ACCEPTED SOLUTION
Accepted Solutions
I don't know whether this works in Prime, but it works in M13 and M14 (haven't tested M15).
There is an undocumented feature of local function that we can make use of to act as a global memory. If an array is defined before a local function definition, then that function can manipulate the array and store values that get retained between successive calls to the function. This capability is particularly useful for generating sequences, such as the Fibonacci sequence or random number generators such as the Mersenne Twister.
The Fibonacci functions given below allow the user to generate successive Fibonacci numbers simply by calling the function setfib and retrieve the current list using the function getfib.
Stuart
Stuart! Long time no see. I guess you didn't get washed away in the floods then 
Neat trick. I can confirm it works in MC15 too.
Neat trick. I can confirm it works in MC15 too.
And it even works in Prime 3, too. Just did the conversion.
No clue how it works and whats about the 1*v 
Ah hah! There is madness in my plan ... no, cunning in my plan, because on average the wind will evaporate the water! <smug> Of course, the windchill is probably going to be a problem, but ...
I can tell that you've been across the Pond for too long. You've forgotten that there is no relationship between any given UK weather property and any other property, nor is the same property even remotely autocorrelated in time. I've stood in an air traffic control tower, one half of which was encompassed in doom, gloom, cloud down to the ground, heavy rain & zero visibility and the other half was in bright blue sunshine and CAVOK - there was a classic front passing right through the middle of the tower and what amazed me was just how straight and long it was. In fact, thinking about it, my cunning plan has just blown itself away as there is no analytic relationship between water density or wind and height but Murphy's distribution function will ensure that, no matter where I am, I will always get the worst of wind and rain. 
Stuart
Recently, I spent several months trying to persuade one engineer that was using Excel to try SMath, which wouldn't even cost him anything. He kept saying "OK", but didn't even download it. Then one day, about a week ago, he was working on a problem in Excel that was giving him problems (guess what: some of them were unit problems!) so he asked me to do it in Mathcad for him. So I reminded him about SMath, and he finally tried it. The reaction? "Oh my God! This is just the tool I've been looking for for years!". I didn't say anything.
Maybe if PTC can advance Prime faster than a group of volunteers is advancing SMath (which is questionable) he might splash the money for Mathcad at some point.
My biggest problem at the moment with Mathcad, however, is that from my perspective it's effectively remained static from a capability point of view
In what way is retrograde motion "static"?
I haven't looked at SMath for a couple of years, so I've just downloaded it. I'm impressed with the integration of symbolic and numeric maths on the ODE example I looked at, as well as the hover and inspect results.
It's got some nice features. To get some of them you have to install plugins though. For example, the native 2D plots are even more inadequate than those in Prime, but there is a plugin that gives you excellent 2D plotting. There are some other holes too, such as no support for vectorization, no symbolic integrals. But for the price it can't be beat
I can't wrap my head around why Prime would even want to drop the original Whiteboard concept and go to a serial page format only,
You can make it go to the whiteboard format. There are some small icons at the bottom right of the screen.
