Re: To convert and simplify units in tables (was:LIterate programming with calc (help))

[ypuntot]

Hi Ihor.
I'm null at elisp. Could you please refer to me a simple example of math 
operation and unit simplification in elisp?
Thanks :$

10 dic 2022 14:51:39 Ihor Radchenko :

> Ypo  writes:
> 
>> (defmath uconvert (v u)
>>   "Convert value V to compatible unit U."
>>   (math-convert-units v u))
>> 
>> 
>> But no luck, "cs" result is an ERROR. Is it feasible to get a value for
>> "cs" with no units?
> 
> Note that apart from Calc formula notation, you can use Elisp. That will
> avoid all the gotchas Calc has.
> 
> -- 
> Ihor Radchenko // yantar92,
> Org mode contributor,
> Learn more about Org mode at .
> Support Org development at ,
> or support my work at 

Re: To convert and simplify units in tables (was:LIterate programming with calc (help))

[Ihor Radchenko]

Ypo  writes:

> (defmath uconvert (v u)
>    "Convert value V to compatible unit U."
>    (math-convert-units v u))
>
>
> But no luck, "cs" result is an ERROR. Is it feasible to get a value for 
> "cs" with no units?

Note that apart from Calc formula notation, you can use Elisp. That will
avoid all the gotchas Calc has.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at .
Support Org development at ,
or support my work at 

To convert and simplify units in tables (was:LIterate programming with calc (help))

[Ypo]

#+TBLFM: $s=uconvert($W*$l/$Z,kg / cm^2)::$cs=uconvert($s_lim/$s, )

where uconvert is defined as:

(defmath uconvert (v u)
  "Convert value V to compatible unit U."
  (math-convert-units v u))


But no luck, "cs" result is an ERROR. Is it feasible to get a value 
for "cs" with no units?


Ok, it is enough to add any unit to uconvert, for example: 
$cs=uconvert($s_lim/$s,m). That simplifies units in adimensional parameters.


Best regards ;D

To convert and simplify units in tables (was:LIterate programming with calc (help))

[Ypo]

Hi

I have found an alternative solution to this problem:

Is it possible to express in a calc block some basic operations with 
variables and non-predefined units?



For example, if you wanted to build a code block that calculates how 
much money costs


a land with an Area of 300x300 m^2 at a price of 1 $/m^2.


Would it be something like this?

#+begin_src calc
  a = 300 m
  b = 300 m
  Area = a*b
  cost = 1 ($/m^2)
  A*c

#+end_src



The alternative way I am trying is using an org-table. It is not 
literate programming, but it is a spreadsheet with units ;D


| $ | a = 300 m    |
| $ | b = 300 m    |
| _ | Area |
|   | 9 m^2    |
| $ | cost = 1 USD/m^2 |
| _ | Payment  |
|   | 9 USD    |
#+TBLFM: $Area=$a*$b::$Payment=$Area*$cost

(Below "Area" cell it is the result of a*b, and below "Payment" cell it 
is the result of Area*cost)



Now, in a more practical case, I have some problems with units:

| $ | E = 2141404.05 kg/cm^2  |
| $ | s_lim = 275  N/mm^2  |
| $ | s_lim = 2800  kg/cm^2    |
| $ | W = 1 kg |
| $ | l = 65  cm   |
| $ | I = 25166  cm^4  |
| $ | Z = 1680  cm^3   |
| _ | s    |
|   | 386.90476 kg cm / cm^3   |
| _ | cs   |
|   | 7.2369231 kg cm^3 / (cm^2 kg cm) |
#+TBLFM: $s=$W*$l/$Z::$cs=$s_lim/$s

Below "cs" cell it appears 7.2... and this should be an adimensional 
number (no units). Is it possible to simplify those units?


I have tried with:

| $ | E = 2141404.05  kg/cm^2 |
| $ | s_lim = 275  N/mm^2 |
| $ | s_lim = 2800  kg/cm^2   |
| $ | W = 1 kg    |
| $ | l = 65  cm  |
| $ | I = 25166  cm^4 |
| $ | Z = 1680  cm^3  |
| _ | s   |
|   | 386.90476 kg / cm^2 |
| _ | cs  |
|   | #ERROR  |
#+TBLFM: $s=uconvert($W*$l/$Z,kg / cm^2)::$cs=uconvert($s_lim/$s, )

where uconvert is defined as:

(defmath uconvert (v u)
  "Convert value V to compatible unit U."
  (math-convert-units v u))


But no luck, "cs" result is an ERROR. Is it feasible to get a value for 
"cs" with no units?



Best regards