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### x^y, where x<0 and y non-integer

Posted: **Wed Nov 29, 2017 3:24 pm**

by **Loreno**

this seems silly, but i cant get it done:

i want to simply calculate

x^y, but neighter the **operator nor the power() function is working, because x<0 and y is non-integer.

example:

(-0.1)^(1/5)

how can i do this in gams?

### Re: x^y, where x<0 and y non-integer

Posted: **Wed Nov 29, 2017 5:58 pm**

by **Fred**

Loreno,

What you try to do is mathematically not defined.

Fred

### Re: x^y, where x<0 and y non-integer

Posted: **Thu Nov 30, 2017 10:11 am**

by **Loreno**

oh, i guess its been to long, that i have been to math class:) the reason i thought that it works, is that google actually gave me a result.

solution: (yes mathematicly not the same, but what i logicly wanted to do anyways)

-(abs(x)**y)

### Re: x^y, where x<0 and y non-integer

Posted: **Fri Dec 01, 2017 6:50 am**

by **Fred**

Hi Loreno,

The signPower function may be what you are looking for:

https://www.gams.com/latest/docs/UG_Par ... =signpower
I hope this helps!

Best,

Fred