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fabifgon
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Hello,

I think pi cubed it's a very great app, but I think that needs calculate derivatives and integrals, and so edit and create categories in the built-in library and create new formulas in this library.

Thanks.

Brad Larson
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True symbolic math like you describe will take a little while to implement, and I don't see that making it into the application for at least another six months to a year. Currently, the calculation engine is geared entirely to numerical calculations, and that has been my primary focus.

You can create and categorize equations within your own equation library as of version 1.1. I wanted to keep that separate from the built-in library so that I'd be able to add or move equations in that library without messing up people's custom libraries. I'm going to leave the built-in library as read-only for that reason. If you have suggestions for ways to better integrate the custom and built-in equation libraries, I'd be glad to hear them.

fabifgon
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I think that the built-in library could be editable, and could be an option in pi cubed's settings menu to reset this library, and will be great and option in the app to export or import your library as LaTeX or plain text.

Brad Larson
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I'm working on the import / export functionality (export is easy, import not as much), because people will definitely want to be able to back up their custom equation database if they've spent quite a bit of time filling it out. It also would make it easy to import a large number of equations that you may have already typeset on your desktop.

Huntley
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Joined: 11/14/2009
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Hey there !

I just found Pi^3 and up front can i say what a great effort!
Nice work man - I will purchase the full version as soon as I save this post to help encourage you :-)
I'm a physicist by training and i work in technology development so I really understand the level of effort in making this.

I'm sure you have your own priorities - I'm going to wade in with my project manager hat on to say the following:

1) UNDO. Oh boy - i'm sure i will get used to the interface but so may times i replace the wrong thing and undo would save me over and over! One level of undo is fine - you know pretty fast when you screw up!

2) PASTE. If we can copy all or part of a stored equation can we please paste it into a new one? or another part of the same one... (pls paste the units with the qty - see below :-)

3) UNITS - I know this is a priority for you because of non-SI use, but how many of us have made the mm vs m mistake before? be honest - this is a really good idea!
In the USA it is simply essential - how many of you can convert slugs per square foot to pascals by yourself? or even know these are both a pressure ??!!
Units are also a VERY good way of making sure your equations are dimensionally correct - a great cross checker in it own right.
You could build up the units of any part using your current UI - have a tab for units, select the thing you want to define the units for and pick them off the list: kg, lb, g, mph, ms^-1 etc etc - the conversion factors are simple and a dimensional check helps you balance your equations :-) - pre defined constants have their units already eg light speed = 299^6 (ms^-1) (approx :-)

4) VARIABLES - would it be possible to use each screen as a worksheet? in the sense that you can define variable(s) which are then used in other equations on the same page. This could be entirely numeric - i'm not asking you to re-write mathematica!
If i could define say m=10, g=9.8, h=6 then pi^3 could evaluate mgh = .
This might be a great place to put in the unit conversion.
A line like: Roger = 34(kg) = xx(lb) - Pi^3 would evaluate the xx to 74.8

You would need the ability to start a new line but the zoom and scroll would let you get around the worksheet just fine as it is :-)
I get a bit confused by the display i must say - even if i define the result (RHS, after the = ) as say "gamma" as soon as it evaluates the gamma turns into a number.
The numeric result is necessary - that's what the app does!! and we DO want the answer.
How about a layout like:
"gamma" = equation = 3.87667290002.
You know what gamma's value is, and you can use it in other lines on the same worksheet - Pi^3 treats it like 3.87667290002 ie representative but numeric.

Sorry i went on - I do this for a living :-)
Love the app - would not bother otherwise !

Cheers!

Huntley.

Brad Larson
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User offline. Last seen 4 years 22 weeks ago. Offline
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Thanks for all of the suggestions. Some of the items, like units and paste support within the equation are things that I'll be working on for near-future updates.

Given the hardware limitations of screen size and memory on the iPhone, I'm not sure that I'll be looking to convert the application to using a worksheet-based interface any time soon. My focus is on enabling individual numerical calculations. However, I may find a way to make it practical.

As far as undo / redo, I almost have that ready:

It's taken me a few months to get it working right, and I just need a little more time to make sure my current implementation works in all cases.

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