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(DM42) Matrix exponential
08-21-2023, 07:03 PM
Post: #20
RE: (DM42) Matrix exponential
Hi Albert

note the below matrix is row oriented, which c, HP50g, DM42 calculators are using (fortran is column, I don't know about xcas, but I get different result than you)
For the 2x2 example , your reference
A= [[ -49, 24][-64 ,31 ] ]
= [[1, 3] [2, 4]] × [[ -1, 0] [0, -17]] x INV[[ 1, 3][2, 4]]
exp(A)=[[1, 3] [2, 4]] × [[ exp(-1) , 0] [0, exp(-17)]] x INV[[ 1, 3][2, 4]]
= [[ -0.735759... , 0.551819... ] [-1.471518..., 1.103638...]]
I can get full accuracy (31- 32 digits) on DM42.
But my implementation on HP50g using double binary floating point fails.

br Gjermund
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Messages In This Thread
RE: (DM42) Matrix exponential - Gil - 08-11-2023, 11:46 PM
RE: (DM42) Matrix exponential - Gil - 08-12-2023, 10:01 AM
RE: (DM42) Matrix exponential - Gil - 08-12-2023, 08:26 PM
RE: (DM42) Matrix exponential - Gil - 08-12-2023, 08:55 PM
RE: (DM42) Matrix exponential - Gil - 08-13-2023, 10:51 AM
RE: (DM42) Matrix exponential - Gil - 08-13-2023, 09:46 PM
RE: (DM42) Matrix exponential - Gil - 08-15-2023, 11:42 PM
RE: (DM42) Matrix exponential - John Keith - 08-16-2023, 12:01 PM
RE: (DM42) Matrix exponential - Gil - 08-16-2023, 12:45 PM
RE: (DM42) Matrix exponential - Werner - 08-23-2023, 07:16 AM
RE: (DM42) Matrix exponential - Gjermund Skailand - 08-21-2023 07:03 PM
RE: (DM42) Matrix exponential - John Keith - 08-27-2023, 04:46 PM
RE: (DM42) Matrix exponential - Gil - 08-23-2023, 09:09 AM
RE: (DM42) Matrix exponential - Werner - 08-24-2023, 01:14 PM
RE: (DM42) Matrix exponential - Gil - 08-28-2023, 08:57 AM



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