add optimization 5 that unrolls the 1D wavelet kernel and avoids regi…

…ster spills.

init_y.h

@@ -0,0 +1,21 @@
+// Write bx * by * bz blocks each of dimension nx * ny * nz
+void init_y(float*& out, int nx, int ny, int nz, int bx, int by, int bz) {
+
+        size_t block = nx * ny * nz;
+        out = (float*)malloc(sizeof(float) * block * bx * by * bz);
+
+        // Number of blocks
+        for (int jz = 0; jz < bz; ++jz)
+        for (int jy = 0; jy < by; ++jy)
+        for (int jx = 0; jx < bx; ++jx) {
+                // Block dimension
+                for (int iz = 0; iz < nz; ++iz)
+                for (int iy = 0; iy < ny; ++iy)
+                for (int ix = 0; ix < nx; ++ix) {
+                        size_t pos_block =  ix + nx * (iy + ny * iz);
+                        size_t pos = pos_block + block * (jx + bx * (jy + by * jz));
+                        out[pos] = iy;
+                }
+        }
+}
+