Dear Mr.Bhargava ,
What you say is correct,that is circular reference error ,
I have attached PDF file togathe,it has some sequence of IF function ,used for animation a line in reciprocating motion , this formula i download form solid work tips ,but i try it ,it shows some error ,
The new equation editor broke some old functionality, some of which was unintended/undocumented. Not much we can do about that.
this must be a pretty old SolidWorks Tip since we do not allow identical active left hand sides in equation for some time. I can remember that some releases ago it was possible to specify an equation like D1@Sketch1 = 5 and in the next line you could specify that D1@Sketch1 = 3. I just double checked in 2011 and there it is also not possible to specify two equations for one dimension. So nothing that is specific to 2012 and the changes we made with 2012.
As Rhagvendra already pointed out there is a setting that turns off the circular reference warnings. Giving a warning for circular references is in general a good thing as usually users don't want to have an eternally changing part that changes the shape with every rebuild. However in some particular cases (like this one for animation purpose) it makes sense to allow them and in 2012 we have not blocked the creation of circular references.
I looked at the equations mentioned above and tried to put them into one nested if statement (by the way, if you want to use nested if statements you might want to build them with the old iif syntax as it seems that there is something broken with the new syntax):
The sketch entities change with every rebuild (become bigger and then smaller and bigger...). Perhaps you want to give it a try.
Product Definition Team