# [Numpy-discussion] Can I further Numpy-ize this code?

Rob europax at home.com
Thu Sep 27 18:07:03 CDT 2001

```I've been working on this for so long I may be missing the obvious.
Here is a snippet of code that I would like to at least get rid of one
more indexing operation.  The problem is the presence of the one
dimensional array constants which are functions of x,y, or z depending
on their location:  (you may recognize this as some FDTD code)  Any
ideas?

Thanks,  Rob.

####################################/
# Update the interior of the mesh:
#    all vector H vector components
#

##   for az in range(0,nz):
for ay in range(0,ny):
for ax in range(0,nx):

dstore[ax,ay,0:nz]=Bx[ax,ay,0:nz]

Bx[ax,ay,0:nz] =  Bx[ax,ay,0:nz] * C1[0:nz] + ( (
(Ey[ax,ay,1:(nz+1)]-Ey[ax,ay,0:nz] ) / dz -
(Ez[ax,ay+1,0:nz]-Ez[ax,ay,0:nz]) / dy ) * C2[0:nz] )

Hx[ax,ay,0:nz]=  Hx[ax,ay,0:nz] * C3[ay]  + ( (
Bx[ax,ay,0:nz] * C5[ax]  - dstore[ax,ay,0:nz] * C6[ax] ) *
C4h[ay] )

dstore[ax,ay,0:nz]=By[ax,ay,0:nz]

By[ax,ay,0:nz] =  By[ax,ay,0:nz] * C1[ax]  +  ( (
(Ez[ax+1,ay,0:nz]-Ez[ax,ay,0:nz]) / dx -
(Ex[ax,ay,1:(nz+1)]-Ex[ax,ay,0:nz]) / dz ) * C2[ax] )

Hy[ax,ay,0:nz]=  Hy[ax,ay,0:nz] * C3[0:nz] +  ( (
By[ax,ay,0:nz] * C5[ay] - dstore[ax,ay,0:nz] * C6[ay] ) *
C4h[0:nz] )

dstore[ax,ay,0:nz]=Bz[ax,ay,0:nz]

Bz[ax,ay,0:nz] =  Bz[ax,ay,0:nz] * C1[ay] +  ( (
(Ex[ax,ay+1,0:nz]-Ex[ax,ay,0:nz] ) / dy -
(Ey[ax+1,ay,0:nz]-Ey[ax,ay,0:nz] ) / dx ) * C2[ay] )

Hz[ax,ay,0:nz]=  Hz[ax,ay,0:nz] * C3[ax] +  ( (
Bz[ax,ay,0:nz] * C5[0:nz]  - dstore[ax,ay,0:nz] * C6[0:nz]
) * C4h[ax] )

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```

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