Basis trait now uses internal iterators to avoid allocations.

src/tests/vec.rs

@@ -79,15 +79,13 @@ macro_rules! test_basis_impl(
   ($t: ty) => (
     for 10000.times
     {
-      let basis = Basis::canonical_basis::<$t>();
+      do Basis::canonical_basis::<$t> |e1|
+      {
+        do Basis::canonical_basis::<$t> |e2|
+        { assert!(e1 == e2 || e1.dot(&e2).approx_eq(&Zero::zero())) }
 
-      // check vectors form an ortogonal basis
-      assert!(
-        do basis.iter().zip(basis.iter()).all
-        |(e1, e2)| { e1 == e2 || e1.dot(e2).approx_eq(&Zero::zero()) }
-      );
-      // check vectors form an orthonormal basis
-      assert!(basis.iter().all(|e| e.norm().approx_eq(&One::one())));
+        assert!(e1.norm().approx_eq(&One::one()));
+      }
     }
   );
 )
@@ -98,17 +96,17 @@ macro_rules! test_subspace_basis_impl(
     {
       let v : $t   = random();
       let v1       = v.normalized();
-      let subbasis = v1.orthogonal_subspace_basis();
 
-      // check vectors are orthogonal to v1
-      assert!(subbasis.iter().all(|e| v1.dot(e).approx_eq(&Zero::zero())));
-      // check vectors form an ortogonal basis
-      assert!(
-        do subbasis.iter().zip(subbasis.iter()).all
-           |(e1, e2)| { e1 == e2 || e1.dot(e2).approx_eq(&Zero::zero()) }
-      );
-      // check vectors form an orthonormal basis
-      assert!(subbasis.iter().all(|e| e.norm().approx_eq(&One::one())));
+      do v1.orthonormal_subspace_basis() |e1|
+      {
+        // check vectors are orthogonal to v1
+        assert!(v1.dot(&e1).approx_eq(&Zero::zero()));
+        // check vectors form an orthonormal basis
+        assert!(e1.norm().approx_eq(&One::one()));
+        // check vectors form an ortogonal basis
+        do v1.orthonormal_subspace_basis() |e2|
+        { assert!(e1 == e2 || e1.dot(&e2).approx_eq(&Zero::zero())) }
+      }
     }
   );
 )

src/traits/basis.rs

@@ -1,8 +1,7 @@
 pub trait Basis
 {
   /// Computes the canonical basis of the space in which this object lives.
-  // FIXME: need type-associated values
-  // FIXME: this will make allocations… this is bad
-  fn canonical_basis()                -> ~[Self];
-  fn orthogonal_subspace_basis(&self) -> ~[Self];
+  // FIXME: implement the for loop protocol?
+  fn canonical_basis(&fn(Self));
+  fn orthonormal_subspace_basis(&self, &fn(Self));
 }

src/vec_impl.rs

@@ -88,27 +88,23 @@ macro_rules! basis_impl(
   ($t: ident, $dim: expr) => (
     impl<N: Copy + DivisionRing + Algebraic + ApproxEq<N>> Basis for $t<N>
     {
-      pub fn canonical_basis() -> ~[$t<N>]
+      pub fn canonical_basis(f: &fn($t<N>))
       {
-        let mut res : ~[$t<N>] = ~[];
-    
         for iterate(0u, $dim) |i|
         {
           let mut basis_element : $t<N> = Zero::zero();
     
           basis_element.at[i] = One::one();
     
-          res.push(basis_element);
+          f(basis_element);
         }
-    
-        res
       }
     
-      pub fn orthogonal_subspace_basis(&self) -> ~[$t<N>]
+      pub fn orthonormal_subspace_basis(&self, f: &fn($t<N>))
       {
         // compute the basis of the orthogonal subspace using Gram-Schmidt
         // orthogonalization algorithm
-        let mut res : ~[$t<N>] = ~[];
+        let mut basis: ~[$t<N>] = ~[];
     
         for iterate(0u, $dim) |i|
         {
@@ -116,21 +112,25 @@ macro_rules! basis_impl(
     
           basis_element.at[i] = One::one();
     
