# Video review of Pi Cubed

August 19, 2009

TheAppPodcast.com has posted a video review of Pi Cubed, which explores the features of the application from a layman's perspective. As a disclaimer, I commissioned the review, but the reviewer has been honest about other applications that he's looked at. It's worth viewing if you would like another perspective on the application.

## Comments

Galtonâ€™s Law expressed mathematically. can you add this ? it's a equation used in pedigree research I will for sure buy and people in my grop might also

thanks deab

I'll see if I can add it in for the next update. In the meantime, you can enter custom equations yourself, so if you have the full version you'll be able to enter in the equation and store it within your own custom equation library.

Unfortunately, you currently can only send the representation of the equation to your coworkers, not the equation that they'd be able to instantly import so they'd have it. I'm working on that.

Are there any plans to add algebraic equation solving capabilities, formulas, discrete/finite math, logic, graphing and other high level maths?

Symbolic math is a long-term goal of the application, but that won't be added within the next few months. Matrix and other complex operations will be added relatively soon, but my current focus is on improving the core numerical calculations.

In that vein, I'm not sure that integrated graphing will ever be a part of the application. There's only so much you can add to an interface before it becomes unwieldy, so it's my thinking that graphing will always be handled outside of Pi Cubed. Currently, that's handled by Grafly, but I'm investigating other possibilities.

Do you have any plans of including a constant library (HP graphing calcs had this feature) and it would provide a great resource for the development of equations. Also, graphic images of the equations would be extremely helpful too. This helps visualize the variables and understand the full equation.

Yes, I'm working on adding user-defined constants, but I wanted to add in units first (this is why I leave the physical constants as variables in the equations right now). As soon as I finish my work on unit support, they should make it in.

As far as graphing goes, I'm not sure that I'll ever add equation plotting, simply due to the limited interface space on the iPhone. If I can find a way to make it work without things getting too cluttered, I'll give it a shot. The desktop version of the application will have this functionality, whenever I am able to get it released.

That sounds great. I was going to ask the same question. Would be nice if, for example in the Eyring equation, the constants like R or K_Boltzman would already be predefined so that after entering of a temperature or an energy barrier the rate is given. Of course it is important that one is able to choose the desired untits of the constants in the equation. Also, regarding the units, I would be happy to see atomic units as well.

Btw, is a very nice program!

One thing that would be very nice and useful to add, is a way of numerically solving equations for a variable. For example, you would take the equation "W cos theta = Fn", fill out the W and Fn fields, and get a value for theta (or even a list of values, since there's obviously more than one in this case). Whenever there's only one variable left in the equation, you numerically solve for it.

As far as I can tell from the video (I haven't tried the lite version because I still have iPhoneOS 2.something for development purposes), right now the app can only calculate the right hand side of an equation.

This is a popular request, and something that I'm working on. Unfortunately, my day job has drawn me away for the last few months, and the undo / redo functionality I've been working on has taken longer than I expected. Hopefully, I'll be able to get that update out there soon so that I can work on features like this.

Is there, or is there any plan to create functionality that will enable test or quiz questions to be set for example:

Rearrange the following equation to make x the subject of the equation

Differentiate/integrate the following function

State the mathematical condition for resonance to occur in a half open pipe given the length of the pipe, \ell, and wavelength of sound, \lambda.

If it's symbolic math you're looking for, that's something that is in the long term plans for the application, but it will be a long while before I get that in.

As far as typesetting beyond simple math layout, I doubt I'll do anything like that. The application is tightly focused around mathematical expressions, and I want to keep the interface designed around that.

The mathematical expression is really hard. I admire you because you are amazingly smart. This is very edifying and real site.

Are you planning an IPAD release? I realize the current version looks OK on the IPAD in the 2x mode. However, I am curious if you are planning a new release with features that take advantage of the larger image size.

Yes, I'm working on that for the next update. I'm off at WWDC right now, but I'm hoping to get this update finally out soon.