Mathcad Wishlist - Units definition control

Question

Mathcad Wishlist - Units definition control

edmeister (Aeronautics)

(OP)

18 Jan 23 16:01

Don't u just hate it when Mathcad interjects into a worksheet/calculation and assigns a constant or universal units to some variable in the calculation. This thereby leads to me wasting time going thru every line and determining where the error is ..
- I would like the UNITS tab have a checkbox that allows which units I would like to maintain (& also define new declarations) pertinent to my needs. I deal with inches / feet / psi /ksi / Lbf - 90% of the time . I have no need to deal with Energy Units or Charge units etc. For example constant c (speed of light)does not apply to my needs but manages to sneak into my work when i use the value c as a counter ..

Sparweb (Aerospace) · Answer 1 · 2023-05-20 01:04:34

To address preferred units in Mathcad, I long ago prepared a template worksheet with a bunch of stuff at the top on the far right margin so that it wouldn't print into the main body of the page. Since MC reads from top down, it was active and set up my sheets to use readable units in the context of my work. I needed things like "knots" and "USGAL" to make sense. Also, I often have to shift measurement systems so I could make "degF" and "degC" function interchangeably WITH conversion when I assigned them.

As for the speed of light, I believe there still is a setting that protects built-in units. If you turn it off, then you can sabotage the meaning of any unit you like. "m" for miles and "c" for counter and "K" for kilograms as you please.

IFRs (Petroleum) · Answer 2 · 2023-05-20 01:46:04

In the beginning of the document, you can put c:=0 and that takes care of the speed of light.

dik (Structural) · Answer 3 · 2023-05-20 02:23:54

Do you need to add fps? These are some of my definitions in SMath:

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

Sparweb (Aerospace) · Answer 4 · 2023-05-20 16:20:16

Mathcad has a trick that Smath doesn't (I think) where you can define constants anywhere in the sheet, making them universal.

Instead of X:1*m
You type X~1*m
You will see a three-line equal sign. The mathematical symbol for a constant definition.

That makes "X" mean 1 meter everywhere in the sheet. Using them at the bottom of the sheet can be bad practice if the next user of the sheet doesn't know it's hidden and tries to play with "X:2*m" at the top, because it will refuse to become 2 meters.

But in terms of unit definition like DIK does, it's great.

IRstuff (Aerospace) · Answer 5 · 2023-05-21 05:49:38

The ~ operator is very useful indeed; there are some times when I need to manually iterate a calculation, and so I can put the input variable next to the end result, change the input variable using the ~ and see the result right there.

TTFN (ta ta for now)
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dik (Structural) · Answer 6 · 2023-05-21 19:57:17

I declare the stuff, off the page at the beginning of the template sheet... it's there to view, but doesn't print... same with revision notes.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

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Mathcad Wishlist - Units definition control