diff --git a/Makefile b/Makefile
index 8c990b8f..68005dea 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ nalgebra_lib_path=lib
 nalgebra_doc_path=doc
 all:
 	mkdir -p $(nalgebra_lib_path)
-	rust build src/nalgebra.rc --out-dir $(nalgebra_lib_path)
+	rust build src/nalgebra.rc --out-dir $(nalgebra_lib_path) --opt-level 3
 
 test:
 	mkdir -p $(nalgebra_lib_path)
diff --git a/src/adaptors/rotmat.rs b/src/adaptors/rotmat.rs
index 8ff29df5..5e65ebf3 100644
--- a/src/adaptors/rotmat.rs
+++ b/src/adaptors/rotmat.rs
@@ -6,7 +6,7 @@ use traits::dim::Dim;
 use traits::inv::Inv;
 use traits::transpose::Transpose;
 use traits::rotation::Rotation;
-use traits::delta_transform::DeltaTransform;
+use traits::delta_transform::{DeltaTransform, DeltaTransformVector};
 use dim1::vec1::Vec1;
 use dim2::mat2::Mat2;
 use dim3::mat3::Mat3;
@@ -141,6 +141,12 @@ impl<M: Copy> DeltaTransform<M> for Rotmat<M>
   { self.submat }
 }
 
+impl<M: RMul<V> + Copy, V: Copy> DeltaTransformVector<V> for Rotmat<M>
+{
+  fn delta_transform_vector(&self, v: &V) -> V
+  { self.submat.rmul(v) }
+}
+
 impl<M: Copy + Transpose> Inv for Rotmat<M>
 {
   fn invert(&mut self)
diff --git a/src/adaptors/transform.rs b/src/adaptors/transform.rs
index b0811522..201e48bd 100644
--- a/src/adaptors/transform.rs
+++ b/src/adaptors/transform.rs
@@ -6,7 +6,7 @@ use traits::inv::Inv;
 use traits::rotation::Rotation;
 use traits::translation::Translation;
 use traits::transpose::Transpose;
-use traits::delta_transform::DeltaTransform;
+use traits::delta_transform::{DeltaTransform, DeltaTransformVector};
 use traits::workarounds::rlmul::{RMul, LMul};
 
 #[deriving(Eq, ToStr)]
@@ -51,16 +51,16 @@ Mul<Transform<M, V>, Transform<M, V>> for Transform<M, V>
   }
 }
 
-impl<M: RMul<V>, V> RMul<V> for Transform<M, V>
+impl<M: RMul<V>, V: Add<V, V>> RMul<V> for Transform<M, V>
 {
   fn rmul(&self, other: &V) -> V
-  { self.submat.rmul(other) }
+  { self.submat.rmul(other) + self.subtrans }
 }
 
-impl<M: LMul<V>, V> LMul<V> for Transform<M, V>
+impl<M: LMul<V>, V: Add<V, V>> LMul<V> for Transform<M, V>
 {
   fn lmul(&self, other: &V) -> V
-  { self.submat.lmul(other) }
+  { self.submat.lmul(other) + self.subtrans }
 }
 
 impl<M: Copy, V: Copy + Translation<V>> Translation<V> for Transform<M, V>
@@ -104,6 +104,12 @@ impl<M: Copy, V> DeltaTransform<M> for Transform<M, V>
   { self.submat }
 }
 
+impl<M: RMul<V> + Copy, V> DeltaTransformVector<V> for Transform<M, V>
+{
+  fn delta_transform_vector(&self, v: &V) -> V
+  { self.submat.rmul(v) }
+}
+
 impl<M:Copy + Transpose + Inv + RMul<V>, V:Copy + Neg<V>>
 Inv for Transform<M, V>
 {
diff --git a/src/traits/delta_transform.rs b/src/traits/delta_transform.rs
index 73f16c33..5db90891 100644
--- a/src/traits/delta_transform.rs
+++ b/src/traits/delta_transform.rs
@@ -7,6 +7,13 @@ pub trait DeltaTransform<DT>
 {
   /// Extracts the delta transformation associated with this transformation.
   fn delta_transform(&self) -> DT;
-  // FIXME: add functions to apply the delta-transform to a vector without
-  // explicit computation of the transform (does this avoid some matrix copy?)
+}
+
+/**
+ * Trait of delta-transformations on vectors.
+ */
+pub trait DeltaTransformVector<V>
+{
+  /// Applies a delta-transform to a vector.
+  fn delta_transform_vector(&self, &V) -> V;
 }