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eliminate command
11-24-2023, 01:26 AM
Post: #1
eliminate command
Dear Community,
Is there any command corresponding to eliminate command of XCAS in HP Prime.

Eliminating one or more variables from a list of equations
The eliminate command eliminates variables from a list of equations.
• eliminate takes two arguments:
– eqns, a list of equations.
– vars, the variable or list of variables to eliminate. The equations can be given as expressions,
in which case they will be assumed to be 0.
• eliminate(eqns, vars) returns the equations with the variables vars eliminated or an indication
that Xcas cannot eliminate them.
Examples
Assuming the variables used haven’t been set to any values:
> eliminate([x=v0*t,y=y0-g*t^2], t)
> eliminate([x+y+z+t-2,x*y*t=1,x^2+t^2=z^2],[x,z])
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11-25-2023, 06:31 PM
Post: #2
RE: eliminate command
eliminate in Xcas is based on an efficient Groebner basis engine that can handle double reverse lexicographic ordering (by double I mean order first with respect to the variables to be eliminated then with respect to other variables). I optimized this Groebner code several years for 64 bit processors. And unfortunately it fails on the arm 32 bits processor of the Prime, I made a check and it crashes on the Prime G1 (at least)/ I do not have an emulator where I could try to fix that efficiently (the hp "emulator" is not a real emulator, it is a simulator, it is using code compiled for amd64/x64 not for arm). This is sad, but running code calling Groebner basis code on a calculator is not recommended anyway because it would require large amount of RAM even for simple inputs...
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10-17-2024, 05:44 PM (This post was last modified: 10-18-2024 07:39 AM by amindanial.)
Post: #3
RE: eliminate command
(11-25-2023 06:31 PM)parisse Wrote:  eliminate in Xcas is based on an efficient Groebner basis engine that can handle double reverse lexicographic ordering (by double I mean order first with respect to the variables to be eliminated then with respect to other variables). I optimized this Groebner code several years for 64 bit processors. And unfortunately it fails on the arm 32 bits processor of the Prime, I made a check and it crashes on the Prime G1 (at least)/ I do not have an emulator where I could try to fix that efficiently (the hp "emulator" is not a real emulator, it is a simulator, it is using code compiled for amd64/x64 not for arm). This is sad, but running code calling Groebner basis code on a calculator is not recommended anyway because it would require large amount of RAM even for simple inputs...

Is there any hope to solve this issue at least for HP Prime G2?
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10-18-2024, 02:07 PM
Post: #4
RE: eliminate command
I do not have an emulator for the G2, which means I can not fix efficiently issues if they do not appear on the Prime simulator on the PC.
You can run resultant to eliminate one variable in a polynomial system.
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