diff --git a/src/na.rs b/src/na.rs
index b6b56643..504fd983 100644
--- a/src/na.rs
+++ b/src/na.rs
@@ -4,8 +4,9 @@ use std::num::{Zero, One};
 pub use traits::{
     Absolute,
     AbsoluteRotate,
-    AlgebraicVec,
-    AlgebraicVecExt,
+    ApproxEq,
+    RealVec,
+    RealVecExt,
     Basis,
     Cast,
     Col,
@@ -431,19 +432,19 @@ pub fn sub_dot<V: Dot<N>, N>(a: &V, b: &V, c: &V) -> N {
 
 /// Computes the L2 norm of a vector.
 #[inline(always)]
-pub fn norm<V: Norm<N>, N: Algebraic>(v: &V) -> N {
+pub fn norm<V: Norm<N>, N: Real>(v: &V) -> N {
     Norm::norm(v)
 }
 
 /// Computes the squared L2 norm of a vector.
 #[inline(always)]
-pub fn sqnorm<V: Norm<N>, N: Algebraic>(v: &V) -> N {
+pub fn sqnorm<V: Norm<N>, N: Real>(v: &V) -> N {
     Norm::sqnorm(v)
 }
 
 /// Gets the normalized version of a vector.
 #[inline(always)]
-pub fn normalize<V: Norm<N>, N: Algebraic>(v: &V) -> V {
+pub fn normalize<V: Norm<N>, N: Real>(v: &V) -> V {
     Norm::normalize_cpy(v)
 }
 
@@ -508,6 +509,21 @@ pub fn sample_sphere<V: UniformSphereSample>(f: |V| -> ()) {
 //
 //
 
+/*
+ * AproxEq<N>
+ */
+/// Tests approximate equality.
+#[inline(always)]
+pub fn approx_eq<T: ApproxEq<N>, N>(a: &T, b: &T) -> bool {
+    ApproxEq::approx_eq(a, b)
+}
+
+/// Tests approximate equality using a custom epsilon.
+#[inline(always)]
+pub fn approx_eq_eps<T: ApproxEq<N>, N>(a: &T, b: &T, eps: &N) -> bool {
+    ApproxEq::approx_eq_eps(a, b, eps)
+}
+
 
 /*
  * Absolute<A>
diff --git a/src/structs/dmat.rs b/src/structs/dmat.rs
index 586a3886..bca8a2b9 100644
--- a/src/structs/dmat.rs
+++ b/src/structs/dmat.rs
@@ -6,7 +6,7 @@ use std::rand::Rand;
 use std::rand;
 use std::num::{One, Zero};
 use std::vec;
-use std::cmp::ApproxEq;
+use traits::operations::ApproxEq;
 use std::util;
 use structs::dvec::{DVec, DVecMulRhs};
 use traits::operations::{Inv, Transpose, Mean, Cov};
@@ -499,25 +499,22 @@ impl<N: Clone + Num + Cast<f32> + DMatDivRhs<N, DMat<N>> + ToStr > Cov<DMat<N>>
 
 impl<N: ApproxEq<N>> ApproxEq<N> for DMat<N> {
     #[inline]
-    fn approx_epsilon() -> N {
-        fail!("This function cannot work due to a compiler bug.")
-        // let res: N = ApproxEq::<N>::approx_epsilon();
-
-        // res
+    fn approx_epsilon(_: Option<DMat<N>>) -> N {
+        ApproxEq::approx_epsilon(None::<N>)
     }
 
     #[inline]
-    fn approx_eq(&self, other: &DMat<N>) -> bool {
-        let mut zip = self.mij.iter().zip(other.mij.iter());
+    fn approx_eq(a: &DMat<N>, b: &DMat<N>) -> bool {
+        let mut zip = a.mij.iter().zip(b.mij.iter());
 
-        zip.all(|(a, b)| a.approx_eq(b))
+        zip.all(|(a, b)| ApproxEq::approx_eq(a, b))
     }
 
     #[inline]
-    fn approx_eq_eps(&self, other: &DMat<N>, epsilon: &N) -> bool {
-        let mut zip = self.mij.iter().zip(other.mij.iter());
+    fn approx_eq_eps(a: &DMat<N>, b: &DMat<N>, epsilon: &N) -> bool {
+        let mut zip = a.mij.iter().zip(b.mij.iter());
 
-        zip.all(|(a, b)| a.approx_eq_eps(b, epsilon))
+        zip.all(|(a, b)| ApproxEq::approx_eq_eps(a, b, epsilon))
     }
 }
 
diff --git a/src/structs/dvec.rs b/src/structs/dvec.rs
index 935980e3..a2711c2f 100644
--- a/src/structs/dvec.rs
+++ b/src/structs/dvec.rs
@@ -2,12 +2,12 @@
 
 #[allow(missing_doc)]; // we hide doc to not have to document the $trhs double dispatch trait.
 
