I have problem about aA wave net pid controllers for AQM routers

clc; close all;

MP=input('Learning rate of proportional='); MI=input('Learning rate of integral='); MD=input('Learning rate of derivative='); Pr=input('proportional gain='); In=input('Integral gain='); Dr=input('Derivative gain='); upper=input('upper interval='); lower=input('lower interval='); wl=input('number of wavelones='); xx=input('dilation='); c=input('IIR feed-forward coefficient='); d=input('IIR feed-back coefficient='); N=input('number of FF delays='); M=input('number of FB delays='); v=input('co-input='); accuracy=input('accuracy='); ma=input('Learning rate of dilation='); mb=input('Learning rate of translation='); mw=input('Learning rate of weight='); mc=input('Learning rate of FF coefficient='); md=input('Learning rate of FB coefficient=');

z=1; for i=0:.11:200 if i>0 & i<=50 r(z)=300; elseif i>50 & i<=100 r(z)=200; elseif i>100 & i<=150 r(z)=500; elseif i>150 & i<=200 r(z)=200; end z=z+1; end

////////// error after run the programe////////

Conversion to function_handle from double is not possible.

Error in hindawavenetpid (line 28) r(z)=300;