Benchmark: power of two vs shift left then unsigned shift right vs constant

Tests:

power of two
return 2**31;
shift left then unsigned shift right
return 2<<31>>>0;
constant
return 2147483648;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
power of two
shift left then unsigned shift right
constant

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) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser/OS: Chrome 138 on Linux

View result in a separate tab

Test name	Executions per second
power of two	117927472.0 Ops/sec
shift left then unsigned shift right	106689072.0 Ops/sec
constant	118649832.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 9 months ago):

LLMs can make mistakes. Check important info.

The benchmark tests performance related to three different ways of calculating the value of \(2^{31}\), which is \(2147483648\). The three methods being compared are:

1. **Power of Two (`2**31`)**
   - This is the exponentiation operator in JavaScript that computes \(2^{31}\).
   - Pros: Readable and straightforward, properly denoting the mathematical operation.
   - Cons: Depending on the JavaScript engine's optimization, this method may have different performance characteristics compared to bitwise operations.

2. **Shift Left Then Unsigned Shift Right (`2<<31>>>0`)**
   - This approach uses the bitwise left shift operator followed by an unsigned right shift. It effectively moves the binary representation of the number two to the left by 31 positions and then shifts it back to an unsigned value.
   - Pros: Bitwise operations are often very fast due to lower-level processing, making this method potentially more efficient in performance terms.
   - Cons: This representation may be less readable and can be confusing to those not familiar with bit manipulation.

3. **Constant (`2147483648`)**
   - This method returns a constant value directly.
   - Pros: The fastest option in terms of execution because it does not perform any computation—it simply returns a predefined value.
   - Cons: Limited flexibility since it doesn't demonstrate how to compute the power of two dynamically.

### Benchmark Results Analysis
The benchmark results show the `ExecutionsPerSecond` for each method. Here are the key findings:

- **Constant (`2147483648`)** has the highest execution speed at **118,649,832** executions per second.
- **Power of Two (`2**31`)** is very close in performance with **117,927,472** executions per second.
- **Shift Left Then Unsigned Shift Right (`2<<31>>>0`)** is the slowest among the three, at **106,689,072** executions per second.

### Considerations and Alternatives
- The choice between these methods largely depends on the context of use. If readability and maintainability are critical, the power of two may be preferred. 
- For raw performance in situations where the constant value is known ahead of time, directly using the constant is the optimal approach.
- The bitwise method may be beneficial in performance-critical sections of code but may sacrifice clarity.

### Other Alternatives
Apart from the methods tested, other alternatives for calculating or representing powers of two in JavaScript could include:

- **Using `Math.pow(2, 31)`**: This would provide a clear intent for calculating powers but may not be as fast as direct computations or bitwise operations due to function overhead.
- **Using modern JavaScript syntax (`Math.pow` or even `**`)**: In ES6 and beyond, going with clearer, more maintainable code is often favored, though performance trade-offs should be considered depending on the application context.

In summary, this benchmark provides insights into how different computational methodologies perform in JavaScript while highlighting significant trade-offs among readability, maintainability, and execution speed.

Related benchmarks:

power of two vs shift left then unsigned shift right vs constant (version: 1)

Comparing performance of: power of two vs shift left then unsigned shift right vs constant

Created: 9 months ago by: Guest

Jump to the latest result

power of two

shift left then unsigned shift right

constant

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 9 months ago):