-use std::num::{Zero, One, Algebraic};
+use std::num::{Zero, One, Real};
 use std::rand::Rand;
 use std::rand;
 use std::vec;
 use std::vec::{VecIterator, VecMutIterator};
-use std::cmp::ApproxEq;
+use traits::operations::ApproxEq;
 use std::iter::FromIterator;
 use traits::geometry::{Dot, Norm};
 use traits::structure::{Iterable, IterableMut};
@@ -177,7 +177,7 @@ impl<N> FromIterator<N> for DVec<N> {
     }
 }
 
-impl<N: Clone + Num + Algebraic + ApproxEq<N> + DVecMulRhs<N, DVec<N>>> DVec<N> {
+impl<N: Clone + Num + Real + ApproxEq<N> + DVecMulRhs<N, DVec<N>>> DVec<N> {
     /// Computes the canonical basis for the given dimension. A canonical basis is a set of
     /// vectors, mutually orthogonal, with all its component equal to 0.0 exept one which is equal
     /// to 1.0.
@@ -220,7 +220,7 @@ impl<N: Clone + Num + Algebraic + ApproxEq<N> + DVecMulRhs<N, DVec<N>>> DVec<N>
                 elt = elt - v * Dot::dot(&elt, v)
             };
 
-            if !Norm::sqnorm(&elt).approx_eq(&Zero::zero()) {
+            if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &Zero::zero()) {
                 res.push(Norm::normalize_cpy(&elt));
             }
         }
@@ -284,7 +284,7 @@ impl<N: Num + Clone> Dot<N> for DVec<N> {
     } 
 }
 
-impl<N: Num + Algebraic + Clone> Norm<N> for DVec<N> {
+impl<N: Num + Real + Clone> Norm<N> for DVec<N> {
     #[inline]
     fn sqnorm(v: &DVec<N>) -> N {
         Dot::dot(v, v)
@@ -318,25 +318,22 @@ impl<N: Num + Algebraic + Clone> Norm<N> for DVec<N> {
 
 impl<N: ApproxEq<N>> ApproxEq<N> for DVec<N> {
     #[inline]
-    fn approx_epsilon() -> N {
-        fail!("Fix me.")
-        // let res: N = ApproxEq::<N>::approx_epsilon();
-
-        // res
+    fn approx_epsilon(_: Option<DVec<N>>) -> N {
+        ApproxEq::approx_epsilon(None::<N>)
     }
 
     #[inline]
-    fn approx_eq(&self, other: &DVec<N>) -> bool {
-        let mut zip = self.at.iter().zip(other.at.iter());
+    fn approx_eq(a: &DVec<N>, b: &DVec<N>) -> bool {
+        let mut zip = a.at.iter().zip(b.at.iter());
 
-        zip.all(|(a, b)| a.approx_eq(b))
+        zip.all(|(a, b)| ApproxEq::approx_eq(a, b))
     }
 
     #[inline]
-    fn approx_eq_eps(&self, other: &DVec<N>, epsilon: &N) -> bool {
-        let mut zip = self.at.iter().zip(other.at.iter());
+    fn approx_eq_eps(a: &DVec<N>, b: &DVec<N>, epsilon: &N) -> bool {
+        let mut zip = a.at.iter().zip(b.at.iter());
 
-        zip.all(|(a, b)| a.approx_eq_eps(b, epsilon))
+        zip.all(|(a, b)| ApproxEq::approx_eq_eps(a, b, epsilon))
     }
 }
 
diff --git a/src/structs/iso.rs b/src/structs/iso.rs
index c73cbd25..c69d93b2 100644
--- a/src/structs/iso.rs
+++ b/src/structs/iso.rs
@@ -6,7 +6,7 @@ use std::num::{Zero, One};
 use std::rand::{Rand, Rng};
 use structs::mat::{Mat3, Mat4, Mat5};
 use traits::structure::{Cast, Dim, Col};
-use traits::operations::{Inv};
+use traits::operations::{Inv, ApproxEq};
 use traits::geometry::{RotationMatrix, Rotation, Rotate, AbsoluteRotate, Transform, Transformation,
                        Translate, Translation, ToHomogeneous};
 
@@ -51,7 +51,7 @@ pub struct Iso4<N> {
     translation: Vec4<N>
 }
 
-impl<N: Clone + Num + Algebraic> Iso3<N> {
+impl<N: Clone + Num + Real> Iso3<N> {
     /// Reorient and translate this transformation such that its local `x` axis points to a given
     /// direction.  Note that the usually known `look_at` function does the same thing but with the
     /// `z` axis. See `look_at_z` for that.
diff --git a/src/structs/iso_macros.rs b/src/structs/iso_macros.rs
index bdf0cb2b..149290d6 100644
--- a/src/structs/iso_macros.rs
+++ b/src/structs/iso_macros.rs
@@ -2,7 +2,7 @@
 
 macro_rules! iso_impl(
     ($t: ident, $submat: ident, $subvec: ident, $subrotvec: ident) => (
-        impl<N: Clone + Trigonometric + Algebraic + Num> $t<N> {
+        impl<N: Clone + Real + Real + Num> $t<N> {
             /// Creates a new isometry from a rotation matrix and a vector.
             #[inline]
             pub fn new(translation: $subvec<N>, rotation: $subrotvec<N>) -> $t<N> {
@@ -26,7 +26,7 @@ macro_rules! iso_impl(
 
 macro_rules! rotation_matrix_impl(
     ($t: ident, $trot: ident, $tlv: ident, $tav: ident) => (
-        impl<N: Cast<f32> + Algebraic + Trigonometric + Num + Clone>
+        impl<N: Cast<f32> + Real + Real + Num + Clone>
         RotationMatrix<$tlv<N>, $tav<N>, $trot<N>> for $t<N> {
             #[inline]
             fn to_rot_mat(&self) -> $trot<N> {
@@ -50,7 +50,7 @@ macro_rules! dim_impl(
 