-          if res.len() == $dim - 1
+          if basis.len() == $dim - 1
           { break; }
     
           let mut elt = copy basis_element;
     
           elt = elt - self.scalar_mul(&basis_element.dot(self));
     
-          for res.iter().advance |v|
+          for basis.iter().advance |v|
           { elt = elt - v.scalar_mul(&elt.dot(v)) };
     
           if !elt.sqnorm().approx_eq(&Zero::zero())
-          { res.push(elt.normalized()); }
-        }
+          {
+            let new_element = elt.normalized();
 
-        res
+            f(copy new_element);
+
+            basis.push(new_element);
+          }
+        }
       }
     }
   )

src/vec_spec.rs

@@ -27,44 +27,42 @@ impl<N: Mul<N, N> + Sub<N, N>> Cross<Vec3<N>> for Vec3<N>
 
 impl<N: One> Basis for Vec1<N>
 {
-  #[inline]
-  fn canonical_basis() -> ~[Vec1<N>]
-  { ~[ Vec1::new([One::one()]) ] } // FIXME: this should be static
+  #[inline(always)]
+  fn canonical_basis(f: &fn(Vec1<N>))
+  { f(Vec1::new([One::one()])) }
 
-  #[inline]
-  fn orthogonal_subspace_basis(&self) -> ~[Vec1<N>]
-  { ~[] }
+  #[inline(always)]
+  fn orthonormal_subspace_basis(&self, _: &fn(Vec1<N>))
+  { }
 }
 
 impl<N: Copy + One + Zero + Neg<N>> Basis for Vec2<N>
 {
   #[inline]
-  fn canonical_basis()     -> ~[Vec2<N>]
+  fn canonical_basis(f: &fn(Vec2<N>))
   {
-    // FIXME: this should be static
-    ~[ Vec2::new([One::one(), Zero::zero()]),
-       Vec2::new([Zero::zero(), One::one()]) ]
+    f(Vec2::new([One::one(), Zero::zero()]));
+    f(Vec2::new([Zero::zero(), One::one()]));
   }
 
   #[inline]
-  fn orthogonal_subspace_basis(&self) -> ~[Vec2<N>]
-  { ~[ Vec2::new([-self.at[1], copy self.at[0]]) ] }
+  fn orthonormal_subspace_basis(&self, f: &fn(Vec2<N>))
+  { f(Vec2::new([-self.at[1], copy self.at[0]])) }
 }
 
 impl<N: Copy + DivisionRing + Ord + Algebraic>
 Basis for Vec3<N>
 {
-  #[inline]
-  fn canonical_basis() -> ~[Vec3<N>]
+  #[inline(always)]
+  fn canonical_basis(f: &fn(Vec3<N>))
   {
-    // FIXME: this should be static
-    ~[ Vec3::new([One::one(), Zero::zero(), Zero::zero()]),
-       Vec3::new([Zero::zero(), One::one(), Zero::zero()]),
-       Vec3::new([Zero::zero(), Zero::zero(), One::one()]) ]
+    f(Vec3::new([One::one(), Zero::zero(), Zero::zero()]));
+    f(Vec3::new([Zero::zero(), One::one(), Zero::zero()]));
+    f(Vec3::new([Zero::zero(), Zero::zero(), One::one()]));
   }
 
-  #[inline]
-  fn orthogonal_subspace_basis(&self) -> ~[Vec3<N>]
+  #[inline(always)]
+  fn orthonormal_subspace_basis(&self, f: &fn(Vec3<N>))
   {
       let a = 
         if abs(copy self.at[0]) > abs(copy self.at[1])
@@ -72,6 +70,7 @@ Basis for Vec3<N>
         else
         { Vec3::new([Zero::zero(), -self.at[2], copy self.at[1]]).normalized() };
 
-      ~[ a.cross(self), a ]
+      f(a.cross(self));
+      f(a);
   }
 }