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location Chemnitz, Germany
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Sep
13
revised Jacobian matrix of the Rodrigues' formula (exponential map)
added 24 characters in body
Sep
13
answered Optimizing Cholesky factorization for multiple sparse matrices with same nonzero pattern
Sep
13
answered Jacobian matrix of the Rodrigues' formula (exponential map)
Sep
7
awarded  Autobiographer
Sep
4
revised Finding the intersection point of many lines in 3D (point closest to all lines)
Ported to latex for a more math appropriate style
Sep
4
suggested suggested edit on Finding the intersection point of many lines in 3D (point closest to all lines)
Sep
4
awarded  Commentator
Sep
4
comment Finding the intersection point of many lines in 3D (point closest to all lines)
+1 I tried to work on the distance equation and derive it, but I completely forgot about Lagrange identity. Perfectly simple now.
Sep
4
comment Finding the intersection point of many lines in 3D (point closest to all lines)
Are you sure your computation of the distance is correct? The dot product computes the cos of the angle, whose sin we want, therefore we need the cross product (or rather it's norm) instead of the dot product.
Sep
3
comment Why composite transformations are multiplied to the right side?
@xEnOn Just to clarify, your example was badly-chosen, as OpenGL uses column vectors. But maybe you know this yourself and it was just a thought experiment.
Sep
2
answered Orthogonal matrix over cross product
Sep
1
comment How to calculate the x/y coordinate of F in this diagram (geometry)
@Emperorlou If it helped in some way up-voting is appreciated (or maybe even accepting, as it's exactly the solution you came up with, in a format more appropriate to math.stackexchange).
Sep
1
revised How to calculate the x/y coordinate of F in this diagram (geometry)
edited body
Sep
1
comment How to calculate the x/y coordinate of F in this diagram (geometry)
This formula is not more exact than mine, it is exactly mine, transformed from vector algebra into programming (guess how dot and $\cdot$ and len2 and $\|\cdot\|^2$ are related to each other?). But I have to admit I had a little error in my solution so you might not have seen the similarity at first (corrected it already). Even if you searched for a programming solution, it is not really hard to transform vector algebra into programming, especially when you already have functions for the dot product and the vector norm and as we're on math.se, your answer is not really neccessary.
Aug
31
revised How to calculate the x/y coordinate of F in this diagram (geometry)
edited body
Aug
31
answered How to calculate the x/y coordinate of F in this diagram (geometry)
Aug
29
revised Quaternion for an object that to point in a direction
deleted 265 characters in body
Aug
29
revised Quaternion for an object that to point in a direction
added 265 characters in body
Aug
29
answered Quaternion for an object that to point in a direction
Aug
25
comment The Euclidean norm ||r|| of a rotation
@seven_swodniw up-voting is always appreciated.