nc is the [b]n[/b]umber of [b]c[/b]oils for the calculation.
np is the [b]n[/b]umber of [b]p[/b]oints for each coil for the calculation.
[b]N[/b]umber of [b]f[/b]iled lines are defined by nf (default=24). You might be able to change it to smaller value.
However, you can not change it to larger number without redefine all those array for (xf,yf,zf,...).
You need to redefine the default for nf if you need more number of lines and do not forgot to call _initialize().