 macro_rules! one_impl(
     ($t: ident) => (
-        impl<N: Trigonometric + Algebraic + Num + Clone> One for $t<N> {
+        impl<N: Real + Real + Num + Clone> One for $t<N> {
             #[inline]
             fn one() -> $t<N> {
                 $t::new_with_rotmat(Zero::zero(), One::one())
@@ -61,7 +61,7 @@ macro_rules! one_impl(
 
 macro_rules! iso_mul_iso_impl(
     ($t: ident, $tmul: ident) => (
-        impl<N: Num + Trigonometric + Algebraic + Clone> $tmul<N, $t<N>> for $t<N> {
+        impl<N: Num + Real + Real + Clone> $tmul<N, $t<N>> for $t<N> {
             #[inline]
             fn binop(left: &$t<N>, right: &$t<N>) -> $t<N> {
                 $t::new_with_rotmat(
@@ -96,7 +96,7 @@ macro_rules! vec_mul_iso_impl(
 
 macro_rules! translation_impl(
     ($t: ident, $tv: ident) => (
-        impl<N: Trigonometric + Num + Algebraic + Clone> Translation<$tv<N>> for $t<N> {
+        impl<N: Real + Num + Real + Clone> Translation<$tv<N>> for $t<N> {
             #[inline]
             fn translation(&self) -> $tv<N> {
                 self.translation.clone()
@@ -153,7 +153,7 @@ macro_rules! translate_impl(
 
 macro_rules! rotation_impl(
     ($t: ident, $trot: ident, $tav: ident) => (
-        impl<N: Cast<f32> + Num + Trigonometric + Algebraic + Clone> Rotation<$tav<N>> for $t<N> {
+        impl<N: Cast<f32> + Num + Real + Real + Clone> Rotation<$tav<N>> for $t<N> {
             #[inline]
             fn rotation(&self) -> $tav<N> {
                 self.rotation.rotation()
@@ -220,7 +220,7 @@ macro_rules! rotate_impl(
 
 macro_rules! transformation_impl(
     ($t: ident) => (
-        impl<N: Num + Trigonometric + Algebraic + Clone> Transformation<$t<N>> for $t<N> {
+        impl<N: Num + Real + Real + Clone> Transformation<$t<N>> for $t<N> {
             fn transformation(&self) -> $t<N> {
                 self.clone()
             }
@@ -315,21 +315,20 @@ macro_rules! approx_eq_impl(
     ($t: ident) => (
         impl<N: ApproxEq<N>> ApproxEq<N> for $t<N> {
             #[inline]
-            fn approx_epsilon() -> N {
-                fail!("approx_epsilon is broken since rust revision 8693943676487c01fa09f5f3daf0df6a1f71e24d.")
-                // ApproxEq::<N>::approx_epsilon()
+            fn approx_epsilon(_: Option<$t<N>>) -> N {
+                ApproxEq::approx_epsilon(None::<N>)
             }
 
             #[inline]
-            fn approx_eq(&self, other: &$t<N>) -> bool {
-                self.rotation.approx_eq(&other.rotation) &&
-                    self.translation.approx_eq(&other.translation)
+            fn approx_eq(a: &$t<N>, b: &$t<N>) -> bool {
+                ApproxEq::approx_eq(&a.rotation, &b.rotation) &&
+                    ApproxEq::approx_eq(&a.translation, &b.translation)
             }
 
             #[inline]
-            fn approx_eq_eps(&self, other: &$t<N>, epsilon: &N) -> bool {
-                self.rotation.approx_eq_eps(&other.rotation, epsilon) &&
-                    self.translation.approx_eq_eps(&other.translation, epsilon)
+            fn approx_eq_eps(a: &$t<N>, b: &$t<N>, epsilon: &N) -> bool {
+                ApproxEq::approx_eq_eps(&a.rotation, &b.rotation, epsilon) &&
+                    ApproxEq::approx_eq_eps(&a.translation, &b.translation, epsilon)
             }
         }
     )
@@ -337,7 +336,7 @@ macro_rules! approx_eq_impl(
 
 macro_rules! rand_impl(
     ($t: ident) => (
-        impl<N: Rand + Clone + Trigonometric + Algebraic + Num> Rand for $t<N> {
+        impl<N: Rand + Clone + Real + Real + Num> Rand for $t<N> {
             #[inline]
             fn rand<R: Rng>(rng: &mut R) -> $t<N> {
                 $t::new(rng.gen(), rng.gen())
diff --git a/src/structs/mat.rs b/src/structs/mat.rs
index baf2c1c5..6bafa927 100644
--- a/src/structs/mat.rs
+++ b/src/structs/mat.rs
@@ -4,7 +4,7 @@
 
 use std::cast;
 use std::num::{One, Zero};
-use std::cmp::ApproxEq;
+use traits::operations::ApproxEq;
 use std::vec::{VecIterator, VecMutIterator};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4, Vec5, Vec6, Vec1MulRhs, Vec4MulRhs,
                    Vec5MulRhs, Vec6MulRhs};
diff --git a/src/structs/mat_macros.rs b/src/structs/mat_macros.rs
index 61b745af..8abf00c5 100644
--- a/src/structs/mat_macros.rs
+++ b/src/structs/mat_macros.rs
@@ -449,23 +449,22 @@ macro_rules! approx_eq_impl(
   ($t: ident) => (
     impl<N: ApproxEq<N>> ApproxEq<N> for $t<N> {
         #[inline]
-        fn approx_epsilon() -> N {
-            fail!("approx_epsilon is broken since rust revision 8693943676487c01fa09f5f3daf0df6a1f71e24d.")
-            // ApproxEq::<N>::approx_epsilon()
+        fn approx_epsilon(_: Option<$t<N>>) -> N {
+            ApproxEq::approx_epsilon(None::<N>)
         }
 
