Questions tagged [numbers]

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29
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5answers
5k views

What is the most efficient way to store a numeric range?

This question is about how many bits are required to store a range. Or put another way, for a given number of bits, what is the maximum range that can be stored and how? Imagine we want to store a ...
-3
votes
5answers
128 views

Number system conversion

Why can't we directly convert octal number to base 8 to hexadecimal base 16 directly ? We can convert to octal by first converting it into binary equivalent, or by converting it to decimal equivalent ....
2
votes
1answer
88 views

If you can store BigInts in a more optimal way than an array

This suggests just storing BigInts as an array: // n = -123 var n = { sign: -1, digits: [3, 2, 1] }; However, if you have "big ints", that array will get large: var n = { sign: -1, ...
2
votes
3answers
268 views

Are all pseudo randomly generated numbers within a given period unique?

This will of course depend on the algorithm generating the pseudo random numbers, but what I'm wondering is whether practical, usable pseudo-random number generating algorithms exist that never repeat ...
1
vote
1answer
188 views

How does this function for calculating modular exponentiation work ?

I know that the rule in maths for modulus is this: ab mod n =(a mod n ) (b mod n) mod n I have found the following code for computing the modular exponentiation: pow(base,exponent,modulus){ if (...
5
votes
1answer
401 views

how to stop denormals from messing up a real-time process (like an audio app or plug)

So there is an Intel page about what to do about denorms. (BTW, I know exactly what denormals are and am quite familiar with IEEE-754 floating point standard.) I have two questions: What are the ...
12
votes
9answers
4k views

Why are unsigned numbers implemented?

I can't figure out why microprocessor systems implement unsigned numbers. I guess the cost is just double the number of conditional branches, since greater than, less than, .etc, need a different ...
18
votes
7answers
1k views

Why does Java have primitives for different size numbers?

In Java there are primitive types for byte, short, int and long and the same thing for float and double. Why is it necessary to have a person set how many bytes should be used for a primitive value? ...
0
votes
1answer
113 views

Encoding a signed number using a custom alphabet

When encoding a sequence of bits into a string (using an alphabet that is not yet known at compile time and with the goal that the resulting string is as short as possible and that this whole process ...
2
votes
1answer
602 views

BigDecimal for Calculation with and Display of Stock Shares and Prices?

I'm receiving flat files with the stock price and number of held shares for an account. One file contains the price and shares to 6 decimal places. The other file contains the price and shares to 12 ...
-2
votes
1answer
992 views

What is 16 bit word's equivalent in decimal?

Question: For a 16 bit word with 6 bits for an opcode How many different instructions could I fit into the instruction set? What is the largest number that I could use as data? Answer:...
0
votes
1answer
431 views

Combine sequences of numbers with “variable bitlengths” into short unique strings

It is not unlikely that what I want to do is not possible, but it doesn't hurt to ask. Imagine a set of lists, each containing positive integers (in my case, a list always consists of four integers, ...
84
votes
6answers
17k views

Why are floats still part of the Java language when doubles are mostly recommended instead?

In every place I've looked, it says that double is superior to float in almost every way. float has been made obsolete by double in Java, so why is it still used? I program a lot with Libgdx, and ...
2
votes
2answers
285 views

Should arbitrary numbers be stored as strings in a database?

I'm using Google as a login system for my latest project. So, my users table has a column named googleid, which stores Google's unique user id, which is a number, with a few dozen digits. For example, ...
6
votes
1answer
707 views

Exclusive upper bound in random number range

Why do languages' random number generators tend to return a value exclusive of the upper bound of the range? For example, an implicit range - JavaScript's random() method "Return a random number ...
-1
votes
1answer
693 views

Find missing number in sequence in string [closed]

I have a string that contains numbers in sequence. There are no delimiters between numbers. I have to find missing number in that sequence. For example: 176517661768 is missing the number: 1767 ...
2
votes
3answers
1k views

Is there any programming language(s) which has mathematical number types? [closed]

I may not have worded the title correctly. Is there any programming language(s) which deals with natural mathematical number types rather than the typical data types we see like Int32, Int64, Float, ...
3
votes
2answers
721 views

How widespread is the use of arabic numerals in Japanese and Chinese?

