algebraic loop simulink error؟؟

when using Ipold= Ip in this embedded function code

function [e,Pm,Ip] = new(In,Vn) persistent Ipold ; if isempty(Ipold) Ipold=2; %initialized only once in the beginning end K1=2; K2=-.195; Pn= Vn*In Pm=100*In e= Pn-Pm if Pn>Pm Ip = Ipold+K1 *e else Ip = Ipold+K2 *e end Ipold=Ip

error message appeared "Trouble solving algebraic loop containing 'chee_pv/pv6/Algebraic Constraint/Initial Guess' at time 0. Stopping simulation. There may be a singularity in the solution. If the model is correct, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)"

[mado]

any help