Zugg Software :: View topic - [1.09] Incorrectly displayed calculations using exponentials

Wizard Joined: 03 Mar 2001 Posts: 1127 Location: London

#say %eval((1.0)/2000)
0.0005

#say %eval((1.0)/20000)
-5

Seems to be forgetting to format the number correctly when it's small

And if you then use the number
#say (%eval(((1.0)/20000))*100)

It's returning -500 (rather than 0.005)

Posted: Wed Oct 11, 2006 2:25 am

CMUD wasn't handling the exponential notation properly. Actually, doing

#say (1.0/20000)

was working fine. And remember that you don't need %eval if you put () around expressions. Adding %eval just adds another evaluation step that isn't necessary and slows down your scripts.

In this case, the above result was "5E-5". So, when this string was passed to %eval, it was trying to subtract 5 from the string 5E which is undefined.

But I've fixed 1.10 so that the parser properly handles exponential notation, so when %eval sees 5E-5 it recognizes it as a floating point value instead of a subtraction operation.

Also, your last example is incorrect...you've got all sorts of extra evaluations going on. First you have the (1.0)/20000 evaluation, then the %eval of that, then that result*100. It would be much simpler to just use

#say ((1.0/20000)*100)

which also works fine in v1.10.

Wizard Joined: 03 Mar 2001 Posts: 1127 Location: London

I think I probably tried to use an %eval at first when I did 1/20000, and it came out as 0. Then when I changed to 1.0 to force the float then I didn't think to remove the eval. The 2nd example was just showing that the -5 was being used in the next part of the calculation. Anyways though, good that it's fixed, and I'll lay off the extra %eval's in future ;)