Undefined function 'chi' for input arguments of type 'double'.

I am calculating zeroth order Bessel root function using function 'chi'. This yielded me the roots successfully for the range I had asked for. Now today when I m running the same code, 'Undefined function 'chi' for input arguments of type 'double' has been displayed. one day this function is acceptable and the next day it is not. I m unable to understand this.Anybody please help.

[madhan ravi]

Upload the code.

Answer 1

[Walter Roberson]

chi is not a Mathworks function, and does not appear to be part of any File Exchange contribution either.