Variables
Mon, 04/20/2009 - 02:44
Hi,
Great app! I notice, though, that there doesn't seem to be a way of entering variables into an equation. For simple calculations, this is not really an issue, but if I want to create formulae for later references, defining my own variables would be useful. Also, a feature that would be nice, but absolutely not necessary, would be to be able to drag expressions around, i.e. shift a product from the numerator to the denominator in an expression. That way, one could really do some algebraic manipulations with this app.
As a calculator, it works great though! Thanks!
~ Roger
Mon, 04/20/2009 - 08:38
#2
Yes, there's no way to input variables (or annotations) right now for your own custom equations. This, along with being able to create and file equations in your own custom categories, is something I plan to implement eventually, but I want to make sure I do it in a way that doesn't clutter up the interface. Also, there's the issue of data persistence. I want to make sure that you have a means of backing up your custom equations and restoring them in the event of an accidental deletion of the application or other data loss. I don't want people to spend hours inputting equations to have them lost. When I have good solutions to these issues, I'll add that functionality in.
However, my immediate focus is improving the numerical calculation features by adding things like unit support.
Dragging of operations to new locations within the calculation is also on my to-do list. It's a little tricky, because you have to distinguish between the finger movement for scrolling and the drag operation, but I'm testing out a couple of ways of doing this.
Tue, 04/21/2009 - 13:21
#3
Units are important, but I would vote for user defined variables and user defined constants.
It is already possible to save a user defined formula with empty boxes (unnamed placeholders). It would seem to be pretty straightforward to add a separate editing window that would allow the user to label the boxes with variable names and annotations.
A different editing window for user defined constants. It would accept a name and a value and the name could be automatically displayed in the PI menu (which currently only displays pi and e).
Tue, 04/21/2009 - 14:30
#4
It would be a job for a desktop client, I think. It would cause far less interface problems (or at least different problems), and a convenient way to back up and restore data.
Is it possible to make a scroll gesture with one finger and a drag gesture with two fingers (or the opposite)? I don't know if it is easy to do, but it seems natural to me.
Tue, 04/21/2009 - 18:28
#5
Is it possible to make a scroll gesture with one finger and a drag gesture with two fingers (or the opposite)? I don't know if it is easy to do, but it seems natural to me.
The way I'm thinking about it is you tap and hold on an operation, which will pick it up, then move your finger to drag it to the new position. The difficulty is in managing this interaction while handling scrolling within the equation view.
Also, when cut-and-paste arrives, I plan on using Apple's support for that with these kind of editing operations (and then being able to paste LaTeX or plain text outside of the application, and vice versa). That may even work better than the tap-and-drag method.
Sun, 04/26/2009 - 00:55
#6
I think that user-defined variables is an absolute necessity, MUCH more important than unit support.
Lack of this feature makes the program useless for lots of common use cases like entering in electrical formulas (in my most recent experience, Vout=1.25*(1+(R2/R1)), for the output voltage of an LM317 voltage regulator.) I spent way too long searching the docs for a way to enter this formula in a reusable way like the presupplied equations. Finally I gave up in disgust and downloaded Formulaic instead. Your program has a prettier user interface, but lack of the ability to enter my own equations isn't just an inconvenience -- it's a showstopper. I simply can't use it for most of what I want a program of this type to do without that feature.
Sun, 04/26/2009 - 07:55
#7
I'm also hoping that custom variables will be enabled in the next update. I would really like to be able to play around with algebraic expressions in an easy way. I understand that numerical calculations constitute this app's main purpose, but with such a beautiful user interface, it would almost be a shame not to expand it into a general purpose, interactive equation editor. I am eagerly awaiting the next update.
~ Roger
Sun, 04/26/2009 - 16:43
#8
Okay, I guess I underestimated the interest in custom equation support. I'm readying a minor update, which fixes a few things and adds some enhancements to the editing operations, but I'll see if there's a way I can implement this soon.
Sun, 05/10/2009 - 15:37
#9
As an FYI, I just started beta testing a means of entering and editing custom variables within your own equations. An example of this interface is below:
Sun, 06/14/2009 - 22:26
#10
It took a little while, but this is now available as version 1.1 on the App Store.
Great app! I notice, though, that there doesn't seem to be a way of entering variables into an equation. For simple calculations, this is not really an issue, but if I want to create formulae for later references, defining my own variables would be useful.
Yep, I think that's important. You can't expect to have everything in the library.
...and I think that's a really cool idea. I wasn't missing it, but now you've mentioned it I want it ;-)