Benchmark: Floats: toFixed vs toPrecision vs Math.round

Script Preparation code:

var someFloat = 0.123456789;

Tests:

parseFloat() + toFixed(4)
parseFloat(someFloat.toFixed(4));
parseFloat() + toPrecision(4)
parseFloat(someFloat.toPrecision(4));
Math.round(*10000)/10000
Math.round(someFloat*10000)/10000;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
parseFloat() + toFixed(4)
parseFloat() + toPrecision(4)
Math.round(*10000)/10000

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0

Browser/OS: Firefox 140 on Linux

View result in a separate tab

Test name	Executions per second
parseFloat() + toFixed(4)	11696507.0 Ops/sec
parseFloat() + toPrecision(4)	9823646.0 Ops/sec
Math.round(*10000)/10000	1504486144.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

The benchmark measures the performance of three different methods for rounding a floating-point number:

1. `toFixed()`
2. `toPrecision()`
3. `Math.round()` with multiplication and division by 10,000 to avoid floating-point precision issues.

**Options Compared:**

* `parseFloat(someFloat.toFixed(4))`: Uses the `toFixed()` method to convert the float to a string with four decimal places, then parses it back to a float using `parseFloat()`.
* `parseFloat(someFloat.toPrecision(4))`: Uses the `toPrecision()` method to convert the float to a string with four decimal places, then parses it back to a float using `parseFloat()`.
* `Math.round(someFloat*10000)/10000`: Multiplies the float by 10,000, rounds it using `Math.round()`, and then divides the result by 10,000.

**Pros and Cons of Each Approach:**

1. **`toFixed()`**: Pros:
	* Simple to implement.
	* Works well for small numbers with a fixed number of decimal places.
Cons:
	* Can lead to loss of precision due to string conversion.
	* May not work correctly for very large or very small numbers.
2. **`toPrecision()`**: Pros:
	* More flexible than `toFixed()`, allowing for arbitrary precision.
Cons:
	* Less intuitive and more complex to use.
	* May be slower due to the extra operation.
3. **`Math.round()` with multiplication and division by 10,000**:
	* Avoids floating-point precision issues.
	* Works well for large numbers.

**Other Considerations:**

* `toFixed()` is often used when working with user input or data that needs to be presented in a fixed format. However, it can lead to loss of precision if the original value has more decimal places than specified.
* `toPrecision()` is useful when working with very large or very small numbers where precision is critical. However, it may be slower due to the extra operation.

**Library:**

There are no external libraries used in this benchmark definition.

**Special JS Features/Syntax:**

None mentioned explicitly. The benchmark only uses standard JavaScript features and syntax.

Now, let's look at the test cases:

The three test cases measure the performance of the three different rounding methods on a single float value `someFloat` with four decimal places. The test cases are designed to exercise each method individually, without considering interactions or combinations between them.

If you're interested in exploring alternative approaches or optimizing these tests, some potential directions include:

* Using native WebAssembly or AssemblyScript for performance-critical code.
* Investigating the use of SIMD (Single Instruction, Multiple Data) instructions for floating-point operations.
* Optimizing the `Math.round()` multiplication and division by 10,000 to reduce precision issues.
* Implementing a custom rounding algorithm with fine-grained control over precision and performance.

Related benchmarks:

Floats: toFixed vs toPrecision vs Math.round (version: 0)

Comparing performance of: parseFloat() + toFixed(4) vs parseFloat() + toPrecision(4) vs Math.round(*10000)/10000

Created: 5 years ago by: Guest

Jump to the latest result

parseFloat() + toFixed(4)

parseFloat() + toPrecision(4)

Math.round(*10000)/10000

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):