274 reputation
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visits member for 3 years, 4 months
seen Jan 10 at 23:04

Jul
2
awarded  Curious
May
13
awarded  Caucus
Mar
18
awarded  Yearling
Jan
12
answered Probability exercise without combinatorics
Jan
12
comment Equation of a sphere as the determinant of its variables and sampled points
Very clear. Thank you!
Jan
12
accepted Equation of a sphere as the determinant of its variables and sampled points
Jan
12
asked Equation of a sphere as the determinant of its variables and sampled points
Jan
5
comment What's the name of a parabola mapped onto a sphere?
I'm afraid I'm pretty naive in this area, but I can look-up terms I don't understand and research further once I'm pointed in the right direction and know the appropriate vocabulary. My background is in Computer Science. I regret that I haven't studied differential equations, although I have a basic understanding of dynamical systems. I don't have any experience with differential geometry and my experience with Tensors is limited to inertial tensors in 3d physical simulation.
Jan
4
accepted What's the name of a parabola mapped onto a sphere?
Jan
2
comment What's the name of a parabola mapped onto a sphere?
I think I'm more interested in the Riemannian version. The label alone is useful to me since it helps me look in the right direction. The image I posted illustrates an attempt to always treat the surface of the sphere as locally planar and then evaluate the next point of the parabola on this plane. Because it's a sphere, the curve will wrap around, but when the line overlaps itself, it is at a different point on the curve and also has its own local planar reference frame which may be rotated from before.
Dec
31
awarded  Commentator
Dec
31
comment What's the name of a parabola mapped onto a sphere?
Cool. I'm glad to see an answer after so long. The field of Algebraic Geometry is definitely new to me. It doesn't actually give a name to the generalization of geodesics to higher-degree polynomials, but maybe it doesn't need a name. I can't easily render curves described this way at the moment. Do you happen to have any intuition as to how these might compare with defining a portion of a curve as a parametrized interpolation between two arc segments?
Nov
3
comment Conjugation of Quaternions as Rotations in $\mathbb{R}^3$
I don't know the theory. And I don't know what "conjugacy map" means. But I do regularly use quaternions to represent 3d rotations. If the rotating quaternion is not normalized, it may scale the vector you're rotating. The vector itself, however, can be any length without any issues. But if it's a unit-length vector, then it happens to look just like a regular unit-length quaternion during the rotation, which probably makes it easier, in a text, to illustrate how the quaternion/conjugate sandwich multiplication produces a pure rotation of the augmented 3d vector.
Nov
1
comment Newbie Question: Probability of Life
@k.honsali I'm not sure what you mean by 'the equation for life'. No one would attempt to model something complex as a whole life in any complete sense. It's just intractable. To model something like timing/probability/cause of death, a Bayesian would look at actuarial tables to find the ways and ages that people die as well as any additional data about the person. The Bayesian could then take all known conditions of a person of interest and compare them to the conditions of people that died and come up with a probability of the person's death. They'd work for an insurance company.
Oct
31
answered Newbie Question: Probability of Life
Oct
31
asked Name this concept: Comparing equal sized vectors vs. comparing features
Oct
11
awarded  Nice Question
May
10
accepted Apply a fraction of a rotation matrix without extracting axis-angle
May
9
comment Apply a fraction of a rotation matrix without extracting axis-angle
@J.M. Hmm... true enough.
May
9
asked Apply a fraction of a rotation matrix without extracting axis-angle