Detecting a NAN
Blitz3D Forums/Blitz3D Programming/Detecting a NAN
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| Hey peeps, how can i detect if a Float has buggered up? when an object resets, it gets moved through another object knocking it flying- which causes it it to move so fast that everything turns NAN. What i want to do, is detect the NAN, and then reset everything, or at least, give a decent runtime error. |
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| prevent divisions through "0" or nearly 0. I guess you have a FPS bound movement and do not have an FPS precalculation before players can do anything to prevent the 0 division problem. a possibility is: function divide#( a#, b# ) epsilon# = 0.0001 if b > epsilon return a / b else return a / epsilon endif end function haven't had NAN cases so far beside the 0 division |
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| heh, im not doing the division though, ODE is. and its just rotation, so the fix is simply to set it to 0 when it happens (well, i hope...) |
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| =null? |
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| If a>a then runtimeerror "NANANANANA" |
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And to catch infinite values at the same time:If (f + 1) = f Then RuntimeError("Got a NaN or an Inf") |
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| Cheers, Perfect :D |
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| There is another way to detect a NaN, wait til xmas and see who gets you the socks! That's your Nan right there! :) |
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| :p actually, i found If var=Nan actually worked- now i just have a wheel go missing instead of a grey screen :/ |
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| Nan is a keyword/constant? |
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| No. Cygnus. I believe that just creates a new variable called nan, which would therefore also detect var=0.0. If you want to go down that route though you could define Global zero#=0.0, Infinity#=1.0/zero, Nan#=zero/zero. |
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| By Jove DJW, that works! cool :) |
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| If you'd like them to be constants, you can do this: Const Infinity = (999.0)^(99999.0) Const NaN = (-1.0)^(0.5) |
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| Odd, because it actually is only triggering the code when it equals "NaN"... my cars are getting cleared and reloaded when a NAN is detected, but now, every 5 or so clearances causes another error i gota sort. if var=NaN detects 0 then the cars would be reset whenever they arent moving.. which doesnt happen (im checking a variable as well as displaying its contents on screen) Interesting stuff this..... |
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| NaN isn't a reserved keyword! It's just a variable, which is never setup and thus has the value 0. If var = NaN totally doesn't work, unless you use something like my Const Nan = (-1.0)^(0.5) above. What also works is; If var = "NaN" Since var is automatically cast to a string, and String( <not a number> ) = "NaN". |
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| As well as 'if var="Infinity"' and 'if var="-Infinity"' BTW |
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| Odd, as always, you guys are right- it was working but it did cause glitches. fixed :/ |
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