         #[inline]
-        fn approx_eq(&self, other: &$t<N>) -> bool {
-            let mut zip = self.iter().zip(other.iter());
+        fn approx_eq(a: &$t<N>, b: &$t<N>) -> bool {
+            let mut zip = a.iter().zip(b.iter());
 
-            zip.all(|(a, b)| a.approx_eq(b))
+            zip.all(|(a, b)| ApproxEq::approx_eq(a, b))
         }
 
         #[inline]
-        fn approx_eq_eps(&self, other: &$t<N>, epsilon: &N) -> bool {
-            let mut zip = self.iter().zip(other.iter());
+        fn approx_eq_eps(a: &$t<N>, b: &$t<N>, epsilon: &N) -> bool {
+            let mut zip = a.iter().zip(b.iter());
 
-            zip.all(|(a, b)| a.approx_eq_eps(b, epsilon))
+            zip.all(|(a, b)| ApproxEq::approx_eq_eps(a, b, epsilon))
         }
     }
   )
diff --git a/src/structs/rot.rs b/src/structs/rot.rs
index e0684884..e7daa12f 100644
--- a/src/structs/rot.rs
+++ b/src/structs/rot.rs
@@ -7,7 +7,7 @@ use std::rand::{Rand, Rng};
 use traits::geometry::{Rotate, Rotation, AbsoluteRotate, RotationMatrix, Transform, ToHomogeneous,
                        Norm, Cross};
 use traits::structure::{Cast, Dim, Row, Col};
-use traits::operations::{Absolute, Inv, Transpose};
+use traits::operations::{Absolute, Inv, Transpose, ApproxEq};
 use structs::vec::{Vec1, Vec2, Vec3, Vec4, Vec2MulRhs, Vec3MulRhs, Vec4MulRhs};
 use structs::mat::{Mat2, Mat3, Mat4, Mat5};
 
@@ -20,7 +20,7 @@ pub struct Rot2<N> {
     priv submat: Mat2<N>
 }
 
-impl<N: Clone + Trigonometric + Neg<N>> Rot2<N> {
+impl<N: Clone + Real + Neg<N>> Rot2<N> {
     /// Builds a 2 dimensional rotation matrix from an angle in radian.
     pub fn new(angle: Vec1<N>) -> Rot2<N> {
         let (sia, coa) = angle.x.sin_cos();
@@ -31,7 +31,7 @@ impl<N: Clone + Trigonometric + Neg<N>> Rot2<N> {
     }
 }
 
-impl<N: Trigonometric + Num + Clone>
+impl<N: Real + Num + Clone>
 Rotation<Vec1<N>> for Rot2<N> {
     #[inline]
     fn rotation(&self) -> Vec1<N> {
@@ -69,7 +69,7 @@ Rotation<Vec1<N>> for Rot2<N> {
     }
 }
 
-impl<N: Clone + Rand + Trigonometric + Neg<N>> Rand for Rot2<N> {
+impl<N: Clone + Rand + Real + Neg<N>> Rand for Rot2<N> {
     #[inline]
     fn rand<R: Rng>(rng: &mut R) -> Rot2<N> {
         Rot2::new(rng.gen())
@@ -99,7 +99,7 @@ pub struct Rot3<N> {
 }
 
 
-impl<N: Clone + Trigonometric + Num + Algebraic> Rot3<N> {
+impl<N: Clone + Real + Num + Real> Rot3<N> {
     /// Builds a 3 dimensional rotation matrix from an axis and an angle.
     ///
     /// # Arguments
@@ -140,7 +140,7 @@ impl<N: Clone + Trigonometric + Num + Algebraic> Rot3<N> {
     }
 }
 
-impl<N: Clone + Num + Algebraic> Rot3<N> {
+impl<N: Clone + Num + Real> Rot3<N> {
     /// Reorient this matrix such that its local `x` axis points to a given point. Note that the
     /// usually known `look_at` function does the same thing but with the `z` axis. See `look_at_z`
     /// for that.
@@ -180,7 +180,7 @@ impl<N: Clone + Num + Algebraic> Rot3<N> {
     }
 }
 
-impl<N: Clone + Trigonometric + Num + Algebraic + Cast<f32>>
+impl<N: Clone + Real + Num + Real + Cast<f32>>
 Rotation<Vec3<N>> for Rot3<N> {
     #[inline]
     fn rotation(&self) -> Vec3<N> {
@@ -245,7 +245,7 @@ Rotation<Vec3<N>> for Rot3<N> {
     }
 }
 
-impl<N: Clone + Rand + Trigonometric + Num + Algebraic>
+impl<N: Clone + Rand + Real + Num + Real>
 Rand for Rot3<N> {
     #[inline]
     fn rand<R: Rng>(rng: &mut R) -> Rot3<N> {
@@ -309,7 +309,7 @@ impl<N: Signed> AbsoluteRotate<Vec4<N>> for Rot4<N> {
     }
 }
 
