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09-11-2020
08:50 PM

09-11-2020
08:50 PM

Please help. I am not sure why it is complaining about the units. Both numerator and denominator are in Ohms

zd1(s) ---> Ohms (numerator)

s*L1 ---> Ohms (denominator)

Solved! Go to Solution.

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09-15-2020
11:26 AM

09-15-2020
11:26 AM

Hi

Thanks for all the helps. Not use to vectorize a function yet but will do it from now on

Rdliquid

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09-11-2020
09:28 PM

09-11-2020
09:28 PM

Re: These units are not compatible

Either delete the equal sign at the end or delete the "(s)" after T

You have to decide if you want define a function T() (no "=" at the end!) or if you want to define a variable T

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09-12-2020
02:05 AM

09-12-2020
02:05 AM

Re: These units are not compatible

This is an old mistake, or rather a flaw.

Once upon a time, the developers of Mathcad created the tandem-operator ... := ... = ..., but forgot to attach it not only to variables, but also to functions. And the error messege is not correct.

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09-12-2020
02:22 PM

09-12-2020
02:22 PM

Re: These units are not compatible

HI

Thanks a lot for all your helps. I deleted the "=" at the T(s) expression and it is now working. Unfortunately I have one more question, may not related to the original question.

I defined D(s):=|T(s)| and vectorized on top of the |T(s)|, then I evaluated the D(s) expression and it seems correct.

However, when I try: MAG_T(s):=[(Re(T(s))^2+(Im(T(s))^2]^0.5 returns values around 10^-54 which is a very low number and its results do not match with D(s):=|T(s)| vectorized which returns around 0.06 or so

Do you know why?

Please see attached file

Thanks for your helps again

rdliquid

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09-12-2020
03:20 PM

09-12-2020
03:20 PM

Re: These units are not compatible

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09-12-2020
04:47 PM

09-12-2020
04:47 PM

Re: These units are not compatible

However, when I try: MAG_T(s):=[(Re(T(s))^2+(Im(T(s))^2]^0.5 returns values around 10^-54 which is a very low number and its results do not match with D(s):=|T(s)| vectorized which returns around 0.06 or so

Do you know why?

Yes, I do.

Valery already showed the solution - you have to vectorize the expression.

The reason is the difference between T(s) and T(s) vectorized

Why the difference? Because of functions like z.d1(s). They include z1(s)*s. z1(s) returns a vector and s is a vector. So without ~~multiplication~~ vectorization you get the vector product. This is not what you want - you want to feed every single element of s in your function and collect the scalar results in a vector. And this is exactly what vectorization is good for.

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09-15-2020
11:26 AM

09-15-2020
11:26 AM

Hi

Thanks for all the helps. Not use to vectorize a function yet but will do it from now on

Rdliquid