integer-arithmetic Questions
3
Solved
I am writing a cycle method for a list that moves an index either forwards or backwards. The following code is used to cycle backwards:
(i-1)%list_length
In this case, i is of the type usize, me...
Saintsimonianism asked 23/12, 2016 at 12:24
15
I have this Bash script and I had a problem in line 16.
How can I take the previous result of line 15 and add
it to the variable in line 16?
#!/bin/bash
num=0
metab=0
for ((i=1; i<=2; i++)); ...
Trimetallic asked 14/6, 2011 at 19:25
2
Is there an easy, efficient and correct (i.e. not involving conversions to/from double) way to do floored integer division (like e.g. Python offers) in C#.
In other words, an efficient version of ...
Marleah asked 21/1, 2015 at 4:31
4
Solved
I have an int x. For simplicity, say ints occupy the range -2^31 to 2^31-1. I want to compute 2*x-1. I allow x to be any value 0 <= x <= 2^30. If I compute 2*(2^30), I get 2^31, which is an i...
Ryals asked 17/10, 2022 at 20:5
1
Solved
I was wondering whether x**2 or x*x is faster
def sqr(x):
for i in range (20):
x = x**2
return x
def sqr_(x):
for i in range (20):
x = x*x
return x
When I time it, this is what I get:
The ti...
Centrum asked 7/5, 2022 at 12:57
5
Can anyone provide some code examples that act differently when compiled with -fwrapv vs without?
The gcc documentation says that -fwrapv instructs the compiler to assume that signed arithmetic ove...
Rosenthal asked 11/11, 2017 at 0:5
5
Solved
Are there any branch-less or similar hacks for clamping an integer to the interval of 0 to 255, or a double to the interval of 0.0 to 1.0? (Both ranges are meant to be closed, i.e. endpoints are in...
Grecism asked 25/7, 2015 at 21:17
6
Solved
I have come across code from someone who appears to believe there is a problem subtracting an unsigned integer from another integer of the same type when the result would be negative. So that code ...
Sycee asked 28/8, 2011 at 13:59
2
Solved
Assume we have 3 bits to play with. I am going to represent plus and minus 3 in 2's complement:
+3 = 0b011
-3 = 0b101
When doing addition you always have a dangling bit when an overflow happens li...
Vashtivashtia asked 29/7, 2021 at 21:9
4
Solved
I'm trying to implement a fast primality test for Rust's u32 and u64 datatypes. As part of it, I need to compute (n*n)%d where n and d are u32 (or u64, respectively).
While the result can easily f...
Grand asked 28/8, 2017 at 11:39
9
Solved
Is there any predefined function in c++ to check whether the number is square of any number and same for the cube..
Jemmy asked 11/10, 2009 at 5:35
1
Solved
There is a relatively well-known trick for unsetting a single right-most bit:
y = x & (x - 1) // 0b001011100 & 0b001011011 = 0b001011000 :)
I'm finding myself with a tight loop to clear n ...
Bassorilievo asked 20/1, 2021 at 20:50
4
Solved
Assuming that uint is the largest integral type on my fixed-point platform, I have:
uint func(uint a, uint b, uint c);
Which needs to return a good approximation of a * b / c.
The value of c is gr...
Danelle asked 28/10, 2020 at 7:51
1
My problem is limited to unsigned integers of 256 bits.
I have a value x, and I need to descale it by the ratio n / d, where n < d.
The simple solution is of course x * n / d, but the problem is...
Homoeo asked 25/7, 2020 at 18:17
17
Solved
How can I subtract two integers in C without the - operator?
Demmy asked 31/3, 2009 at 7:30
1
Solved
Does anyone know how to do arithmetic assignment for integer variables in set_fact module? Currently, I managed to do it by using String variable using Jinja2 template like this:
- set_fact:
fla...
Canso asked 16/4, 2020 at 8:20
1
Solved
EDIT2: As @ShadowRanger pointed out, this is a Numpy phenomenon, not Python. But when doing the calculations in Python with list comprehensions (so x+y becomes [a+b for a,b in zip(x,y)]) then all a...
Brok asked 2/8, 2019 at 11:15
2
Solved
Why is it that Rust's u64 primitive expects a u32 exponent?
error[E0308]: mismatched types
--> src/protagonists.rs:13:25
|
13 | return root.pow(self.secret) % prime;
| ^^^^^^^^^^^ expected u...
Cumae asked 19/7, 2019 at 21:2
8
I have to store an integer value that is larger than the maximum value for the long datatype. How would I store and manipulate this value in memory?
Please illustrate it through an example, if pos...
Caitiff asked 12/2, 2010 at 15:35
2
Solved
Many lossless algorithms in signal processing require an evaluation of the expression of the form ⌊ a / 2b ⌋, where a, b are signed (a possibly negative, b non-negative) integer...
Gill asked 12/12, 2018 at 15:20
4
Solved
The following Python 3.x integer multiplication takes on average between 1.66s and 1.77s:
import time
start_time = time.time()
num = 0
for x in range(0, 10000000):
# num += 2 * (x * x)
num += 2 ...
Wasserman asked 1/12, 2018 at 12:40
1
Solved
Consider this code:
val x1: Byte = 0x00
val x2: Byte = 0x01
val x3: Byte = x1 + x2;
This gives a compile error, because the result of adding 2 Bytes is an Int.
To work around this, I need to m...
Sankey asked 17/10, 2018 at 8:42
5
Solved
I know such topic was asked several times, but my question is about overflow on full 32 bits of int. For example:
11111111111111111111111111111111 +
00000000000000000000000000000001 =
00000000...
Jahn asked 20/1, 2014 at 12:2
10
Solved
From the comments on my answer here, the question was asked (paraphrase):
Write a Python program to find a 4 digit whole number, that when multiplied to itself, you get an 8 digit whole numbe...
Buckjump asked 5/4, 2018 at 12:59
3
Solved
int plus unsigned int returns an unsigned int. Should it be so?
Consider this code:
#include <boost/static_assert.hpp>
#include <boost/typeof/typeof.hpp>
#include <boost/type_trait...
Carburize asked 6/4, 2012 at 18:28
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