[JASS] GetRandomReal

[kevs926]

GetRandomReal(1.,100.) == 1.
GetRandomReal(1.,100.) == 1
GetRandomReal(1.,100.) <= 1.01
what is the chance of these happening?

 

[Chaosy]

Hard to say.. in GUI reals can only have 2 decimals so it's somewhat easy to calculate. Reals in jass can be pretty long though 8 decimals or something.

However I doubt GetRandomReal() uses 8 decimals when getting a random real..

x

Spoiler

assuming it's 2 decimals

GetRandomReal(1.,100.) == 1.
GetRandomReal(1.,100.) == 1
GetRandomReal(1.,100.) <= 1.01

0,01%
0.01%
0.011%

because 1. and 1 is the same thing right? or is 1. = 1.x?

 

[Lender]

If you want chanches then use GetRandomInt instead or tell us what you want to do with the random real.

if GetRandomReal uses 2 decimals then random==1 's chance is around 1/10000
random <= 1 is around 100/10000 = 1/100

 

[kevs926]

but does GetRandomReal(1,100) generetes 0.00 to 0.99?

 

[Zwiebelchen]

You should either truncate reals or use < and > to define a result range.

I don't know what the precision on GetRandomReal is, so depending on that, a perfect equal might happen between 0.01% (for 2 decimals after comma) and 0.00000001% (for 8 decimals after comma).

but does GetRandomReal(1,100) generetes 0.00 to 0.99?

It generates between 1.00 and 100.00. So no, 0.00 and 0.99 can never happen.

 

[Lender]

but does GetRandomReal(1,100) generetes 0.00 to 0.99?

for that use GetRandomReal(0.,0.99) or 0,1 whichever u want to allow 1 too

 

[WaterKnight]

You can map the results of GetRandomInt to your range. Ex: GetRandomInt(0, 100) / 100.0

 

[Zwiebelchen]

You can map the results of GetRandomInt to your range. Ex: GetRandomInt(0, 100) / 100.0

I2R(GetRandomInt(0, 100)) / 100.0 for consistency.

 

[Ezekiel12]

All the stuff about the decimals of a real is just plain wrong. Especially Chaosy, who started all this.

Wc3 uses IEEE 754 single-precision binary floating-point format, or something very similar.

There are no GUI-reals and JASS-reals, it's all the same. Whenever you deal with reals the game converts your input to the closest real that can actually be represented in the format.

@OP: The chance for your conditions to be true are extremely small.
If you want to represent some percentage chance, just use GetRandomInt.

 

[kevs926]

random <= 1 is around 100/10000 = 1/100

so this is false?

 

[kevs926]

so basically i guess the question is..whats the binary counterpart of "1" and how many binary reals are there (1,100)

 

[Zwiebelchen]

so basically i guess the question is..whats the binary counterpart of "1" and how many binary reals are there (1,100)

Do you even understand what you are trying to achieve?
If you want to code a custom droplist, there's no need to use '='. Just just use '<' or '>'.


So, for example, if you want stuff to happen at a 1% chance, just use this:
if GetRandomReal(0,100) < 1. then

 

[Ezekiel12]

so this is false?

Yes, the chance for (GetRandomReal(1.,100.) <= 1.01) to be true is much much less than 1%.

so basically i guess the question is..whats the binary counterpart of "1" and how many binary reals are there (1,100)

Do you want to make some percentage chance calculation out of my answer or what do you want actually?

If yes, as already advised, you should not do that and use GetRandomInt because we can't be sure how reals are handled exactly internally.
If you end up using something like GetRandomReal(1,1.022134211)<1.012412422 you deserve to be slapped with a trout