I'm localising a times-table app aimed at children. I understand that the Japanese and Chinese languages have a variety of ways to represent numbers. I also have read that, particularly with Japanese, ...
0
votes
2answers
410 views

What is the best type to represent a number in java and why? [closed]

I am developing a dynamically typed, interpreted programming language, which is interpreted by a runtime written in Java. As Java is statically typed, I need to define how the numbers used in the ...
1
vote
2answers
135 views

How to implement rounding in an all-purpose stack language using different types?

Disclaimer: If you are not terribly interested in numerics and mathematical processes, this is most likely nothing for you. I am currently a bit stuck in a development process of a private project I ...
0
votes
5answers
817 views

Is String processing more complex than number processing in programming languages?

I feel that string processing is always more complex than Numbers or mathematical processing. Are our programming languages are designed this way that mathematical operations are pretty much straight ...
1
vote
3answers
186 views

Generate random numbers with certain spikes? [duplicate]

I am trying to generate random numbers to simulate steering wheel angles and velocities of a car. So for steering wheels the random numbers could go like 1,2,4,6,4,3,40,0. I can generate random ...
1
vote
4answers
2k views

Generate unique integer from two integers with algorithm

I am currently trying to come up with an algoritm which would take at least two numbers (say user IDs) and then come up with an unique number which is generated based on these two numbers. Each ...
-5
votes
1answer
63 views

Distributivity and Associativity for 32/64bit signed integers [closed]

I'm looking into 32/64bit signed integers and their algebraic properties. I am quite sure that the the three operators +, - and * fulfill the distributive and associative property (integer division ...
44
votes
2answers
6k views

Why do some languages round to the nearest EVEN integer?

Programming languages like Scheme (R5RS) and Python (see this Question) round towards the nearest even integer when value is exactly between the surrounding integers. What is the reasoning behind ...
0
votes
3answers
1k views

What is more efficient, a single square root or multiple divisions?

Say I make a program that calculates all possible (integral) factors of a certain number that has been input. Is it theoretically more efficient to check with all integers up to the square root of ...
0
votes
1answer
399 views

Representing the hierarchy of groups of numbers using type inheritance

I've run into an interesting conundrum while coding my own implementations for the basic sets of mathematical numbers (Natural, Integer, Rational, Irrational, Real, Complex). I'm doing this mostly for ...
4
votes
3answers
3k views

When is a number a magic number?

Over the last couple of months I have been diving into coding standard IfSQ. As a part of this IfSQ standard, a rule is to not use Magic Numbers. While I don't have a problem with building this rule ...
1
vote
1answer
323 views

Why are floats called “real numbers” in some languages?

Some programing languages, notably Pascal, have a type of numbers called "real". However, mathematically speaking, these types aren't real. For them to be "real", these types have to be able to ...
4
votes
2answers
335 views

Trivially Sortable Encoding for Arbitrary-Precision Decimals

I'm looking for a reasonably(*) space-efficient way to encode arbitrary-precision decimals (e.g. BigDecimal), such that when sorting the bit-pattern of the encodings lexicographically, the numbers ...
0
votes
4answers
493 views

Why is it an issue that it takes 2 digits to represent the number 10 in decimal? [closed]

So we use hexadecimal which has the advantage of going up to 15 in single digits A-F, but why is it an issue that it takes 2 digits to represent the number 10 in decimal? I was reading up about ...
42
votes
3answers
6k views

Are there numbers that are not representable in base 10 but can be represented in base 2?

C# has the decimal type which is used for numbers that needs exact representation in base 10. For instance, 0.1 cannot be represented in base 2 (e.g. float and double) and will always be an ...
0
votes
1answer
2k views

Algorithm for base-conversion in C?

I put in this code which does what it's supposed to do, but perhaps there is a better or more general approach? I'm converting a 4-digit base 10 number e.g. "11" to base 16 e.g. "17" (which gets ...
15
votes
4answers
2k views

How to identify unstable floating point computations?

