Power errors

GAMS
1

Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

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2

On Thursday, July 19, 2012 8:33:38 AM UTC-7, Adei wrote:



Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

–
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3

hello friend.
I think that you should use double star instead of power means **.

— On Thu, 7/19/12, ali wrote:


From: ali
Subject: Re: Power errors
To: gamsworld@googlegroups.com
Date: Thursday, July 19, 2012, 5:59 PM



On Thursday, July 19, 2012 8:33:38 AM UTC-7, Adei wrote:



Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

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4

I assume the ‘e’ in your expression is non-integer. In gams, the POWER function requires the exponent to be an integer. As suggested by Samieh, using ** instead of power can work for you. But also in the later case, the root need to be positive real number (in your case, P).

HTH,
Destin

On Tue, Jul 24, 2012 at 9:41 AM, Samieh Amanaty wrote:

hello friend.
I think that you should use double star instead of power means **.

— On Thu, 7/19/12, ali wrote:


From: ali
Subject: Re: Power errors
To: gamsworld@googlegroups.com
Date: Thursday, July 19, 2012, 5:59 PM




On Thursday, July 19, 2012 8:33:38 AM UTC-7, Adei wrote:



Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

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5

You may learn more about the differences in the following link.
http://support.gams.com/doku.php?id=gams:difference_between_the_-operator_and_the_power_function

Bests,
Destin

On Tue, Jul 24, 2012 at 3:39 PM, Destin Zed wrote:

I assume the ‘e’ in your expression is non-integer. In gams, the POWER function requires the exponent to be an integer. As suggested by Samieh, using ** instead of power can work for you. But also in the later case, the root need to be positive real number (in your case, P).

HTH,
Destin


On Tue, Jul 24, 2012 at 9:41 AM, Samieh Amanaty wrote:

hello friend.
I think that you should use double star instead of power means **.

— On Thu, 7/19/12, ali wrote:


From: ali
Subject: Re: Power errors
To: gamsworld@googlegroups.com
Date: Thursday, July 19, 2012, 5:59 PM




On Thursday, July 19, 2012 8:33:38 AM UTC-7, Adei wrote:



Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

–
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6

Hey guys,
thanks for your suggestions.

I wrote Pe , where P is a positive variable and e is a scalar equals -3. and then I got the following error:
rPower: FUNC DOMAIN: xy, x=0,y wrote:

hello friend.
I think that you should use double star instead of power means **.

— On Thu, 7/19/12, ali wrote:


From: ali
Subject: Re: Power errors
To: gams...@googlegroups.com
Date: Thursday, July 19, 2012, 5:59 PM




On Thursday, July 19, 2012 8:33:38 AM UTC-7, Adei wrote:



Hello there,

I am building a mixed integer non linear programming model , in my objective function I have this term PalphaPower( P , (-e))

I’m keep getting the following errors ::

**** Exec Error at line 48: power: FUNC SINGULAR: pow(x,i), |x| tiny, i < 0
**** Exec Error at line 48: overflow in * operation (mulop)

would you please explain what these errors mean ?
Any suggestions to solve this issue ??!!


Thanks in advance,
Adei

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7

Adei, 2012-09-06 15:33:51
Subject：Re: Power errors

I wrote Pe , where P is a positive variable and e is a scalar equals -3.
and then I got the following error:
rPower: FUNC DOMAIN: xy, x=0,y > Then I tried power(P,e) and then I got the following error:

                     FUNC SINGULAR: pow(x,i), |x| tiny, i < 0

the error message is clear,
pow(x,-3) means 1/x^3, it would be a huge number when x is tiny.
you may want to check why x has such a tiny value in your system, or init it with a bigger value.

HTH,

Yan

\

8

hi,
‘y’ is a set and you can not use it as number! I think, you want to write some thing like following:

sets
y index set of years within the planning horizon /1*5/;

parameters
DR nominal discount rate /0.02/
DF(y) discount factor for year y
year(y) /1 = 1, 2 = 2, 3 = 3, 4 = 4, 5 = 5/;


DF(y)=1/((1+DR)**year(y));

display DF


I hope, it be helpful.
From: “alyasivrikaya@gmail.com”
To: gamsworld@googlegroups.com
Sent: Thursday, February 28, 2013 7:01 PM
Subject: power errors

Hi,
I’m just learning gams. This is a part of my code.

sets
y index set of years within the planning horizon /1*10/;

parameters
DR nominal discount rate /0.02/
DF(y) discount factor for year y;
DF(y)=1/((1+DR)**y);

I’m getting the following errors:

Error 148: dimension different
Error 128: exponent of power not a real number

how can i solve this issue?

Thanks.

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9

Hello,

Actually,It’s very simple.
Using the function ord(set),all you need is
change DF(y)=1/((1+DR)**y);
into DF(y)=1/((1+DR)**ord(y));

By the way,the GAMS user’s guide is really helpful!

Hope it helps!
Regards!

Philms

On Thursday, February 28, 2013 11:31:15 PM UTC+8, alyasi...@gmail.com wrote:

Hi,
I’m just learning gams. This is a part of my code.

sets
y index set of years within the planning horizon /1*10/;

parameters
DR nominal discount rate /0.02/
DF(y) discount factor for year y;
DF(y)=1/((1+DR)**y);

I’m getting the following errors:

Error 148: dimension different
Error 128: exponent of power not a real number

how can i solve this issue?

Thanks.

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