-impl<N: Trigonometric + Num + Clone>
+impl<N: Real + Num + Clone>
 Rotation<Vec4<N>> for Rot4<N> {
     #[inline]
     fn rotation(&self) -> Vec4<N> {
diff --git a/src/structs/rot_macros.rs b/src/structs/rot_macros.rs
index 03353be2..b0d341f0 100644
--- a/src/structs/rot_macros.rs
+++ b/src/structs/rot_macros.rs
@@ -56,7 +56,7 @@ macro_rules! dim_impl(
 
 macro_rules! rotation_matrix_impl(
     ($t: ident, $tlv: ident, $tav: ident) => (
-        impl<N: Cast<f32> + Algebraic + Trigonometric + Num + Clone>
+        impl<N: Cast<f32> + Real + Real + Num + Clone>
         RotationMatrix<$tlv<N>, $tav<N>, $t<N>> for $t<N> {
             #[inline]
             fn to_rot_mat(&self) -> $t<N> {
@@ -201,19 +201,18 @@ macro_rules! approx_eq_impl(
     ($t: ident) => (
         impl<N: ApproxEq<N>> ApproxEq<N> for $t<N> {
             #[inline]
-            fn approx_epsilon() -> N {
-                // ApproxEq::<N>::approx_epsilon()
-                fail!("approx_epsilon is broken since rust revision 8693943676487c01fa09f5f3daf0df6a1f71e24d.")
+            fn approx_epsilon(_: Option<$t<N>>) -> N {
+                ApproxEq::approx_epsilon(None::<N>)
             }
 
             #[inline]
-            fn approx_eq(&self, other: &$t<N>) -> bool {
-                self.submat.approx_eq(&other.submat)
+            fn approx_eq(a: &$t<N>, b: &$t<N>) -> bool {
+                ApproxEq::approx_eq(&a.submat, &b.submat)
             }
 
             #[inline]
-            fn approx_eq_eps(&self, other: &$t<N>, epsilon: &N) -> bool {
-                self.submat.approx_eq_eps(&other.submat, epsilon)
+            fn approx_eq_eps(a: &$t<N>, b: &$t<N>, epsilon: &N) -> bool {
+                ApproxEq::approx_eq_eps(&a.submat, &b.submat, epsilon)
             }
         }
     )
diff --git a/src/structs/spec/vec.rs b/src/structs/spec/vec.rs
index 394d1570..38a16d08 100644
--- a/src/structs/spec/vec.rs
+++ b/src/structs/spec/vec.rs
@@ -91,7 +91,7 @@ impl<N: Clone + One + Zero + Neg<N>> Basis for Vec2<N> {
     }
 }
 
-impl<N: Clone + Ord + Algebraic + Signed> Basis for Vec3<N> {
+impl<N: Clone + Ord + Real + Signed> Basis for Vec3<N> {
     #[inline(always)]
     fn canonical_basis(f: |Vec3<N>| -> bool) {
         if !f(Vec3::new(One::one(), Zero::zero(), Zero::zero())) { return };
diff --git a/src/structs/spec/vec0.rs b/src/structs/spec/vec0.rs
index 01d2af76..384d7f64 100644
--- a/src/structs/spec/vec0.rs
+++ b/src/structs/spec/vec0.rs
@@ -1,8 +1,8 @@
 use std::cast;
-use std::num::{Zero, One, Algebraic, Bounded};
+use std::num::{Zero, One, Real, Bounded};
 use std::vec::{VecIterator, VecMutIterator};
 use std::iter::{Iterator, FromIterator};
-use std::cmp::ApproxEq;
+use traits::operations::ApproxEq;
 use traits::structure::{Iterable, IterableMut, Indexable, Basis, Dim};
 use traits::geometry::{Translation, Dot, Norm};
 use structs::vec;
@@ -159,7 +159,7 @@ impl<N: Clone + Add<N, N> + Neg<N>> Translation<vec::Vec0<N>> for vec::Vec0<N> {
     }
 }
 
-impl<N: Clone + Num + Algebraic> Norm<N> for vec::Vec0<N> {
+impl<N: Clone + Num + Real> Norm<N> for vec::Vec0<N> {
     #[inline]
     fn sqnorm(_: &vec::Vec0<N>) -> N {
         Zero::zero()
@@ -183,18 +183,17 @@ impl<N: Clone + Num + Algebraic> Norm<N> for vec::Vec0<N> {
 
 impl<N: ApproxEq<N>> ApproxEq<N> for vec::Vec0<N> {
     #[inline]
-    fn approx_epsilon() -> N {
-        fail!("approx_epsilon is broken since rust revision 8693943676487c01fa09f5f3daf0df6a1f71e24d.")
-        // ApproxEq::<N>::approx_epsilon()
+    fn approx_epsilon(_: Option<vec::Vec0<N>>) -> N {
+        ApproxEq::approx_epsilon(None::<N>)
     }
 
     #[inline]
-    fn approx_eq(&self, _: &vec::Vec0<N>) -> bool {
+    fn approx_eq(_: &vec::Vec0<N>, _: &vec::Vec0<N>) -> bool {
         true
     }
 
     #[inline]
-    fn approx_eq_eps(&self, _: &vec::Vec0<N>, _: &N) -> bool {
+    fn approx_eq_eps(_: &vec::Vec0<N>, _: &vec::Vec0<N>, _: &N) -> bool {
         true
     }
 }
diff --git a/src/structs/vec.rs b/src/structs/vec.rs
index 79d9fcd1..d0c3e54a 100644
--- a/src/structs/vec.rs
+++ b/src/structs/vec.rs
@@ -3,10 +3,10 @@
 #[allow(missing_doc)]; // we allow missing to avoid having to document the vector components.
 
