The more I use the WP34s, the more I love it. Nice work! It's really worthy!
Here are some suggestions that I have that could improve it a bit for me:
1)
Display less annunciators by default. By default the following ones are lit:
360 RPN BEG
The problem with this is, the display looks quite busy with lots of information while it isn't really needed.
I think the RPN one can be left unlit without problems, it's always on so it gives no information at all. It looks like the RPN symbol goes off while it calculates something. Maybe it can be inverted: It's off when not busy, and briefly turns on when the calculator is busy.
The 360 one isn't needed either. There's already a RAD symbol for radians, and the 'g' for gradians. So it's not needed to display another annunciator for degrees. You know it's in degrees if RAD nor 'g' are shown.
The BEG one is annoying. It indicates that the program pointer is at 000, but why do I need to see a BEG symbol forever in the screen for that even when not running programs? And doesn't the XEQ button already start running things from the start of a label? If you write all your things with a label, is the info where the program pointer is useful at all?
2)
In addition to combination and permutation, add Stirling numbers of the second kind. (http://en.wikipedia.org/wiki/Stirling_numbers_of_the_second_kind)
3)
Add prime factorization. This doesn't have to return all prime factors: Instead it could return two numbers, the lowest (or highest) prime factor, and the input number divided through that prime factor. By repeated application you can get all prime factors this way.
4)
In the manual, add more tables. It's easier to look certain things up in tables than plain text:
-A tabular listing of the meaning of each annunciator
-A tabular listing of each keyboard key (including the f, g, h functions of course) with a short description of its function and PDF link to the page where it is explained in more detail.
-In the section about display and modes, also have a table of the modes and a short description of their meaning, in the same order as they appear in the mode menu. E.g. if the short description of 2COMPL would just say "2's complement", I would already immediately know what it does, and know that it does not mean "complex number notation somehow involving a 2".
5)
In the manual, under complex operations, say that you enter imaginary part, then ENTER, then real part. Currently, the manual says
"The key CPX is employed as a prefix for calling complex functions. E.g. CPX COS calls the complex cosine, and it is displayed and listed as CCOS"
It would be good if it said how to enter and read complex numbers somewhere at that point.
6)
If you enter 1..2, have "1/2" instead of "1 0/1". I don't think anyone ever needs to enter a fraction of '0/1', so it's a bit of a wasted shortcut now :). I already know that .1.2 gives 1/2.
7)
Why does it bother adding 0/1 or /1 behind integers when in fraction modes?
8)
Correct me if I'm wrong, but there doesn't seem to be a button to toggle between fractional and decimal point notation? If the screen is displaying 1/2, is there no button to show it as 0.5? Maybe I'm just missing it. But going to the 'mode' for this is an overly long procedure in any case. The quickest way I discovered is pressing './,' twice in a row, but it's weird that changing an international setting would be the interface to this, and the button to switch to fractional again is on the opposite side of the calculator (the ab/c at the top).
The HP35s has the FDISP button to toggle between fractional and decimal. Some Ti's have an 'F<>D' button for this.
Also:
If you enter a fraction, it goes to fraction display mode.
If you enter a decimal value, it doesn't go back to decimal display mode.
I think your choice of display mode should be independent of how you enter numbers... If you're in decimal display mode and enter 1/2, it could be displayed as 0.5, since you didn't ask it to switch to fraction mode. The opposite is already true now: if you enter 0.5 while in fraction mode, it displays it as 1/2 instead of as what you entered.
9)
Entering binary base mode seems easy. Going back to scientific numbers appears to be a lot harder though, going to the mode menu, choosing base there, and guessing that entering 0 there will make things normal again. Maybe if you press the '2' button while already in base 2, or the 8 button when already in 8, and so on, could toggle this off and go back to floating point numbers?
Or maybe it's already possible with some easy way, in that case I missed it, sorry.
10)
loggamma function.
11)
Examples in the manual could be nice!
12)
The following are huge feature requests and I guess they aren't there for a reason (limitations etc...): numerical differentiation, matrix and vector math (multiply, determinant, invert, cross product, ...), solvers like linear equations, quartic function, ...
As you can see, the suggestions are for things that are way less worse than the problems of the 35s, so this means I find the 34s really really good. Thanks for all the work put into this!
Edited: 28 Aug 2011, 6:12 a.m. after one or more responses were posted