[VA] New updates available in my HP site [Latest is Update #39, Sep 22]

[Valentin Albillo]

      
Hi, all:

I've just made available Update #21 at my HP site, namely the following 8 files (this makes 578 files in all which you can see and/or download for free):

• Note: I'll appreciate it if very much if you would please refrain from posting anything to this thread, so that it only contains the update announcements and listings themselves and nothing else. If you want to comment something please create another thread or PM me for any questions or comments you want addressed. Thanks.

     
2020-10-07:   Update #21   (8 files, including one new Article):

       HP Article VA047 - Boldly Going - Eigenvalues and Friends.pdf  (click to see or download)  in HP Calculator Articles

• 15-page article, featuring a subprogram, PCHAR, which deals with an advanced functionality very frequently needed in all sort of disciplines in Science, Engineering and Computing, yet not covered at all in the HP-71 Math Pac ROM, namely the task of computing all eigenvalues real and complex of an arbitrary real or complex square matrix.
  
  Subprogram PCHAR is very short (6 lines, 271 bytes) yet capable of quickly and accurately computing the Characteristic Polynomial of an arbitrary NxN real or complex square matrix in a format ready for computing all its real and complex eigenvalues with a single call to MAT..PROOT or PZER, so you get the task done using just two statements: calling PCHAR and executing MAT..PROOT or PZER.
  
  Additionally and as a big bonus, it also computes real/complex determinants and inverse matrices with accuracy far exceeding in some significant cases what the assembler-code MAT..INV, MAT..SYS and DET keywords can achieve (none of which can compute complex determinants, by the way), and at no extra cost whatsoever either in memory usage or computing time. For instance, it will exactly invert my "Mean Matrix" AM#7 without batting an eyelid.
  
  Many relevant, fully worked-out and commented examples included, as well as a detailed discussion on how to convert PCHAR to a binary subprogram or LEX keyword.

       
And last but not least, there's also the following files (click on any of them to see or download):

3 Selected HP Threads:

      HP Thread VA031 - 2003-11-04 - 15c or 32s which is better.pdf
      HP Thread VA032 - 2003-11-07 - 49gplus first impressions.pdf
      HP Thread VA033 - 2003-11-10 - Re Therapy Please repeat after me.pdf

4 Selected FractVal images:

      Misc Picture VA218 - Gravitational Waves - VF171206AI.jpg
      Misc Picture VA229 - Seaweed - VF180215AG.jpg
      Misc Picture VA238 - Scaping - VF171123BH.jpg
      Misc Picture VA245 - Cushion - VF171109BD.jpg

• Note: I'll appreciate it if very much if you would please refrain from posting anything to this thread, so that it only contains the update announcements and listings themselves and nothing else. If you want to comment something please create another thread or PM me for any questions or comments you want addressed. Thanks.

V.