 use std::cast;
-use std::num::{Zero, One, Algebraic, Bounded};
+use std::num::{Zero, One, Real, Bounded};
 use std::vec::{VecIterator, VecMutIterator};
 use std::iter::{Iterator, FromIterator};
-use std::cmp::ApproxEq;
+use traits::operations::ApproxEq;
 
 use traits::geometry::{Transform, Rotate, FromHomogeneous, ToHomogeneous, Dot, Norm,
                        Translation, Translate};
diff --git a/src/structs/vec_macros.rs b/src/structs/vec_macros.rs
index fb15ddea..cb0004eb 100644
--- a/src/structs/vec_macros.rs
+++ b/src/structs/vec_macros.rs
@@ -223,7 +223,7 @@ macro_rules! container_impl(
 
 macro_rules! basis_impl(
     ($t: ident, $trhs: ident, $dim: expr) => (
-        impl<N: Clone + Num + Algebraic + ApproxEq<N> + $trhs<N, $t<N>>> Basis for $t<N> {
+        impl<N: Clone + Num + Real + ApproxEq<N> + $trhs<N, $t<N>>> Basis for $t<N> {
             #[inline]
             fn canonical_basis(f: |$t<N>| -> bool) {
                 for i in range(0u, $dim) {
@@ -262,7 +262,7 @@ macro_rules! basis_impl(
                         elt = elt - v * Dot::dot(&elt, v)
                     };
 
-                    if !Norm::sqnorm(&elt).approx_eq(&Zero::zero()) {
+                    if !ApproxEq::approx_eq(&Norm::sqnorm(&elt), &Zero::zero()) {
                         let new_element = Norm::normalize_cpy(&elt);
 
                         if !f(new_element.clone()) { return };
@@ -433,7 +433,7 @@ macro_rules! translation_impl(
 
 macro_rules! norm_impl(
     ($t: ident, $comp0: ident $(,$compN: ident)*) => (
-        impl<N: Clone + Num + Algebraic> Norm<N> for $t<N> {
+        impl<N: Clone + Num + Real> Norm<N> for $t<N> {
             #[inline]
             fn sqnorm(v: &$t<N>) -> N {
                 Dot::dot(v, v)
@@ -496,19 +496,20 @@ macro_rules! approx_eq_impl(
     ($t: ident, $comp0: ident $(,$compN: ident)*) => (
         impl<N: ApproxEq<N>> ApproxEq<N> for $t<N> {
             #[inline]
-            fn approx_epsilon() -> N {
-                fail!("approx_epsilon is broken since rust revision 8693943676487c01fa09f5f3daf0df6a1f71e24d.")
-                // ApproxEq::<N>::approx_epsilon()
+            fn approx_epsilon(_: Option<$t<N>>) -> N {
+                ApproxEq::approx_epsilon(None::<N>)
             }
 
             #[inline]
-            fn approx_eq(&self, other: &$t<N>) -> bool {
-                self.$comp0.approx_eq(&other.$comp0) $(&& self.$compN.approx_eq(&other.$compN))*
+            fn approx_eq(a: &$t<N>, b: &$t<N>) -> bool {
+                ApproxEq::approx_eq(&a.$comp0, &b.$comp0)
+                $(&& ApproxEq::approx_eq(&a.$compN, &b.$compN))*
             }
 
             #[inline]
-            fn approx_eq_eps(&self, other: &$t<N>, eps: &N) -> bool {
-                self.$comp0.approx_eq_eps(&other.$comp0, eps) $(&& self.$compN.approx_eq_eps(&other.$compN, eps))*
+            fn approx_eq_eps(a: &$t<N>, b: &$t<N>, eps: &N) -> bool {
+                ApproxEq::approx_eq_eps(&a.$comp0, &b.$comp0, eps)
+                $(&& ApproxEq::approx_eq_eps(&a.$compN, &b.$compN, eps))*
             }
         }
     )
diff --git a/src/tests/mat.rs b/src/tests/mat.rs
index b190a884..ff423aa0 100644
--- a/src/tests/mat.rs
+++ b/src/tests/mat.rs
@@ -1,6 +1,5 @@
 use std::num::{Real, abs};
 use std::rand::random;
-use std::cmp::ApproxEq;
 use na::{Vec1, Vec3, Mat1, Mat2, Mat3, Mat4, Mat5, Mat6, Rot3, DMat, DVec, Indexable};
 use na;
 
@@ -9,7 +8,7 @@ macro_rules! test_inv_mat_impl(
     10000.times(|| {
       let randmat : $t = random();
 
-      assert!((na::inv(&randmat).unwrap() * randmat).approx_eq(&na::one()));
+      assert!(na::approx_eq(&(na::inv(&randmat).unwrap() * randmat), &na::one()));
     })
   );
 )
@@ -90,7 +89,7 @@ fn test_rotation2() {
         let randmat: na::Rot2<f64> = na::one();
         let ang    = Vec1::new(abs::<f64>(random()) % Real::pi());
 
-        assert!(na::rotation(&na::append_rotation(&randmat, &ang)).approx_eq(&ang));
+        assert!(na::approx_eq(&na::rotation(&na::append_rotation(&randmat, &ang)), &ang));
     })
 }
 
