From 9b49d8c41882792cb97d6faba646e89eff0d7549 Mon Sep 17 00:00:00 2001
From: Kasper <kasperkh.kh@gmail.com>
Date: Tue, 3 Jun 2025 01:29:22 +0200
Subject: [PATCH] Remove pow accuracy workaround

https://github.com/neogenie/fastnum/issues/28
---
 Cargo.lock       |  4 ++--
 src/evaluator.rs |  2 ++
 src/units.rs     | 18 +++++-------------
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index accac65..912322e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -60,9 +60,9 @@ dependencies = [
 
 [[package]]
 name = "fastnum"
-version = "0.2.8"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86cde0c9334bfed5ced962bd7acc266e02e254d71494787e4255d8ec4f7296d4"
+checksum = "b875e26379edd7866a74cec720c6ae7bea3107aaf9fd3b14d7449d87d4c1986b"
 dependencies = [
  "autocfg",
  "bnum",
diff --git a/src/evaluator.rs b/src/evaluator.rs
index eb17b73..6212469 100644
--- a/src/evaluator.rs
+++ b/src/evaluator.rs
@@ -299,6 +299,8 @@ mod tests {
 		assert_eq!(eval_default("-1km to m"), Number::new(d!(-1000), Unit::Meter));
 		assert_eq!(eval_num("2*-3*0.5"), "-3");
 		assert_eq!(eval_num("-3^2"), "-9");
+		assert_eq!(eval_num("e^2"), "7.3890560989306502272304274605750078132");
+		assert_eq!(eval_num("e^2.5"), "12.1824939607034734380701759511679661832");
 		assert_eq!(eval_num("-1+2"), "1");
 	}
 
diff --git a/src/units.rs b/src/units.rs
index c8fa132..d095cad 100644
--- a/src/units.rs
+++ b/src/units.rs
@@ -1,4 +1,4 @@
-use fastnum::{dec128 as d, D128, D256};
+use fastnum::{dec128 as d, D128};
 use crate::Number;
 
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -754,15 +754,6 @@ pub fn modulo(left: Number, right: Number) -> Result<Number, String> {
 	}
 }
 
-fn do_pow(left: D128, right: D128) -> D128 {
-	// Do pow with d256 for higher accuracy
-	let left = D256::try_from(left.transmute()).unwrap();
-	let right = D256::try_from(right.transmute()).unwrap();
-	let result = left.pow(right);
-	let result_d128: D128 = result.transmute();
-	result_d128
-}
-
 /// Returns a [`Number`] to the power of another [`Number`]
 /// 
 /// - If you take [`Length`] to the power of [`NoType`], the result has a unit of [`Area`].
@@ -770,20 +761,21 @@ fn do_pow(left: D128, right: D128) -> D128 {
 /// - If you take [`Length`] to the power of [`Area`], the result has a unit of [`Volume`]
 /// - etc.
 pub fn pow(left: Number, right: Number) -> Result<Number, String> {
+	// I tried converting `right` to use powi, but somehow that was slower
 	let lcat = left.unit.category();
 	let rcat = left.unit.category();
 	if left.unit == NoUnit && right.unit == NoUnit {
 		// 3 ^ 2
-		Ok(Number::new(do_pow(left.value, right.value), left.unit))
+		Ok(Number::new(left.value.pow(right.value), left.unit))
 	} else if right.value == d!(1) && right.unit == NoUnit {
 		Ok(left)
 	} else if lcat == Length && right.unit == NoUnit && right.value == d!(2) {
 		// x km ^ 2
-		let result = do_pow(left.value * left.unit.weight(), right.value);
+		let result = (left.value * left.unit.weight()).pow(right.value);
 		Ok(to_ideal_unit(Number::new(result, SquareMillimeter)))
 	} else if lcat == Length && right.unit == NoUnit && right.value == d!(3) {
 		// x km ^ 3
-		let result = do_pow(left.value * left.unit.weight(), right.value);
+		let result = (left.value * left.unit.weight()).pow(right.value);
 		Ok(to_ideal_unit(Number::new(result, CubicMillimeter)))
 	} else if lcat == Length && rcat == Length && right.value == d!(1) {
 		// x km ^ 1 km