Error "??? Attempted to access p(15); index must be a positive integer or logical."

I am getting error . Please help me its urgent "Warning: FOR loop index is too large. Truncating to 2147483647. > In NR at 7 ??? Attempted to access p(15); index must be a positive integer or logical.

Error in ==> NR at 11 p(q+1)=yi(k+1);"

When i debug this program

%Newton Rapson Method Iteration
clc
s=0:1:100;
yi=1:0.1:300;
for xi=0:0.01:5

    for k=1:1:inf
        yi(k+1)=yi(k)-(fvalue(xi,yi(k))/dvalue(xi,yi(k)));
        e=((yi(k+1)-yi(k))/yi(k+1))*100;
        q=xi*100;
        p(q+1)=yi(k+1);
        if (e<5)&(e>-5)

            p
            break
        end
    end

end

Answer 1

[Matt Fig]

In general, q will not be an integer. See the many discussions on floating point arithmetic here and on CSSM.

Also, perhaps a WHILE loop would be better? This will rid you of that warning message.

    k = 1;
    while 1
    % Your code here, no FOR loop needed.  Use loop counter k.
    k = k + 1;
    end

Answer 2

[Walter Roberson]

k = 0;
while true
  k = k + 1;
  ....
end

"for" loops should not be used for infinite loops.