@@ -109,7 +108,7 @@ fn test_inv_rotation3() {
         let ang            = na::normalize(&dir) * (abs::<f64>(random()) % Real::pi());
         let rot            = na::append_rotation(&randmat, &ang);
 
-        assert!((na::transpose(&rot) * rot).approx_eq(&na::one()));
+        assert!(na::approx_eq(&(na::transpose(&rot) * rot), &na::one()));
     })
 }
 
@@ -125,7 +124,7 @@ fn test_mean_dmat() {
         ]
     );
 
-    assert!(na::mean(&mat).approx_eq(&DVec::from_vec(3, [4.0f64, 5.0, 6.0])));
+    assert!(na::approx_eq(&na::mean(&mat), &DVec::from_vec(3, [4.0f64, 5.0, 6.0])));
 }
 
 #[test]
@@ -152,7 +151,7 @@ fn test_cov_dmat() {
         ]
     );
 
-    assert!(na::cov(&mat).approx_eq(&expected));
+    assert!(na::approx_eq(&na::cov(&mat), &expected));
 }
 
 #[test]
diff --git a/src/tests/vec.rs b/src/tests/vec.rs
index bcd74f65..a8829f4d 100644
--- a/src/tests/vec.rs
+++ b/src/tests/vec.rs
@@ -1,5 +1,4 @@
 use std::rand::{random};
-use std::cmp::ApproxEq;
 use na::{Vec0, Vec1, Vec2, Vec3, Vec4, Vec5, Vec6};
 use na::{Mat3, Iterable, IterableMut}; // FIXME: get rid of that
 use na;
@@ -28,7 +27,7 @@ macro_rules! test_commut_dot_impl(
             let v1 : $t = random();
             let v2 : $t = random();
         
-            assert!(na::dot(&v1, &v2).approx_eq(&na::dot(&v2, &v1)));
+            assert!(na::approx_eq(&na::dot(&v1, &v2), &na::dot(&v2, &v1)));
         })
     );
 )
@@ -39,10 +38,10 @@ macro_rules! test_scalar_op_impl(
             let v1 : $t = random();
             let n  : $n = random();
         
-            assert!(((v1 * n) / n).approx_eq(&v1));
-            assert!(((v1 / n) * n).approx_eq(&v1));
-            assert!(((v1 - n) + n).approx_eq(&v1));
-            assert!(((v1 + n) - n).approx_eq(&v1));
+            assert!(na::approx_eq(&((v1 * n) / n), &v1));
+            assert!(na::approx_eq(&((v1 / n) * n), &v1));
+            assert!(na::approx_eq(&((v1 - n) + n), &v1));
+            assert!(na::approx_eq(&((v1 + n) - n), &v1));
 
             let mut v1 : $t = random();
             let v0 : $t = v1.clone();
@@ -51,7 +50,7 @@ macro_rules! test_scalar_op_impl(
             v1 = v1 * n;
             v1 = v1 / n;
         
-            assert!(v1.approx_eq(&v0));
+            assert!(na::approx_eq(&v1, &v0));
         })
     );
 )
@@ -61,12 +60,12 @@ macro_rules! test_basis_impl(
         10000.times(|| {
             na::canonical_basis(|e1: $t| {
                 na::canonical_basis(|e2: $t| {
-                    assert!(e1 == e2 || na::dot(&e1, &e2).approx_eq(&na::zero()));
+                    assert!(e1 == e2 || na::approx_eq(&na::dot(&e1, &e2), &na::zero()));
 
                     true
                 });
 
-                assert!(na::norm(&e1).approx_eq(&na::one()));
+                assert!(na::approx_eq(&na::norm(&e1), &na::one()));
 
                 true
             })
@@ -82,12 +81,12 @@ macro_rules! test_subspace_basis_impl(
 
             na::orthonormal_subspace_basis(&v1, |e1| {
                 // check vectors are orthogonal to v1
-                assert!(na::dot(&v1, &e1).approx_eq(&na::zero()));
+                assert!(na::approx_eq(&na::dot(&v1, &e1), &na::zero()));
                 // check vectors form an orthonormal basis
-                assert!(na::norm(&e1).approx_eq(&na::one()));
+                assert!(na::approx_eq(&na::norm(&e1), &na::one()));
                 // check vectors form an ortogonal basis
                 na::orthonormal_subspace_basis(&v1, |e2| {
-                    assert!(e1 == e2 || na::dot(&e1, &e2).approx_eq(&na::zero()));
+                    assert!(e1 == e2 || na::approx_eq(&na::dot(&e1, &e2), &na::zero()));
 
                     true
                 });
@@ -105,8 +104,8 @@ fn test_cross_vec3() {
         let v2 : Vec3<f64> = random();
         let v3 : Vec3<f64> = na::cross(&v1, &v2);
 
-        assert!(na::dot(&v3, &v2).approx_eq(&na::zero()));
-        assert!(na::dot(&v3, &v1).approx_eq(&na::zero()));
+        assert!(na::approx_eq(&na::dot(&v3, &v2), &na::zero()));
+        assert!(na::approx_eq(&na::dot(&v3, &v1), &na::zero()));
     })
 }
 
diff --git a/src/traits/geometry.rs b/src/traits/geometry.rs
index 1bf295e0..333f1afd 100644
--- a/src/traits/geometry.rs
+++ b/src/traits/geometry.rs
@@ -218,7 +218,7 @@ pub trait Dot<N> {
 }
 
