Linear applications (like "ker"...)
01-25-2015, 04:11 PM (This post was last modified: 01-26-2015 06:31 PM by salvomic.)
Post: #1
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
Linear applications (like "ker"...)
hi need something like the menu "Linear Application" for matrices in HP50: image, ker, ismom, mkisom functions...
In Prime I can find only "ker()" function, for "kernel" (null space) and "mkisom()", like the HP 50g, but not "isom()" and "image()".

In CAS aren't the other functions, particularly "Image()"?
Is is possible to have them in another way?

Thank you,
Salvo
02-17-2015, 10:35 AM
Post: #2
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
RE: Linear applications (like "ker"...)
please, advise to write a little program to get the command image() like those in HP50g, to calc the image of a linear applications or its associated matrix :-)
Having a matrix, to reduce it (i.e rref()...), find vectors that are linear independent and that form a base...

Please, dr. Parisse, help.

I hope that developers would like to put image() in the next firmware upgrade of Prime, however.

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
02-17-2015, 12:41 PM
Post: #3
 parisse Senior Member Posts: 1,311 Joined: Dec 2013
RE: Linear applications (like "ker"...)
image(A) is rref(tran(A)). Indeed tran(A) puts the columns of A that spans image(A) in rows, then rref reduce the rows, and you get the basis with non-0 rows.
BTW, image and mkisom are Xcas commands.
02-17-2015, 01:45 PM (This post was last modified: 02-17-2015 01:55 PM by salvomic.)
Post: #4
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
RE: Linear applications (like "ker"...)
(02-17-2015 12:41 PM)parisse Wrote:  image(A) is rref(tran(A)). Indeed tran(A) puts the columns of A that spans image(A) in rows, then rref reduce the rows, and you get the basis with non-0 rows.

so simply! I didn't think, thank you
I'm defining a function, now.

Quote:BTW, image and mkisom are Xcas commands.

also ker(), if I'm not wrong; but in Prime I find only ker() and mkisom()...

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
02-17-2015, 04:14 PM
Post: #5
 Han Senior Member Posts: 1,882 Joined: Dec 2013
RE: Linear applications (like "ker"...)
If A is your original matrix, you can also simply use rref(A) to determine the pivot columns of A. The pivot columns of A form a basis for image(A). Parisse's solution is much more direct.

As for commands being available in xcas vs the HP Prime, there are many commands in xcas not available on the prime. The CAS in the HP Prime is not an exact duplicate of xcas; I do not believe this was the intended design (I could be wrong).

Graph 3D | QPI | SolveSys
02-17-2015, 04:28 PM (This post was last modified: 02-17-2015 04:29 PM by salvomic.)
Post: #6
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
RE: Linear applications (like "ker"...)
thank you Han.

Who, like me, come from HP 50g, perhaps would like to retrieve in Prime all that is in the other HP best calculator. Said that, I understand that not all in the CAS is also in the Prime, sure.
Only I would suggest to the Team of Developers of Prime don't omit some useful commands, perhaps simple but important, like image() or few others...

However the Parisse's solution it's ok for me (also your hints).

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
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