James Willis
--- a/src/kernel_hydro.h
+++ b/src/kernel_hydro.h
+* Return 0 if $u > \\gamma = H/h$
+*
+* @param u The ratio of the distance to the smoothing length $u = x/h$.
+* @param W (return) The value of the kernel function $W(x,h)$.
+* @param dW_dx (return) The norm of the gradient of $|\\nabla W(x,h)|$.
+*/
+
+__attribute__((always_inline))
+   INLINE static void kernel_deval_vec(vector *u, vector *w, vector *dw_dx) {
+
+ vector ind, c[kernel_degree + 1], x;
+ int j, k;
+
+ /* Go to the range [0,1[ from [0,H[ */
+ x.v = u->v * vec_set1((float)kernel_igamma);
+
--- a/src/kernel_hydro.h
+++ b/src/kernel_hydro.h
+     c[j].f[k] = kernel_coeffs[ind.i[k] * (kernel_degree + 1) + j];
+
+ /* Init the iteration for Horner's scheme. */
+ w->v = (c[0].v * x.v) + c[1].v;
+ dw_dx->v = c[0].v;
+
+ /* And we're off! */
+ for (int k = 2; k <= kernel_degree; k++) {
+   dw_dx->v = (dw_dx->v * x.v) + w->v;
+   w->v = (x.v * w->v) + c[k].v;
+ }
+
+ /* Return everything */
+ w->v = w->v * vec_set1((float)kernel_constant) * vec_set1((float)kernel_igamma3);
+ dw_dx->v = dw_dx->v * vec_set1((float)kernel_constant) * vec_set1((float)kernel_igamma4);
+
--- a/tests/testKernel.c
+++ b/tests/testKernel.c
 *
 ******************************************************************************/

+#define NO__AVX__