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using jit.la.mult for rotation matrix : is this the expected behaviour ?


Vincent Goudard
March 13, 2012 | 1:30 am

hello folks,

I am trying to code a rotation matrix with jit.la.mult in complex (= 2 planes) mode, but I get the *weird* following behaviour : when I change the value of the first complex value in the rotation matrix, the output of the whole first line is changing.
(See patcher attached)
I would have expected only the first cell to change and being able to have as many complex rotation as the many cells in the matrix…

Is this the normal behaviour ? And if so what is it I do not understand ?
The documentation on jit.la.* objects is a bit light on the topic …
thanks for your help
Vincent

– Pasted Max Patch, click to expand. –

Vincent Goudard
March 13, 2012 | 1:49 pm

OK, I got confused, the behaviour is actually normal.

Nevertheless, it seems that the explanation given in the jit.la.mult help patcher is wrong.

In the patcher [p complex+float64], one can read :
"for two complex numbers (a, bi) and (c, di) the product is (ab-cd, (ad+bc)i)."

while it should be :
"for two complex numbers (a, bi) and (c, di) the product is (ac-bd, (ad+bc)i)."

Also, the jit.la.uppetri help patcher text shows : "The jit.la.determinant object converts a given input matrix to an upper triangular matrix".

… which is also confusing.
8-)

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