Data_Valid_P( ) ??
 

How to combine this argument{ Data_Valid_P() } with below equations ??because ,i must protect Unavilable Data access in my program , it will occur a mistakable message.i want to get a correct value from below program . hlep me to solve this problem ~~

Eta = T / E * ln(Eta/I);

T , I , E is constant

kevin

load a user-defined function ,if fuction performs a calculation