
1 answer

Is there any reason to use (nr & 1 == 0) over (nr % 2 == 0) to check for parity?

Is there any actual difference in performance? Is it faster? (lets say I use it in at least 100 cases in the same program, would it improve my program in terms of speed?)
Stephan
  • 69
  • 6
6
votes
5 answers

How to calculate the parity bit of the following bit sequence?

The sequence is: 00111011 How do i calculate the parity bit for the above sequence? This question is from Databases- The complete book by jeffery ullman (Exercise 13.4.1 a) I am not sure what the answer to this question should be. Is it as simple as…
Nikhil
  • 1,279
  • 2
  • 23
  • 43
1
2 3
…
15 16