(DM42) Matrix exponential

[Gjermund Skailand]

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