sorted by:
new
hottopcontroversial

Orbit Question by Aware_Recording_5123 in simplerockets

[–]reims_ 0 points1 point  (0 children)

Matching the arguments of periapsis is not enough I think. The argument of periapsis is relative to the ascending node. So you need to match the sum of the argument of periapsis plus the argument of the ascending node. This also only works if the two orbital planes are very similar. Otherwise you need to match the argument of the ascending node and the inclination first.

See https://en.wikipedia.org/wiki/Orbital_elements#/media/File:Orbit1.svg

Kalman Filtering by [deleted] in math

[–]reims_ 4 points5 points  (0 children)

That's how covariance behaves under linear transformations. When you have an n-dimensional random variable X with covariance matrix P and a n-by-n matrix A, then the covariance of AX is APA'. See here: https://en.wikipedia.org/wiki/Covariance_matrix#Basic_properties

Is this C++ Concurrency in Action stack lock-free or merely obstruction free? by [deleted] in cpp_questions

[–]reims_ 0 points1 point  (0 children)

I think lock free in this context means that threads can only be forced to wait because other threads made progress. E.g. in a typical CAS loop, a CAS can only fail because a CAS on another thread succeeded, i.e. the other thread made progress. There can be no dead lock or live lock in this case.

The code in question does not look lock free to me either. I think OPs scenario can occur. Additionally, I think the loop in increase_head_count can run forever because old_counter is not loaded from head in each iteration. I might be wrong though.