How to Accurately Compare Floating-Point Numbers for Equality in Go?

Go Float Comparison: A Comprehensive Approach

Comparing floating-point numbers (floats) for equality in Go requires a nuanced approach due to the inherent limitations and complexities of floating-point arithmetic.

Using Bit Representation: A Limited Solution

The provided code compares floats by examining their binary representations and allowing for a one-bit difference. However, this approach is flawed as it disregards the significance of the bit position in the binary representation. For instance, a difference in the least significant bit for very large floats may be inconsequential, while for very small floats, it could represent a significant deviation.

A More Precise and Generic Approach

A more robust and accurate method involves calculating the difference between the two floats using the math.Abs function. By setting an appropriate threshold, you can determine if the difference is negligible and consider the floats "almost equal."

This approach allows you to:

• Handle both small and large floats effectively
• Eliminate the subjectivity of the one-bit difference heuristic
• Set the equality threshold based on the specific application requirements

Example Implementation

Below is an example implementation:

import (
    "fmt"
    "math"
)

const float64EqualityThreshold = 1e-9

func almostEqual(a, b float64) bool {
    return math.Abs(a - b) <= float64EqualityThreshold
}

func main() {
    a := 0.1
    b := 0.2
    fmt.Println(almostEqual(a + b, 0.3)) // true
}

This solution is more generic and adaptable, allowing you to handle various scenarios and set the equality threshold appropriately for your application.

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