# Tagged Questions

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79 views

### Choosing an epsilon when comparing floating point numbers across different systems

I am transcribing thousands of lines of computational code from MATLAB to C++. I don't fully understand the math myself, but I can run it with MATLAB, assume it's correct, and compare the results to ...
13k 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 ...
152 views

### Floating point accuracy and conversions

I am trying to build a class where user can compute floating operations with a particular accuracy. For example, if the user wants to have up to 4 digit accuracy, everything less than 0.0001 is zero ...
164 views

### Floating point calculation being too exact

In Java, I've run this method: private static void floatAddition() { float a = 0.1F, b = 0.2F, c = a+b; System.out.println(a + " + " + b + " = " + c); } and the result is 0.3 for ...
70 views

### Floating point absorption phenomena and ULP

Numerical analysis text books talks about the absorption phenomena (Introduction to Numerical Analysis and Scientific Computing; Nabil Nassif; Dolly Khoueiri Fayyad; CRC Press; 2014) when adding ...
258 views

### Avoiding Division by Zero Using Float Comparison

Source code analyzers (like SonarQube) complain about float (or double) equality comparisons because equality is a tricky thing with floats; the values compared can be the results of computations ...
50 views

### avoid nan and inf in floating point multiplication and division

I have the following hypothesis: It is better to reorder mult and div operation in such a way that we can do our best effort to avoid nan, inf and operating with subnormals. The reorder should follow ...
169 views

### Should `Vector<float>.Equals` be reflexive or should it follow IEEE 754 semantics?

When comparing floating point values for equality, there are two different approaches: NaN not being equal to itself, which matches the IEEE 754 specification. NaN being equal to itself, which ...
113 views

### How to convert byte-array (4 bytes) back into float? [closed]

A piece of code I'm trying to debug generated a sequence of 4 bytes from a known float number. I'm trying to verify the float number given the four bytes. The (known) float 8.03 generated the bytes ...
99 views

### Rationale of IEEE754 direct rounding behavior near infinity [closed]

A preface: it's well known that IEEE754 defines five rounding modes (in 2008 edition terms, with my abbreviations): rounding to nearest, ties to even (RNE) - the default mode for binary arithmetic; ...
125 views

### Is order of arguments in an arithmetic expression important to achieve as most exact result as possible (speed is not necessary)?

Actually, in this question I do not ask about particular language or architecture, however I understand there might be some differences. In physics / engineering it is usually better to handle ...
2k views

### How to calculate min/max values of floating point numbers?

I'm trying to calculate the min/max, or the lowest to highest value range of a 48 bit floating point type MIL-STD-1750A (PDF) (WIKI). Ex: How a double range is 1.7E +/- 308 I've looked around for ...
901 views

### Why does Python's math.ceil return a float?

While I understand that the difference between integral and long values is blurred in Python, the difference between floats and integral values is not. Therefore, I'm having a difficult time ...
140 views

### floating-point number stored in float variable has other value [duplicate]

I'm reading a book about C programming By "King.K.N" and I'm reading the following statement: If we store 0.1 in a float variable, we may later find that the variable has a value such as 0....
272 views

### How can unums emulate IEEE's negative zero?

I am currently reading "The End of Error - Unum Computing" by John Gustafson (Youtube). What I am still not sure about is how the cases handled in IEEE by negatively signed zero are handled with unums....
196 views

### How can a computer round the last digit in a floating point representation?

I'm confused by how a computer rounds off the last digit in the floating point representation. For example, I'm told that x=1.24327789 is stored in a computer with a 6-digit capacity then it;s ...
85 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 ...
1k views

### Why is negative zero important?

I'm confused about why we care about different representations for positive and negative zero. I vaguely recall reading claims that having a negative zero representation is extremely important in ...
205 views

### Is the behaviour of floating-point arithmetic defined by the c++ standard?

I started writing this as a SO question, but I think it's better suited here. While I'm happy for a simple answer I'm also fond of the "Teach a Man to Fish" philosophy so I'm happy for people to point ...
676 views

### adding the digits of a number

I am trying to write a program that asks the user for a decimal number and then calculates the sum of its digits. for example if the number is 123.25 then the sum will be 1+2+3+2+5=13. I decided to ...
88 views

### Is this statement correct for floating point numbers?

The decimal point can "float" to accommodate larger numbers while staying in 32-bits which is why float is considered "in-accurate" Is this an accurate statement? I want to know if I understand ...
6k views

### Why are floating point numbers used often in Science/Engineering?

While investigating the accuracy of floating point numbers, I've seen in a few places a statement similar to "float and double are (designed for/used often in) engineering and scientific calculation"...
1k views

### How is a floating point number represented in Java?

Which algorithm does java uses to convert floating point number (Ex:0.15625) into binary(0.00101)? Whether java uses normalized form or denormalized format? If I type float ab=0.15625 in Java source ...
261 views

### Implied precision of floating-point functions

While reviewing another programmer's implementation of a function to calculate the normal distribution CDF, I made a suggestion to either replace the entire implementation with Python's built-in ...
163 views

