| |
| c--------------------------------------------------------------------- |
| c--------------------------------------------------------------------- |
| subroutine l2norm ( ldx, ldy, ldz, |
| > nx0, ny0, nz0, |
| > ist, iend, |
| > jst, jend, |
| > v, sum ) |
| c--------------------------------------------------------------------- |
| c--------------------------------------------------------------------- |
| |
| c--------------------------------------------------------------------- |
| c to compute the l2-norm of vector v. |
| c--------------------------------------------------------------------- |
| |
| implicit none |
| |
| |
| c--------------------------------------------------------------------- |
| c input parameters |
| c--------------------------------------------------------------------- |
| integer ldx, ldy, ldz |
| integer nx0, ny0, nz0 |
| integer ist, iend |
| integer jst, jend |
| c--------------------------------------------------------------------- |
| c To improve cache performance, second two dimensions padded by 1 |
| c for even number sizes only. Only needed in v. |
| c--------------------------------------------------------------------- |
| double precision v(5,ldx/2*2+1,ldy/2*2+1,*), sum(5) |
| |
| c--------------------------------------------------------------------- |
| c local variables |
| c--------------------------------------------------------------------- |
| integer i, j, k, m |
| |
| |
| do m = 1, 5 |
| sum(m) = 0.0d+00 |
| end do |
| |
| do k = 2, nz0-1 |
| do j = jst, jend |
| do i = ist, iend |
| do m = 1, 5 |
| sum(m) = sum(m) + v(m,i,j,k) * v(m,i,j,k) |
| end do |
| end do |
| end do |
| end do |
| |
| do m = 1, 5 |
| sum(m) = sqrt ( sum(m) / ( (nx0-2)*(ny0-2)*(nz0-2) ) ) |
| end do |
| |
| return |
| end |
