Units quick search feature added to SMath Studio.



Also Units added:
Revolution, Kilogram Force, Metric Ton Force, Ton Force and Kip.

Just few minor observations.

Do not understand why "Gravitational acceleration ('g)" is under "Viscosity, dynamic" in the "Dimension" list.

There is also a small typo in the Insert Unit dialog box - There is "Dimention" - should be "Dimension"

Regards,
Radovan

Hey there,

Haven't used this for a while, opened it up to play a little with maths.. And wham, update + units.
Pleasant surprise

Great work. Works fantastic
However, I stumbled across an inconvenient situation:


If I make a calculation that results in something squared (probably cubic etc. too), I can't *just* change the resulting unit. I have to enter a resulting unit... Squared...

Imagine using defined functions that return a result with an undefined power, having to go through each and setting the resulting unit to their respective powers :P... Imagine then changing the function

I think I made it clear ..

Regards,
Mike

PS.
Kudos. Showed it to some physics students I know, and they were baffled..

If you f.ex. enter "hr" into the little field after a calculation, it is possible to change the resulting unit..
But in my picture, it results to the rather inconvenient unit "s * hr"... Even though it makes loads of sense, it's not practical..

What I'd rather see when entering "hr" would be "hr^2". Ie. SMath compensates for the conversion to squared (thus removing the "s*..".

Here you go:

http://en.smath.info/for...t.aspx?g=posts&t=425

Have fun!


Regards,
Vlad.

Andrey,

Here is an example that I have simplified from a worksheet that I completed on the linear thermal expansion of steel pipes. You may use it (or not) as you want. It is a good, albeit quite simple, example of using units.

Linear Thermal Expansion

Also, in addition, it shows how to correctly work with temperature differences from relative temperature scales. (see these discussion threads for more info: Variable assignment bug, Unit Temperatures possible improvement )

Hope this is helpful,
Will

BTW: feel free to modify this example anyway you like.

Edited by user 24 June 2010 21:54:07(UTC)  | Reason: Not specified

I will be approaching units cautiously.

I have forgotten the details of all unit systems and some of my reference books are ancient. But I know what I am designing and building and understand the energies that I am working with and that they can be described differently. I purchased a Unit Conversion program years ago that has cut through the morass the different systems. This is when I realized that the concepts are more important than the units but once you put exponents on a value, most people start to loose grasp of the concept.

So this is what I ask. Let me turn off the automatic unit conversion of answers.

Just let SMath carry them through the equation.

In this simple calculation, I get a correct but totally useless answer.

5*'btu*6*'hr=1.08*10^5*'btu*'s


MathCad gives me an even more obnoxious number in Meters squared * Kilograms per Second.

If I gave that number to a customer, they would turn around and walk out the door.

If I make up my own units, SMath carries the units through perfectly.

5*'johnBTU*6*'johnHRS=30*'johnBTU*'johnHRS

and I get an understandable number... except for the john part.


I understand your concern for standardization and interoperability of worksheets between different users.
PTC MathCad did not implement this well, please don't follow their path.

More fun with Units:
5*'apples*4*'oranges=20*'apples*'oranges
6*'btu*5*'apples=30*'btu*'apples

Edited by user 02 January 2011 10:27:02(UTC)  | Reason: Not specified

Hi Radovan

Thanks

I was able to finally force units in my answer. It takes some practice using the arrow keys, the unit drop down box and the TAB key to select the unit. Practice, practice, practice!

I was also fianlly able to force it in MC.

I would still like the option to have the output units to automatically correspond to the input units and not spend the extra time to force anything.

I would also like the option to control scientific notation in the answer in the following ways:

Scientific Notation on or off.
Force exponents in answers to correspond with unit prefixes ... 10^3, 10^6, 10^-3 etc.

I design and build biomass combustion devices for home heating. I don't know what system my units belong to but they are real world units and my design references are in both metric and US units (even bushels of corn per day). Heat transfer units get really arcane ... BTU per square ft per inch per hour. Throw in some data in Watts per square meter and I have my hands full. This is why having the output units correspond to input units is important to me.

I have dropped out of two of the finest Engineering Colleges in the US because I was too slow with Calculus and could not do the rote memorization of the transformations required to pass. I always loved Math but have come to hate the way it is taught. This is why I am so excited about SMath. Years ago, I finally just decided to do Engineering rather than study it and for much less than the price of a years tuition built a very capable machine and welding shop.

Somehow I think posting my experience here might be of interest. I don't mean to be rude or demanding. Andrey is just amazing for what he has accomplished!

I just spent the last hour trying to create a worksheet incorporating the units feature.
My blueprints are in Decimal inches because that is how the machines in my shop are set up. My Heat Exchange Tables are in BTU per square foot. I tried to set the worksheet up to convert heat exchanger dimensions in inches to square feet. I now see the impossible challenge Andrey has trying to make the units feature meet every possible situation.

The end result was that I did not use the units feature. I labeled the units using plain text.

But I am very satisfied because I still have been able to easily document my calculations and have an interactive worksheet.

I think I will step out of this discussion on the units feature as I work with such a mess of different unit systems. I won't even dare request that Bushels of corn per day be incorporated into the program (Farmers up here really do burn corn for heat).

I could not figure out how to post a screen capture of this problem.

Hello John,

Do not worry about it . Just do not hesitate to post whatever you want. I can convince you that Andrey incorporated many things that users requested. However, it takes some time.

If you do not mind, I would suggest you to use units and do not give up. Just play with them and I am convinced that you will find the most convenient way for you. This is one of the greatest SMath feature.


As Ed suggested, visit the Wiki and see how to upload pictures there and make links to them in the posts.

Regards,
Radovan