1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/num-traits/src/ops/mul_add.rs b/vendor/num-traits/src/ops/mul_add.rs
new file mode 100644
index 0000000..51beb55
--- /dev/null
+++ b/vendor/num-traits/src/ops/mul_add.rs
@@ -0,0 +1,149 @@
+/// Fused multiply-add. Computes `(self * a) + b` with only one rounding
+/// error, yielding a more accurate result than an unfused multiply-add.
+///
+/// Using `mul_add` can be more performant than an unfused multiply-add if
+/// the target architecture has a dedicated `fma` CPU instruction.
+///
+/// Note that `A` and `B` are `Self` by default, but this is not mandatory.
+///
+/// # Example
+///
+/// ```
+/// use std::f32;
+///
+/// let m = 10.0_f32;
+/// let x = 4.0_f32;
+/// let b = 60.0_f32;
+///
+/// // 100.0
+/// let abs_difference = (m.mul_add(x, b) - (m*x + b)).abs();
+///
+/// assert!(abs_difference <= 100.0 * f32::EPSILON);
+/// ```
+pub trait MulAdd<A = Self, B = Self> {
+    /// The resulting type after applying the fused multiply-add.
+    type Output;
+
+    /// Performs the fused multiply-add operation `(self * a) + b`
+    fn mul_add(self, a: A, b: B) -> Self::Output;
+}
+
+/// The fused multiply-add assignment operation `*self = (*self * a) + b`
+pub trait MulAddAssign<A = Self, B = Self> {
+    /// Performs the fused multiply-add assignment operation `*self = (*self * a) + b`
+    fn mul_add_assign(&mut self, a: A, b: B);
+}
+
+#[cfg(any(feature = "std", feature = "libm"))]
+impl MulAdd<f32, f32> for f32 {
+    type Output = Self;
+
+    #[inline]
+    fn mul_add(self, a: Self, b: Self) -> Self::Output {
+        <Self as crate::Float>::mul_add(self, a, b)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "libm"))]
+impl MulAdd<f64, f64> for f64 {
+    type Output = Self;
+
+    #[inline]
+    fn mul_add(self, a: Self, b: Self) -> Self::Output {
+        <Self as crate::Float>::mul_add(self, a, b)
+    }
+}
+
+macro_rules! mul_add_impl {
+    ($trait_name:ident for $($t:ty)*) => {$(
+        impl $trait_name for $t {
+            type Output = Self;
+
+            #[inline]
+            fn mul_add(self, a: Self, b: Self) -> Self::Output {
+                (self * a) + b
+            }
+        }
+    )*}
+}
+
+mul_add_impl!(MulAdd for isize i8 i16 i32 i64 i128);
+mul_add_impl!(MulAdd for usize u8 u16 u32 u64 u128);
+
+#[cfg(any(feature = "std", feature = "libm"))]
+impl MulAddAssign<f32, f32> for f32 {
+    #[inline]
+    fn mul_add_assign(&mut self, a: Self, b: Self) {
+        *self = <Self as crate::Float>::mul_add(*self, a, b)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "libm"))]
+impl MulAddAssign<f64, f64> for f64 {
+    #[inline]
+    fn mul_add_assign(&mut self, a: Self, b: Self) {
+        *self = <Self as crate::Float>::mul_add(*self, a, b)
+    }
+}
+
+macro_rules! mul_add_assign_impl {
+    ($trait_name:ident for $($t:ty)*) => {$(
+        impl $trait_name for $t {
+            #[inline]
+            fn mul_add_assign(&mut self, a: Self, b: Self) {
+                *self = (*self * a) + b
+            }
+        }
+    )*}
+}
+
+mul_add_assign_impl!(MulAddAssign for isize i8 i16 i32 i64 i128);
+mul_add_assign_impl!(MulAddAssign for usize u8 u16 u32 u64 u128);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn mul_add_integer() {
+        macro_rules! test_mul_add {
+            ($($t:ident)+) => {
+                $(
+                    {
+                        let m: $t = 2;
+                        let x: $t = 3;
+                        let b: $t = 4;
+
+                        assert_eq!(MulAdd::mul_add(m, x, b), (m*x + b));
+                    }
+                )+
+            };
+        }
+
+        test_mul_add!(usize u8 u16 u32 u64 isize i8 i16 i32 i64);
+    }
+
+    #[test]
+    #[cfg(feature = "std")]
+    fn mul_add_float() {
+        macro_rules! test_mul_add {
+            ($($t:ident)+) => {
+                $(
+                    {
+                        use core::$t;
+
+                        let m: $t = 12.0;
+                        let x: $t = 3.4;
+                        let b: $t = 5.6;
+
+                        let abs_difference = (MulAdd::mul_add(m, x, b) - (m*x + b)).abs();
+
+                        assert!(abs_difference <= 46.4 * $t::EPSILON);
+                    }
+                )+
+            };
+        }
+
+        test_mul_add!(f32 f64);
+    }
+}