# A few feature suggestions

Hi,

I grabbed Pi-Cubed when I saw it on MacResearch.com. Very nice piece of work. Hope it does well for you.

I have a few ideas that would make it a lot more useful (for me, at least. I'm an engineer, so you may see my bias here):

- There's no obvious way to clear a calculation, and start a new one.
- A search for the library (i.e. Where is the ideal gas law?)
- Radians! Nobody would use degrees in the equations you have. Surely.
- Powers of 10. Entering c in E = mc^2 is a bit of a pain at the moment.
- Physical Constants. Why am I even entering c?
- It would be nice to be able to define variables outside of the equation (esp. so that it can be latex type set)

e.g. nRT/P = V where n=3x10^6 T=300 P=101325. I guess it's a form of simultaneous equation. - It'd be great to be able to graph an equation w.r.t. a variable (big feature, not holding my breath)

...and as a side note, the title "Physics" in the equation library is a bit odd, as a lot of the other groups would also fall under that topic. Something like "Newtonian Mechanics" maybe.

At the moment, I think it shows more potential than it is useful, but I'm still glad I bought it. There's some really nice ideas in there.

Paul

What about clearing the entire equation by shaking the device? I don't think it would be too difficult to implement, although I may be wrong.

Actually, it looks like Apple is using shaking the device for undo in the 3.0 firmware update. I'll probably do the same when I start integrating 3.0 features into the application.

I would like to support Paul's suggestion about having trig functions in radians. The very definition of the sine function, for example, uses radians!

great program,

but like others I also have a few suggestions...

for example: lets take Pythagorean theorem a^2 x b^2 = c^2

it would be great if we could enter any 2 variables and the 3rd would be calculated,... not just the one right of equal sign, in this case "c", that would be great...

also,... it would be a great feature if we should be able to make presets for ourselves, using signs like you used in your templates (a, b,c,.. x,.....etc) also including explanations when tapped like in yours.

also something that I mentioned at the beginning, ability to make the equation on both sides of equal sign, using letters, not just numbers,.... and that any of them could be calculated if the rest of them entered,...

not to forget PC app, not just MAC

hope this makes sense LOL

anyway, thanks for a great App

I just remembered another one:

it would be great if users could upload the presets they made, for others to download it directly to iphone through your app...

thanks again

Igor

for example: lets take Pythagorean theorem a^2 x b^2 = c^2

it would be great if we could enter any 2 variables and the 3rd would be calculated,... not just the one right of equal sign, in this case "c", that would be great...

This is a popular request, but is tricky to do. Exact results would require symbolic math, which is a long-range goal of mine for the application, but won't be in there for a while. I may be able to do a numerical approximation, but again that could require some effort.

Unfortunately, I'm a Cocoa developer, so there's about zero chance that this application will appear on Android, Palm Pre, Windows Mobile, Windows, or Linux. In fact, it uses Apple-specific frameworks that have no equivalent on those platforms, so it would be impractical if not impossible to replicate this same functionality on anything other than the Mac or iPhone / iPod touch.

This is now supported in version 1.1, which just made it on the App Store. To set the default angle units, you just need to go to the Settings application and set the appropriate value within the Pi Cubed grouping.

I'm thinking the graphing is going to be external to the application, perhaps through a custom URL scheme with something like Grafly.

As it turns out, that's exactly what I did for version 1.1, which is now on the App Store.

Hi, I would like to say this is a good program, but I agree with Paul this program needs to have variable out side of the equation that can be changed for ease of calculation. Ex: a(5)/b=? Or =c and have below a=6 b=0.4 c= ? or c= variable. That would make it more usefull for me as an environmental engineer.

Thank you for your time.

I grabbed Pi-Cubed when I saw it on MacResearch.com. Very nice piece of work. Hope it does well for you.

I have a few ideas that would make it a lot more useful (for me, at least. I'm an engineer, so you may see my bias here):

- There's no obvious way to clear a calculation, and start a new one.
- A search for the library (i.e. Where is the ideal gas law?)
- Radians! Nobody would use degrees in the equations you have. Surely.
- Powers of 10. Entering c in E = mc^2 is a bit of a pain at the moment.
- Physical Constants. Why am I even entering c?
- It would be nice to be able to define variables outside of the equation (esp. so that it can be latex type set)

e.g. nRT/P = V where n=3x10^6 T=300 P=101325. I guess it's a form of simultaneous equation. - It'd be great to be able to graph an equation w.r.t. a variable (big feature, not holding my breath)

...and as a side note, the title "Physics" in the equation library is a bit odd, as a lot of the other groups would also fall under that topic. Something like "Newtonian Mechanics" maybe.

At the moment, I think it shows more potential than it is useful, but I'm still glad I bought it. There's some really nice ideas in there.

Paul

Clearing a calculation can be done by tapping on the equals sign (which selects the entire calculation) and deleting the selected operation. This isn't particularly well explained or obvious, so I apologize for that.

Search within the library is a good idea. I'll take a look at that (this might also be a nice iPhone 3.0 feature integration).

Without unit support as of yet in the numerical calculations, I had to make a choice as to the default trig angle unit. People had complained about it being radians, so I switched to degrees. Unit support should make that selectable.

Scientific notation is something that I am working on, but didn't have a clean enough implementation for 1.0. Agreed, it makes certain calculations cumbersome without that input format.

For physical constants, I might direct you to this forum thread. The problem comes down to the units of the physical constants. When I add unit support, all of these variables will be replaced by the numerical constants themselves.

As I discuss here, I have a couple of interface and data integrity issues that I want to resolve before implementing full custom equation input. It is coming, it just will be after I complete the numerical unit support.

I'm thinking the graphing is going to be external to the application, perhaps through a custom URL scheme with something like Grafly.

I think that it still has significant utility for doing numerical calculations right now, but I agree that a few additions would increase its usefulness for many people.