# helper function to calculate grad B

helper function to calculate grad B

getBmod.m — Objective-C source code, 208 bytes

## File contents

function B_mod = getBmod(x,y,z) global B0; global Re; fac1 = -B0*Re^3/(x^2 + y^2 + z^2)^2.5; Bx = 3*x*z*fac1; By = 3*y*z*fac1; Bz = (2*z^2 -x^2- y^2)*fac1; B_mod = sqrt(Bx*Bx + By*By + Bz*Bz); endfunction