rotate() does not need to create a matrix. update test. remove superflous function in last commit.

2 files changed, 11 insertions, 11 deletions

diff --git a/chroma/cuda/rotate.h b/chroma/cuda/rotate.h
index 15f8037..f93abcc 100644
--- a/chroma/cuda/rotate.h
+++ b/chroma/cuda/rotate.h
@@ -21,6 +21,17 @@ make_rotation_matrix(float phi, const float3 &n)
 __device__ float3
 rotate(const float3 &a, float phi, const float3 &n)
 {
+    float cos_phi = cosf(phi);
+    float sin_phi = sinf(phi);
+
+    return a*cos_phi + n*dot(a,n)*(1.0f-cos_phi) + cross(a,n)*sin_phi;
+}
+
+/* rotate points counterclockwise, when looking towards +infinity,
+   through an angle `phi` about the axis `n`. */
+__device__ float3
+rotate_with_matrix(const float3 &a, float phi, const float3 &n)
+{
     return make_rotation_matrix(phi,n)*a;
 }
 
diff --git a/chroma/cuda/transform.cu b/chroma/cuda/transform.cu
index 1c5a6cb..1f4405e 100644
--- a/chroma/cuda/transform.cu
+++ b/chroma/cuda/transform.cu
@@ -31,17 +31,6 @@ rotate(int nthreads, float3 *a, float phi, float3 axis)
     a[id] = rotate(a[id], phi, axis);
 }
 
-__global__ void
-rotate_(int nthreads, float3 *a, float phi, float3 axis)
-{
-    int id = blockIdx.x*blockDim.x + threadIdx.x;
-
-    if (id >= nthreads)
-	return;
-
-    a[id] = rotate(a[id], phi, axis);
-}
-
 /* Rotate the points `a` through an angle `phi` counter-clockwise
    (when looking towards +infinity along `axis`) about the axis defined
    by the point `point` and the vector `axis` . */