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floor vs trunc vs bit shift
(version: 0)
the fastest way to get an integer from a float
Comparing performance of:
floor vs trunc vs bitshift
Created:
3 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var x = 23.45
Tests:
floor
var r = Math.floor(x)
trunc
var r = Math.trunc(x)
bitshift
var r = x >> 0
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
Fork
Test case name
Result
floor
trunc
bitshift
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0
Browser/OS:
Firefox 135 on Ubuntu
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=588042" width="100%" height="500px"></iframe>
trunc
1030.7M/s
bitshift
1023.3M/s
floor
1017.5M/s
View exact numbers
Test name
Executions per second
✓
trunc
1,030,661,632 Ops/sec
bitshift
1,023,328,960 Ops/sec
floor
1,017,464,256 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net. **Benchmark Definition** The benchmark is designed to measure the fastest way to get an integer from a float. The script preparation code sets `x` to a floating-point value (23.45). The benchmark definition specifies three different approaches: 1. **Floor**: Using `Math.floor(x)` to round down to the nearest integer. 2. **Trunc**: Using `Math.trunc(x)` to truncate the decimal part and return an integer. 3. **Bit shift**: Using the bitwise right shift operator (`>>`) to shift the bits of `x` to the right, effectively rounding down to the nearest integer. **Options Comparison** Let's examine each approach: * **Floor (Math.floor)**: This method is straightforward but may introduce precision issues due to floating-point arithmetic limitations. Modern JavaScript engines often use a variant called "round-to-even" for `Math.floor`, which can lead to different results depending on the input value. * **Trunc (Math.trunc)**: This method provides a more accurate result than `floor` because it uses a simpler rounding algorithm that doesn't introduce precision issues. However, its performance may vary depending on the browser and platform. * **Bit shift**: The bitwise right shift operator is generally the fastest way to perform this operation, especially for larger integers. However, its usage can make the code harder to read and understand. **Pros and Cons** Here's a summary of each approach: * **Floor (Math.floor)**: * Pros: Simple to implement. * Cons: May introduce precision issues due to floating-point arithmetic limitations. * **Trunc (Math.trunc)**: * Pros: Provides accurate results with less precision issues than `floor`. * Cons: Performance may vary depending on the browser and platform. * **Bit shift**: * Pros: Generally fastest performance for integer operations. * Cons: Code readability and maintainability may suffer due to its unconventional usage. **Library Usage** The benchmark definition doesn't explicitly mention any libraries. However, `Math` is a built-in JavaScript library that provides mathematical functions like `floor`, `trunc`, and bitwise operators. **Special JS Features or Syntax** None of the approaches in this benchmark require special JavaScript features or syntax beyond basic arithmetic operations. The use of `>>` for bit shifting does introduce some unusual behavior, but it's a widely supported feature in most browsers. **Other Alternatives** Some alternative methods to achieve integer rounding from floating-point numbers include: * Using `Math.round(x)` (which rounds to the nearest even integer) * Implementing your own custom rounding algorithm * Using libraries like Decimal.js or High precision arithmetic Please note that each of these alternatives may have trade-offs in terms of performance, readability, and compatibility with different browsers and platforms.
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