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02-20-2019
08:06 AM

02-20-2019
08:06 AM

Vector Solve Block Simple Equation

Hi,

I am really new to Mathcad.

I have a problem to find a "d" variable in constraint with L as the dependent factor. The problem is, I want to get "d" with range variables of L from 0 to 1000 mm. So I get range value of "d" based on the L inputs.

Could we do this by that way with solve block? Appreciate your guy's help

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9 REPLIES 9

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02-20-2019
08:29 AM

02-20-2019
08:29 AM

Re: Vector Solve Block Simple Equation

Yes, you could. But I think it's much simpler if you first solve, like this:

That is, you define a function d, where the definition uses a symbolic solve. That 'll get you best accuracy, and speed.

In your case, R=0.85.

Now if you make M a function of z, and z a function of L, D and t, you can call:

d(S.F,S.flow,t,M(z(L,D,t)),0.85)=...

And you can plot d(...) versus L.

Success!

Luc

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02-20-2019
08:40 AM

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02-20-2019
08:50 AM

02-20-2019
08:50 AM

Re: Vector Solve Block Simple Equation

Hi,

Along the same line of thinking paramatise the solve block in terms of L

Cheers

Terry

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02-20-2019
08:58 AM

02-20-2019
08:58 AM

Re: Vector Solve Block Simple Equation

In other words, simply like this:

Success!

Luc

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02-20-2019
09:23 AM

02-20-2019
09:23 AM

Re: Vector Solve Block Simple Equation

I did mine the way I did as I believe it's faster. As I understand things, once mathcad starts iterating it will call M(L), and hence z(L), for each iteration. Not a big deal here, but it can slow things down in big programs. Also the solver isn't terribly robust imho and gets confused with 'constants' inside of a solve block. I've found the 'program' internal to the solve block to be very effective. But that's probably more than our poster needs to know at this point.

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02-20-2019
09:27 AM

02-20-2019
09:27 AM

Re: Vector Solve Block Simple Equation

Thanks for the hints DJF

Terry

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02-20-2019
09:32 AM

02-20-2019
09:32 AM

Re: Vector Solve Block Simple Equation

You made my day simpler. Really appreciate it

Thanks,

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02-20-2019
09:34 AM

02-20-2019
09:34 AM

Re: Vector Solve Block Simple Equation

Thanks DJF, it is also another way of thinking that solve my problem as well.

Cheers!!

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02-20-2019
02:34 PM

02-20-2019
02:34 PM

Re: Vector Solve Block Simple Equation

Here is a way which follows closely your approach and still avoids multiple calculation of M(L) during iterations:

But I agree with Luc that in case of your rather simple equation it would be better to solve it symbolically and go for the most direct approach:

Worksheet in Format Prime5 attached

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