inv(matrix) * matrix does not give unity matrix? - A times inv(A) does not give unity matrix - Messages
#1 Posted: 9/9/2014 10:36:01 AM
Hello,
Maybe a minor issue, but I think this should be corrected. Result must be the unity matrix.
[ALBUMIMG]363[/ALBUMIMG]
Regards,
Radovan
Maybe a minor issue, but I think this should be corrected. Result must be the unity matrix.
[ALBUMIMG]363[/ALBUMIMG]
Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
#2 Posted: 9/9/2014 10:45:56 AM
Radovan, guess what the answer is...
Because A is defined symbolically.
Each use of A calls the definition and produces new random numbers.
It does not help to switch optimization to numeric, because that first generates the random number and then adds it to the zero matrix. Thus A becomes singular (all identical numbers.)
One might wish to define more precisely, what adding a random number to a matrix should give. First picking the number and adding it or first adding the call to all elements and then picking the numbers.
Because A is defined symbolically.
Each use of A calls the definition and produces new random numbers.
It does not help to switch optimization to numeric, because that first generates the random number and then adds it to the zero matrix. Thus A becomes singular (all identical numbers.)
One might wish to define more precisely, what adding a random number to a matrix should give. First picking the number and adding it or first adding the call to all elements and then picking the numbers.
Martin Kraska
Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx
#3 Posted: 9/9/2014 11:01:44 AM
I think you agree with me that this simple example reveals (again) the peculiarities of symbolic-numeric SMath problem
Regards,
Radovan
Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
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