newRPL - Wiki examples for PEEK, POKE and NEWOB commands

[Claudio L.]

(09-25-2021 05:45 PM)JoJo1973 Wrote:  

(09-24-2021 01:52 PM)Claudio L. Wrote:  I think a more productive contribution to the wiki would be a tutorial with examples on how to use the multiple equation solver, which is very different from the 50g and 99% of users don't even know it's there.
I'd like to see examples, with single and multiple equations, as well as with constraints using inequalities to show how powerful it can be.

I'm collecting examples beginning from this old post

https://www.hpmuseum.org/forum/thread-97...#pid101856

but when I began experimenting I've found some difficulties: for example I can't get to solve this linear system:

a + x - 3 y + z = 2
-5 a + 3 x - 4 y + z = 0
a + 2 y - z = 1
a + 2 x = 12
(courtesy of Wolfram Alpha)

The solution is a=22/17 x=91/17 y=84/17 z=173/17 but MSOLVE can't converge: I've used {0 0 0 0} {12 12 12 12} as searching range and I got {0 0 0 0} and {-2 0 -1 -12} as residuals

If I constrain the four variables to be >0 I get {2.9999... 5.9646... 6.2512... 15.2711...} (I don't include the residuals.

I've also tried inverting the order of the searching range or adding >0 constraints, but to no avail.

A system of three equations fails to converge too, but a 2 equation system seems to work.

Interesting, I'm investigating why it does not converge.