diff --git a/main.go b/main.go index 34d31da..a841d2d 100644 --- a/main.go +++ b/main.go @@ -3,22 +3,49 @@ package main import ( "bufio" "fmt" + "math" "os" "strconv" "strings" ) -// combineFloats takes previous stored floats and new floats, applies an operation, and returns the combined results. -func combineFloats(stored1, stored2, new1, new2 float64) (float64, float64) { - // Example operation: simply adding the new floats to the stored ones. - return stored1 + new1, stored2 + new2 +const NORMAL90CONFIDENCE = 1.6448536269514727 + +func boundsToLogParams(low float64, high float64) (float64, float64) { + + loglow := math.Log(low) + loghigh := math.Log(high) + logmean := (loghigh + loglow) / 2.0 + logstd := (loghigh - loglow) / (2.0 * NORMAL90CONFIDENCE) + return logmean, logstd + +} + +func multiplyLognormals(logmean1 float64, logstd1 float64, logmean2 float64, logstd2 float64) (float64, float64) { + return logmean1 + logmean2, math.Sqrt(logstd1*logstd1 + logstd2*logstd2) +} + +func logParamsToBounds(logmean float64, logstd float64) (float64, float64) { + h := logstd * NORMAL90CONFIDENCE + loglow := logmean - h + loghigh := logmean + h + return math.Exp(loglow), math.Exp(loghigh) +} + +func combineBounds(old_low, old_high, new_low, new_high float64) (float64, float64) { + logmean_old, logstd_old := boundsToLogParams(old_low, old_high) + logmean_new, logstd_new := boundsToLogParams(new_low, new_high) + + logmean_product, logstd_product := multiplyLognormals(logmean_old, logstd_old, logmean_new, logstd_new) + + return logParamsToBounds(logmean_product, logstd_product) } func main() { reader := bufio.NewReader(os.Stdin) - var stored1, stored2 float64 // Variables to store the intermediate results + var old_low, old_high float64 // Variables to store the intermediate results - fmt.Println("Enter two floats separated by a space:") + // fmt.Println("Enter two floats separated by a space:") input, _ := reader.ReadString('\n') input = strings.TrimSpace(input) @@ -27,17 +54,17 @@ func main() { fmt.Println("Please enter exactly two floats.") return } - stored1, err1 := strconv.ParseFloat(tokens[0], 64) - stored2, err2 := strconv.ParseFloat(tokens[1], 64) + old_low, err1 := strconv.ParseFloat(tokens[0], 64) + old_high, err2 := strconv.ParseFloat(tokens[1], 64) if err1 != nil || err2 != nil { fmt.Println("Invalid input. Please ensure you enter two floats.") return } - fmt.Printf("=> %.1f %.1f\n", stored1, stored2) + fmt.Printf("=> %.1f %.1f\n", old_low, old_high) for { - fmt.Println("Enter another two floats separated by a space:") + // fmt.Println("Enter another two floats separated by a space:") input, _ = reader.ReadString('\n') if strings.TrimSpace(input) == "" { break // Exit if no input is given @@ -49,16 +76,15 @@ func main() { continue } - new1, err1 := strconv.ParseFloat(tokens[0], 64) - new2, err2 := strconv.ParseFloat(tokens[1], 64) + new_low, err1 := strconv.ParseFloat(tokens[0], 64) + new_high, err2 := strconv.ParseFloat(tokens[1], 64) if err1 != nil || err2 != nil { fmt.Println("Invalid input. Please ensure you enter two floats.") continue } // Use the abstracted function for combining floats - stored1, stored2 = combineFloats(stored1, stored2, new1, new2) - - fmt.Printf("=> %.1f %.1f\n", stored1, stored2) + old_low, old_high = combineBounds(old_low, old_high, new_low, new_high) + fmt.Printf("=> %.1f %.1f\n", old_low, old_high) } }