### How are some IEEE 754 floats printed succinctly?

Using this calculator, I can see how the decimal ".8" and the expression ".7 + .1" have different representations: .8 = 1.1001100110011001100110011001100110011001100110011010 *2-1 .7 + .1 = 1....
45 views

### Time passage arithmetic explanation

I ported this from http://www.effectgames.com/effect/article.psp.html/joe/Old_School_Color_Cycling_with_HTML5 some time ago. However i'm now wanting to modify it for the purpose of changing it from ...
5k 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 ...
9k views

### Why is BigDecimal the best data type for currency? [duplicate]

I was reading this question and the accepted answer says that BigDecimal is the best type for representing currency values. I've also seen several other questions support the use of big decimal. Why ...
657 views

### Custom class for monetary amount (money value) instead of BigDecimal

On StackOverflow I found multiple advices to stick with BigDecimal in Java instead of reinventing the wheel. Despite that, I decided to create my custom class, and I would ask if that was a good idea ...
2k views

### When do rounding problems become a real problem? Is the least significant digit being one off really a big deal? [duplicate]

If I do .1 + .1 + .1 in Python, I get 0.30000000000000004. (I am not asking about Python in particular, and do not want Python specific answers.) The only problem I can see with this is 0....
275 views

### Will we go back(?) to fixed-point arithmetic in the near future? [closed]

As far as I recall, this has been the ongoing trend of the past, I'm just a student, so I might be wrong: Long ago: Integer numbers and calculations. Very precise, however cannot present a big range....
5k views

### Why do we still use floats? [duplicate]

I understand why floats served a purpose in the past. And I think I can see why they're useful in some simulation examples today. But I think those example are more exceptional than common. So I ...
352 views

### Why does IEEE 754 Single Float have 8 bits for exponent but only allow 38 base ten Max Value

Why is it that the IEEE 754 standard provide 8 bits for the exponent but puts a range maximum of 38 on the largest acceptable exponent? Seems kind of ridiculous to have the data storage there but not ...
600 views

### Unit (regression) testing scientific algorithms given floating point behavior

I have been working on a project and running into a very difficult problem. The problem can be stated simply as how to unit-test numerical algorithms. However if you just took this simple statement ...
9k views

### Can anyone explain representation of float in memory?

This is not duplicate question as I read the previous question. Can anyone help me in understanding how float values are stored in the memory . My doubt is here float values contain '.' (for example ...
127 views

### How can I handle clock hands using doubles that suffers at most O(log n) corrupt bits at nth frame of display?

I presently have a clock app that calculates from scratch at every iteration. This means O(1) corrupt bits in my doubles and heavy object creation and deletion as well. I am wary of running ...
335 views

### Generic term for “objects” vs “fundamental types”?

What are the exact terms to call data types with a logic structure (like C structures, C++ or Java objects) versus fundamental data types (like numeric types, characters, booleans...) independently of ...
458 views

### Why is float the default in the majority of languages?

In programming languages, for represent numbers you have (mainly) two types: Int(s) and floats. The us of Int is very easy. However floats cause a lot of unexpected surprises: http://anh.cs.luc.edu/...
5k views

### How Lua handles both integer and float numbers?

As far as I remember myself programming I was taught not to compare floating point numbers for equality. Now, while reading Programming in Lua about Lua number type, I found following: The number ...
3k views

### Addition of double's is NOT Equal to Sum of the double as a whole

I am aware of the floating point errors as I had gained some knowledge with my question asked here in SE Floating Point Errors. What I am finding it difficult to understand is, the output of the ...
3k views

### Solutions for floating point rounding errors

In building an application that deals with a lot of mathematical calculations, I have encountered the problem that certain numbers cause rounding errors. While I understand that floating point is not ...
705 views

### Implementing base-10 floating point division

I'm implementing floating-point arithmetic, for a micro-controller which does not support floating point numbers, in either hardware or software. (Software being "written" in a sort of electrical ...
893 views

### Is (1/(1/x)) always a perfect round trip?

Is the following guaranteed to return true for all numerical and non-zero values of x? bool IsRoundTrip(double x) { double y = 1 / (1 / x); return x == y; } What conditions would cause a ...
2k views

### Performance and other issues with using floating point types in C++

Being interested in C++ performance programming there is one aspect I really have no clue about- and that is the implications of using floating point calculations vs doubles vs normal integer ...
163k 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 ...
963 views

### Dummy float values to force floating-point operations

It is common to use idioms such as: x/60.0 to force a floating-point division when x is an integer in languages which do not have distinct operators for integer and decimal division. Is this an ...
3k views

### in Objective-C, value of type double/float can only be NAN, INFINITY, & normal number?

I knew double or float value can be not only normal value(-1.3, 0, 1.0, 2.3) but also NAN and INFINITY in Objective-C. Is there other special values except for NAN and INFINITY for double/float value ...
2k views

### How to remove the boundary effects arising due to zero padding in scipy/numpy fft?

I have made a python code to smoothen a given signal using the Weierstrass transform, which is basically the convolution of a normalised gaussian with a signal. The code is as follows: #Importing ...