Numerical Grid

RNS uses a uniform 2-D grid in the variables s=r/(r+r_e) and $\mu= \cos \theta$. The center is at s=0, the equator at s=0.5 and infinity at s=1. The equatorial plane is at $\theta=\pi/2$ while the pole is at $\theta=0$. If one uses SDIV points in the s-direction and MDIV points in the $\mu$-direction, then the grid points are obtained by the formulas

$$s[i]=0.9999 \Bigl( {1-i \over SDIV-1} \Bigr),$$ (4)

$$\mu[j]=\Bigl( {1-j \over MDIV-1} \Bigr).$$ (5)

The default grid size is $MDIV \times SDIV=65 \times 129$. You can change this by editing the Makefile. If you specify too large a grid size and get a memory segmentation fault, you can fix this by issuing the command

limit stacksize unlimited

in a UNIX environment.