Merge pull request #33 from tekkac/fix/sin-fast-bugfix

Fix: sin fast bugfix
influenceth · Apr 15, 2024 · 4e6bd52 · 4e6bd52
2 parents adf7008 + 484b2a5
commit 4e6bd52
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Showing 5 changed files with 54 additions and 11 deletions.
diff --git a/src/f128/math/lut.cairo b/src/f128/math/lut.cairo
@@ -917,12 +917,12 @@ fn sin(a: u128) -> (u128, u128, u128) {
                     if slot == 159 {
                         return (17996860841160351744, 15274735031373064192, 15337907143211554816);
                     }
-                    if slot == 160 {
-                        return (18110048645192806400, 15337907143211554816, 15400501791515123712);
-                    }
                 }
             } else {
                 if slot < 176 {
+                    if slot == 160 {
+                        return (18110048645192806400, 15337907143211554816, 15400501791515123712);
+                    }
                     if slot == 161 {
                         return (18223236449225261056, 15400501791515123712, 15462516619630641152);
                     }

diff --git a/src/f128/math/trig.cairo b/src/f128/math/trig.cairo
@@ -169,7 +169,7 @@ fn sin_fast(a: Fixed) -> Fixed {
     }
 
     let (start, low, high) = lut::sin(partial_rem);
-    let partial_step = FixedTrait::new(partial_rem - start, false)
+    let partial_step = (FixedTrait::new(partial_rem, false) - FixedTrait::new(start, false))
         / FixedTrait::new(113187804032455040, false);
     let res = partial_step * (FixedTrait::new(high, false) - FixedTrait::new(low, false))
         + FixedTrait::new(low, false);
@@ -439,6 +439,27 @@ mod tests {
         ); // 0.9613974918793389
     }
 
+    #[test]
+    #[available_gas(90_000_000_000)]
+    fn test_compare_sin() {
+        let error = Option::Some(184467440737095);
+
+        let MAX: u128 = 256 * 4;
+        let mut n: u128 = 0;
+        loop {
+            if n == MAX {
+                break;
+            }
+            let a = FixedTrait::new(n * 113187804032455040 * 256 / MAX + 1, false);
+            let sin1 = sin_fast(a);
+            let sin2 = sin(a);
+
+            assert_precise(sin1, sin2.mag.into(), 'invalid sin', error);
+
+            n += 1;
+        }
+    }
+
     #[test]
     #[available_gas(8000000)]
     fn test_tan() {

diff --git a/src/f64/math/lut.cairo b/src/f64/math/lut.cairo
@@ -719,12 +719,12 @@ fn sin(a: u64) -> (u64, u64, u64) {
                     if slot == 159 {
                         return (4190220693, 3556426389, 3571134792);
                     }
-                    if slot == 160 {
-                        return (4216574283, 3571134792, 3585708745);
-                    }
                 }
             } else {
                 if slot < 176 {
+                    if slot == 160 {
+                        return (4216574283, 3571134792, 3585708745);
+                    }
                     if slot == 161 {
                         return (4242927872, 3585708745, 3600147697);
                     }

diff --git a/src/f64/math/trig.cairo b/src/f64/math/trig.cairo
@@ -163,7 +163,7 @@ fn sin_fast(a: Fixed) -> Fixed {
     }
 
     let (start, low, high) = lut::sin(partial_rem);
-    let partial_step = FixedTrait::new(partial_rem - start, false)
+    let partial_step = (FixedTrait::new(partial_rem, false) - FixedTrait::new(start, false))
         / FixedTrait::new(26353589, false);
     let res = partial_step * (FixedTrait::new(high, false) - FixedTrait::new(low, false))
         + FixedTrait::new(low, false);
@@ -446,6 +446,28 @@ mod tests {
         assert_precise(sin_fast(a), 4129170786, 'invalid -17', error); // 0.9613974918793389
     }
 
+    #[test]
+    #[available_gas(9_000_000_000)]
+    fn test_compare_sin() {
+        let error = Option::Some(42950); // 1e-5
+        let pi = FixedTrait::new(PI, false);
+
+        let MAX: u64 = 256 * 4;
+        let mut n: u64 = 0;
+        loop {
+            if n == MAX {
+                break;
+            }
+            let a = FixedTrait::new(n * 26353589 * 256 / MAX + 1, false);
+            let sin1 = sin_fast(a);
+            let sin2 = sin(a);
+
+            assert_precise(sin1, sin2.mag.into(), 'invalid sin', error);
+
+            n += 1;
+        }
+    }
+
     #[test]
     #[available_gas(8000000)]
     fn test_tan() {

diff --git a/src/math/lut.cairo b/src/math/lut.cairo
@@ -917,12 +917,12 @@ fn sin(a: u128) -> (u128, u128, u128) {
                     if slot == 159 {
                         return (17996860841160351744, 15274735031373064192, 15337907143211554816);
                     }
-                    if slot == 160 {
-                        return (18110048645192806400, 15337907143211554816, 15400501791515123712);
-                    }
                 }
             } else {
                 if slot < 176 {
+                    if slot == 160 {
+                        return (18110048645192806400, 15337907143211554816, 15400501791515123712);
+                    }
                     if slot == 161 {
                         return (18223236449225261056, 15400501791515123712, 15462516619630641152);
                     }