Refer to another output equation in ADE

You didn't say which version you're using - so I'm assuming this is ADE in IC5141 or ADE L in IC613.

You can't just refer to an output by name (support for that is added in IC614). If you make the expressions:

pin3:  pin3=(power from the 3.3V supply)
pin12:  pin12=(power from the 12V supply)
ptot:  pin3+pin12

In other words, put a varName= before each expression - it will then evaluate the expression which will include an assignment to a SKILL global variable. The expressions are evaluated top to bottom, and so you need to ensure that you don't refer to a variable before defining it.

In IC614 variables will automatically get created for each output (they won't be global though, but available within the scope of the expression evaluation).

If you're using IC61X and ADE XL, then you can use the calcVal() function. This can easily be set up by dragging an output from the ADE XL outputs pane into the calculator buffer - and it will automatically set up the calcVal expression for you.

Regards,

Andrew.

I'm using ADE GXL 6.1.3.1, so this calcVal thing should work. If I drag an expression to the calculator, then it does make a calcVal function from it, but trying to evaluate it results in an error:

 *Error* ("eval" 0 t nil ("*Error* eval: not a function" calcVal("pin3" "myproj:my_amp_tb:1")))

The same error occurs quite often by the way, also with other functions:

*Error* ("eval" 0 t nil ("*Error* eval: not a function" (average(clip(IT("/V5/MINUS") 5e-05 0.0001)) * 12)))

The "not a function" messages normally implies you have additional nested parentheses around an expression.

For example, if you do ((2+2)) then you'll get a similar message. So check for unnecessary parentheses.

Regards,

Andrew.

It works, some of the time. I currently perform a sweep of vin (input voltage) over 40 points. I then calculate:

vout_av: (vout_av = (some stuff to compute the average output voltage))
delta: (delta = (vout_av / 12))
iout: (iout = (vout_av / 48))

Now this almost works. Vout_av gives the correct value, a scalar voltage. Same for delta, it is a scalar voltage equal to vout_av / 12. However, iout doesn't work. It should be equal to a scalar voltage equal to vout_av divided by 12, but instead it gives a vector containing these values as a function of vin. And it does this for every point of the sweep! Now how can delta and iout be of different types when they have been defined almost identically?

Perhaps you can first try the latest hotfix of IC613 - it's possible this has been fixed since the IC613 "Update" release (which is what  you're using) from nearly a year ago?

If that's not successful, I would suggest contacting Cadence customer support with an example that illustrates this. I've not seen similar issues, so it's probably data-specific.

Best Regards,

Andrew.

OK, I'll go check whether there are any updates left to install. In the meantime, there's one small thing bothering me: on the "Results" tab, there's now a huge list of old variables that I've used while trying to work around this problem. Is there any way to remove old expression results from the Results tab? They are no longer on the "Outputs setup" tab, but I don't see a "delete" option anywhere on the Results tab.

They won't appear next time you run the simulation - it's just because you're seeing your "work in progress"...

Regards,

Andrew.

Actually, I've been wondering a bit about whether I'm doing it correctly at all. If it is so unobvious (and undocumented in the manual) how to make equations refer to one another, does this mean that there's a better way of constructing complex equations?

I mean, if you use the calculator, you can perform lots of calculations on your simulation data, but it's a manual process. It makes more sense to set up an equation and let Virtuoso automatically evaluate it after every simulation. It seems intuitive to me (from experience with other simulation programs) to just make a list of equations in the Outputs Setup, but if it is so complicated to make equations refer to each other, does this mean that Virtuoso's designers are expecting you to do your data processing in some other way (such as writing a script)?

This is very easy to do in ADE XL (in IC613). You can create an "OCEAN Script" measure in the ADE XL output, which will be an attached text file containing all your calculations, and then you can "output" one or more of the calculations to the outputs pane in ADE XL, keeping other variables interneal.

You can also refer to other outputs very easily - you just need to click on an output in ADE XL and drag it into the calculator input buffer, and it will generate the right expression to refer to it (using the calcVal() function).

In ADE L, in IC614 (due later this year) you will be able to simply refer to one of your other outputs by name in a calculation. ADE will take care of ordering your outputs so that it does things in the right order (and indeed you can manually reorder things by dragging the outputs up or down in the ADE L window).

If using ADE L in IC613, you could always put all your calculations in a function definition (it's SKILL after all) and then call that function from the ADE L outputs pane - you can then make your calculations as complicated as you like.

So there are lots of ways of doing this, dependending on your preferences - we try to cater for both people who like scripting, and those who just want a GUI.

Regards,

Andrew.

Thanks for the info. For not-too-complicated expressions, I prefer to just do everything in the Ouputs Setup tab. However, you said that it's necessary to define the expressions in the correct order. Is it then possible to change the order of the expressions after you've made them? Adding a new expression just adds it to the end of the list, I can't find a way to add one halfway.