To improve Cache Hit Ratio for larger resolutions
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

Instead of calculating residual for the next iteration, we calculate residual
iteration. This is an acceptable deviation, and a significant optimization.
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

Improves Cache Hit Ratio
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

Copying of matrix uhelp to u each time is avoided, by swapping pointers.
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

Exchanged the nested loops in relax_jacobi and residual_jacobi to ensure
linear memory access.
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

This reverts commit 639009e6.

Exchanged the nested loops in relax_jacobi and residual_jacobi to ensure
linear memory access.
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

Vanilla Code
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>