question about rank error in function

Academy Support
1

https://learninghub.kx.com/forums/topic/question-about-rank-error-in-function

I tried to abstract the Newton-Raphson method in this function, where the user can input a value of c, a first guess x0, and p, the value at which x is raised. However i get a rank error when applying it to for example:
fbis [2; 1; 3].

Can someone explain why?

fbis : {[c_, x0, p_] {[xn ; c; p] xn - ((xn xexp p)-c)%(p * xn xexp p-1)}[; c_; p_]\[x0]}

Thank you!

2

, rather than ; separating the arguments of fbis. Otherwise runs fine:

q)fbis:{[c_;x0;p_]{[xn ;c;p] xn-((xn xexp p)-c)%(p*xn xexp p-1)}[;c_;p_]\[x0]}
q)fbis[2;1;3]
1
1.333333
1.263889
1.259933
1.259921
1.259921
3

thank you!
Silly mistake