In numerics, it is very important to be able to identify unstable schemes and to improve their stability. How to identify unstable floating point computations? I am working on a very complex ...
0
votes
1answer
625 views

How many ALU additions are needed to add three numbers?

Please give reasons for your answer. As I found, two additions are needed. This is because every number to be add needs to changed to binary. Then addition is done between two binary numbers where ...
36
votes
1answer
2k views

Where does paypal's 92233720368547800 number come from? [closed]

There has been a story in the news about a man whose Paypal account was accidentally credited with $92,233,720,368,547,800. Where does this number come from? What sort of programming bug is likely to ...
1
vote
1answer
1k views

Sum of divisors of numbers of the range ~ 10^6

I was trying to find the sum of divisors of numbers upto 106. The test cases are like of the order of 105. I have done some pre processing like int divisors(int num) { int sum=0; for(int i=1;...
9
votes
7answers
10k views

Why are there so many numeric types (bit, int, float, double, long)?

I've learned PHP, Java, and C. Now I'm curious as to why there are so many types of numerical data types like bit, int, float, double, and long. Why not make only one type for numericals? Is there ...
5
votes
3answers
30k views

What is the time complexity of the algorithm to check if a number is prime?

What is the time complexity of the algorithm to check if a number is prime? This is the algorithm : bool isPrime (int number) { if (number < 2) return false; if (number == 2) return ...
192
votes
7answers
251k views

When do you use float and when do you use double

Frequently in my programming experience I need to make a decision whether I should use float or double for my real numbers. Sometimes I go for float, sometimes I go for double, but really this feels ...
0
votes
2answers
307 views

Algorithm for picking reasonable min/max vals given a single value

I am making a simplistic in-browser IDE for some very domain-specific coding. Because I like Bret Victor's thoughts on Learnable Programming so much I thought I'd throw in some draggable numbers ala ...
10
votes
3answers
460 views

Why is the minimum value of ints, doubles, etc 1 farther from zero than the positive value?

I know it has something to do with 2's complement and adding 1, but I don't really get how you can encode one more number with the same amount of bits when it comes to negative numbers.
9
votes
3answers
39k views

Is there something special about the number 65535?

2¹⁶-1 & 2⁵ = 2⁵ (or? obviously ?) A developer asked me today what is bitwise 65535 & 32 i.e. 2¹⁶-1 & 2⁵ = ? I thought at first spontaneously 32 but it seemed to easy whereupon I thought ...
2
votes
1answer
488 views

Filling array with numbers from given range so that sum of adjacent numbers is square number

Problem: Fill all the cells using distinct numbers from <1,25> set, so that sum of two adjacent cells is a square number. (source: http://grymat.im.pwr.wroc.pl/etap1/zad1etp1213.pdf; numbers 20 ...
2
votes
2answers
288 views

Which numeral systems are useful in computer science?

I am wondering which numeral system different programmers are using, or would use if their language has support for them. As an example, in C++ we can use: Octal by prefixing with 0 (e.g. 0377) ...
24
votes
6answers
13k views

Why don't computers store decimal numbers as a second whole number?

Computers have trouble storing fractional numbers where the denominator is something other than a solution to 2^x. This is because the first digit after the decimal is worth 1/2, the second 1/4 (or 1/...
29
votes
4answers
7k views

Has Little Endian won?

When teaching recently about the Big vs. Little Endian battle, a student asked whether it had been settled, and I realized I didn't know. Looking at the Wikipedia article, it seems that the most ...
2
votes
4answers
6k views

Understanding binary numbers in terms of real world objects [closed]

When I represent a number in the decimal system, I have an intuitive knowledge of what it amounts to. For example take the number '10': I understand that it means 10 apples or 10 people... i.e I can ...
5
votes
2answers
13k views

binary representation in Python and keeping leading zeros

I wanted to use the base64 Python library to encode a sequence of binary digits into base 64. Would it be possible to do it without converting to a string? If not, what is the best way to do it, ...
3
votes
3answers
3k views

In programming light, what is special about the number 1223? [closed]

Just came across this post on reddit, where someone was charged $1,223 for a "FREE STEAK SALAD". I was trying to figure out 'Why 1223?' thinking that this might be a programming error somewhere. But ...