 /// Traits of objects having an euclidian norm.
-pub trait Norm<N: Algebraic> {
+pub trait Norm<N: Real> {
     /// Computes the norm of `self`.
     #[inline]
     fn norm(v: &Self) -> N {
diff --git a/src/traits/mod.rs b/src/traits/mod.rs
index b41c4fa5..6f25caed 100644
--- a/src/traits/mod.rs
+++ b/src/traits/mod.rs
@@ -4,11 +4,11 @@ pub use self::geometry::{AbsoluteRotate, Cross, CrossMatrix, Dot, FromHomogeneou
                          Rotation, RotationMatrix, RotationWithTranslation, ToHomogeneous,
                          Transform, Transformation, Translate, Translation, UniformSphereSample};
 
-pub use self::structure::{AlgebraicVec, AlgebraicVecExt, Basis, Cast, Col, Dim, Indexable,
+pub use self::structure::{RealVec, RealVecExt, Basis, Cast, Col, Dim, Indexable,
                           Iterable, IterableMut, Mat, Row, Vec, VecExt};
 
-pub use self::operations::{Absolute, Cov, Inv, LMul, Mean, Outer, RMul, ScalarAdd, ScalarSub,
-                           Transpose};
+pub use self::operations::{Absolute, ApproxEq, Cov, Inv, LMul, Mean, Outer, RMul, ScalarAdd,
+                           ScalarSub, Transpose};
 
 pub mod geometry;
 pub mod structure;
diff --git a/src/traits/operations.rs b/src/traits/operations.rs
index 1593ee2b..d4cfc25f 100644
--- a/src/traits/operations.rs
+++ b/src/traits/operations.rs
@@ -1,5 +1,42 @@
 //! Low level operations on vectors and matrices.
 
+/// Trait for testing approximate equality
+pub trait ApproxEq<Eps> {
+    /// Default epsilon for approximation.
+    fn approx_epsilon(unused_self: Option<Self>) -> Eps;
+
+    /// Tests approximate equality using a custom epsilon.
+    fn approx_eq_eps(a: &Self, other: &Self, epsilon: &Eps) -> bool;
+
+    /// Tests approximate equality.
+    fn approx_eq(a: &Self, b: &Self) -> bool {
+        ApproxEq::approx_eq_eps(a, b, &ApproxEq::approx_epsilon(None::<Self>))
+    }
+}
+
+impl ApproxEq<f32> for f32 {
+    #[inline]
+    fn approx_epsilon(_: Option<f32>) -> f32 {
+        1.0e-6
+    }
+
+    #[inline]
+    fn approx_eq_eps(a: &f32, b: &f32, epsilon: &f32) -> bool {
+        (*a - *b).abs() < *epsilon
+    }
+}
+
+impl ApproxEq<f64> for f64 {
+    #[inline]
+    fn approx_epsilon(_: Option<f64>) -> f64 {
+        1.0e-6
+    }
+
+    #[inline]
+    fn approx_eq_eps(a: &f64, b: &f64, approx_epsilon: &f64) -> bool {
+        (*a - *b).abs() < *approx_epsilon
+    }
+}
 
 /// Trait of objects having an absolute value.
 /// This is useful if the object does not have the same type as its absolute value.
diff --git a/src/traits/structure.rs b/src/traits/structure.rs
index 1c35c4a6..deed3c9a 100644
--- a/src/traits/structure.rs
+++ b/src/traits/structure.rs
@@ -27,8 +27,8 @@ pub trait Vec<N>: Dim + Sub<Self, Self> + Add<Self, Self> + Neg<Self> + Zero + E
                   + Div<N, Self> + Dot<N> {
 }
 
-/// Trait of vector with components implementing the `Algebraic` trait.
-pub trait AlgebraicVec<N: Algebraic>: Vec<N> + Norm<N> {
+/// Trait of vector with components implementing the `Real` trait.
+pub trait RealVec<N: Real>: Vec<N> + Norm<N> {
 }
 
 /// Trait grouping uncommon, low-level and borderline (from the mathematical point of view)
@@ -39,19 +39,19 @@ pub trait VecExt<N>: Vec<N> + Indexable<uint, N> + Iterable<N> +
 
 /// Trait grouping uncommon, low-level and borderline (from the mathematical point of view)
 /// operations on vectors.
-pub trait AlgebraicVecExt<N: Algebraic>: AlgebraicVec<N> + VecExt<N> + Basis + Round { }
+pub trait RealVecExt<N: Real>: RealVec<N> + VecExt<N> + Basis + Round { }
 
 impl<N, V: Dim + Sub<V, V> + Add<V, V> + Neg<V> + Zero + Eq + Mul<N, V> + Div<N, V> + Dot<N>>
 Vec<N> for V { }
 
-impl<N: Algebraic, V: Vec<N> + Norm<N>> AlgebraicVec<N> for V { }
+impl<N: Real, V: Vec<N> + Norm<N>> RealVec<N> for V { }
 
 impl<N,
      V: Vec<N> + Indexable<uint, N> + Iterable<N> +
         UniformSphereSample + ScalarAdd<N> + ScalarSub<N> + Bounded + Orderable>
 VecExt<N> for V { }
 
-impl<N: Algebraic, V: AlgebraicVec<N> + VecExt<N> + Basis + Round> AlgebraicVecExt<N> for V { }
+impl<N: Real, V: RealVec<N> + VecExt<N> + Basis + Round> RealVecExt<N> for V { }
 
 // FIXME: return an iterator instead
 /// Traits of objects which can form a basis (typically vectors).