www.SwissMicros.com

GETKEY behaves erratically on the first row of keys (not the menu keys).
The real DM42 returns 1-6 for the row S+ to XEQ, and doesn't work for the menu keys (which is a pity, BTW)
The DM42 skin returns 1-6 for the menu keys and 2192 for S+, 2072 for 1/X etc.

Cheers, Werner

in Free42 (and the DM42) you can store up to 14 characters per register instead of only 6, using the following utilities to transform up to 14 characters to the X register (A2X) and its inverse (X2A) 00 { 77-Byte Prgm } 01>LBL "A2X" 02 ALENG 03 14 04 X>Y? 05 X<>Y 06 25600 07 0 08>LBL 03 09 % 10 ATOX...

It’s a printout from the Dm42 itself, not compatible with the program import. To import, use the .raw file.
Cheers, Werner

0. Abstract My ultimate goal is to draw a chess board. To achieve this in a modular fashion, we'll need tools to draw lines horizontally and vertically, use these to draw a grid, and then be able to fill half of the grid cells with a shading pattern. So, without further ado: 1. HLINE X Y Z T In: n ...

Show us your code, please? And that site will simply use N+k-digit arithmetic and constants to get to the precision requested (N) ie. they'll use gamma to N+k digits to guarantee the result is accurate to N digits. eg. for x=-30 the largest summation term is about 2.7e10 so an extra 10 or 11 digits ...

in my second-to-last post, 'extended precision' was but an example - that's why I said 'i.a.' - it's the resulting accuracy that counts.
And yes, all of that applies to the complex case as well. A DOT product of 2 complex vectors is obtained using 4 real dot products.
Cheers, Werner

We spoke of this before, can't remember whether it was here or at the hpmuseum.
There is a way to use FMAs to implement dot products, and obtain a result that is as accurate as if you used double precision.
I'll see if I can find it again,
Werner

Werner, do you know exactly which functions in the HP-42S use special-case logic for 2x2 matrices? I know DET does - it simply evaluates ab-cd in 15-digit precision. The others, I'll perform some tests. And what about higher-precision dot products? Obviously DOT, but matrix-matrix multiplication is...

Thomas Okken wrote: ↑

Tue Feb 12, 2019 10:58 am

• More accurate 2x2 matrix operations
• More accurate dot product using FMA

Yes!!! As this is something the real 42S does, as well (albeit not with FMAs)
Cheers, Werner

Perhaps you should read the first post in this thread before replying..
This is about RPN on the DM42, and of course Joe's remarks are also entirely accurate, as usual.
(well, except for Z=9 which should've been T=9

Cheers, Werner