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+--- Thread: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 (/thread-6202.html)
Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - Arno K - 05-04-2016 10:24 PM
Today I came across the task of getting a matrix simplified with different ways to perform, one was M= [[2,0,0,0],[2,2,0,0],[1,-1,2,-1],[0,1,0,2]], a Schur decomposition was to be done and this is provided by the Prime.
As I want to check out the Prime's capabilities I tried to get the eigenvalues, easily computed by hand, all are 2, the Prime gives a warning ( "Low accuracy" ) and using EIGENVAL(M3), provides 4 values which can be rounded to 2.
Then I tried EIGENVV(M3) and the physical prime simply restarted, the PC-emulator halted (both latest firmware) and the Android-app (8151) crashed, too. Recalling M3 and EIGENVV(Ans) delivers: "Not invertible error: Bad Argument Value", contrary to Wolfram, saying [0,0,1,0] is an eigenvector and that is correct.
Arno
RE: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - parisse - 05-05-2016 05:08 AM
Crashed again because the Prime does not have exceptions, it returns a "not invertible error" on Xcas (this is expected because the matrix is not diagonalizable, therefore numeric diagonalization will fail while exact diagonalization works).
RE: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - compsystems - 05-06-2016 06:32 PM
MATHEMATICA
https://www.wolframalpha.com/input/?i=EIGENVALUES+(%5B%5B2,0,0,0%5D,%5B2,2,0,0%5D,%5B1,-1,2,-1%5D,%5B0,1,0,2%5D%5D)
[2,2,2]
TI68K
EIGVL([[2,0,0,0],[2,2,0,0],[1,-1,2,-1],[0,1,0,2]]) [enter]
[2,2,2]
hpprime
EIGENVAL([[2,0,0,0],[2,2,0,0],[1,-1,2,-1],[0,1,0,2]]) [enter]
"Low accuracy" then [2.00058131764,1.99961844696, 2.00018411644, 1.99961611895]
https://www.wolframalpha.com/input/?i=EIGENVALUES+(%5B%5B2,0,0,0%5D,%5B2,2,0,0%5D,%5B1,-1,2,-1%5D,%5B0,1,0,2%5D%5D)
Prime does not have exceptions???
So, why not incorporated?
RE: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - parisse - 05-06-2016 07:03 PM
You can get exact eigenvalues inside the CAS, even more jordan will return the Jordan normal form (not available on the ti).
Code:
p,j:=jordan([[2,0,0,0],[2,2,0,0],[1,-1,2,-1],[0,1,0,2]]); p*j*inv(p);RE: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - Arno K - 05-06-2016 09:21 PM
Well, I did not (really) bother about the prime not being able to produce the eigenvectors, what I wanted to say is: it CRASHED using EIGENVV(M3) where M3 is one of the built-in matrices filled with the data provided above here the warning: Matrix is not diagonalizable, try.... would be a workaround.
Arno
RE: Bug in EIGENVV in combination with built-in matrices M0..M9 in 10077 - parisse - 05-07-2016 06:51 AM
Of course it should not crash, it's now fixed in the source code.