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

Rob europax at home.com
Thu Sep 27 20:12:01 CDT 2001

```I fixed my code by turning the one dimensional arrays into 3 dimensional
ones.  This is much faster and totally sliced.  But there still must be
a way thats even faster.  Rob.

Rob wrote:
>
> 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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