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Multipling differences in excel and mathcad

YA_10963798
11-Garnet

Multipling differences in excel and mathcad

I used the same inputs in mathcad and excel considering the units , however I get different results in mathcad for Mi and f2 . Do you have any clue ? 

YA_10963798_0-1717093188330.png

YA_10963798_1-1717093228710.png

 

 

7 REPLIES 7

Without the Excel AND the Prime sheet nothing substantial could be said about the two pictures you posted.

Prime can deal with units, Excel can't. So unless you used a wrong formula in Prime I would rather trust Prime's results.

I did attached them 

wait I will do it again 

Sorry, too complicated for me! I get lost with all those elaborated variable names and nested calculations. And an Excel sheet is a horror either way when it comes to understanding the calculations it contains.
Would take me much too much time to dig into all those calcs - especially since I'm not a specialist in the field this sheet is all about.

 

Maybe someone else can help.

Yeah you are totally right . 

If you just tell me in general why I would get different results in excel and mathcad , I will figure it out myself

 

in mathcad sheet the calculation of Mi is on page 9 

YA_10963798_1-1717095700727.png

 

in excel the function is 

YA_10963798_0-1717095680863.png

all inputs are  the same in both of sheets , still getting different results

 

 

As explained below I guess that the problem is the missing vectorization of expressions which use vectors.

You find it in on the Math ribbon in the "Operators" menu or you may use the appropriate keyboard shortcut (which depends on the language of your keyboard).

Werner_E_0-1717096541008.png

 

One thing which I noticed when I took a look into the Prime sheet.

Your calculation of Mi involves the multiplication of three vectors - alpha.t, q.blabla and z.

The mutliplication of the first two vectors is done as vector multiplication - that is scalar multiplication and the result is a scalar. Guess this is not what you intended. If you want the elements of the vectors to be multiplied one by one and a vector as result. you must apply vectorization!

Werner_E_0-1717095812261.png

Here is a simple example showing the difference:

Werner_E_1-1717095945048.png

 

Chances are that other calculations in your sheet may need vectorization as well.

 

Hmm
Yes this could be the reason
I will try that
 
Yusra Alsabahi
Project Manager
Civil Seven
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