if statement in ade xl

Dear Holz,

Holz said:

I know its possible to write something like out= if( (a==b) then 1 else 0), so I write like:

if (  (a==b) then ( if ( (c==d) then current else -current) )   else 0)

But I get error:

"input.scs" 9: Parameter `I_ainv': Cannot run the simulation because an unknown parameter `if' has been specified in expression `if'

Does anyone know why it happens?

A couple of comments if I may...not sure they will help...but came to mind

1. Did you try to remove the space character between the "if" and left parenthesis "("? In SKILL or in ocean/VIvA, the syntax of an if statement requires there be no white character between a function - such as the condition if expression - and the following left parenthesis. Your error message suggests ADEX-L is not recognizing the "if" as the SKILL conditional expression and treating it as a global variable. Hence, you might try the following (note missing spaces after "if"):

if(  (a==b) then ( if( (c==d) then current else -current) )   else 0)

2. As I am sure you know, ADE-XL is no longer actively supported by Cadence. I might suggest you consider the relatively painless transition to the more modern Assembler/Explorer views. Assembler behavior is very very similar with the capability to easily import any ADEX-L state(s) you may have created. It also supports a lot more functionality than ADE-XL.

3. I and not sure what version of the tool you are using, but there a way tf you have not seen them, there is a Cadecnce On-line support article entitled 

"How to set value of global variables based on the value of other global variable" at URL:

https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O0V000007MpwKUAS&pageName=ArticleContent

This might be helpful to you as it provides a SKILL based function.

4. There is also a second application note concerning the use of conditional expressions with local variables and a workaround for earlier versions of Virtuoso (IC 6.1.6)

https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000nXT2EAM&pageName=ArticleContent

I hope these help Holz!

Shawn

This is most likely to be the erroneous spaces (plus having some unnecessary parentheses may not help). In essence, ADE XL tries to evaluate global variables as SKILL expressions first (ADE Assembler does the same), and if that fails to evaluate, it assumes the expression can be handled by the simulator - and that's why it fails in the simulator (since that doesn't have such an if expression). So you can simplify it as follows:

if(a==b then if(c==d then current else -current) else 0)

In fact, you can take advantage of the fact that the SKILL if function can omit the then/else keywords if there is only a single statement for the then and else parts:

if(a==b if(c==d current -current) 0)

although you might find that less readable.

Regards,

Andrew

This is most likely to be the erroneous spaces (plus having some unnecessary parentheses may not help). In essence, ADE XL tries to evaluate global variables as SKILL expressions first (ADE Assembler does the same), and if that fails to evaluate, it assumes the expression can be handled by the simulator - and that's why it fails in the simulator (since that doesn't have such an if expression). So you can simplify it as follows:

if(a==b then if(c==d then current else -current) else 0)

In fact, you can take advantage of the fact that the SKILL if function can omit the then/else keywords if there is only a single statement for the then and else parts:

if(a==b if(c==d current -current) 0)

although you might find that less readable.

Regards,

Andrew

Hi Andrew,

I have solved this problem use skill, thanks