Recent content by skyflashings

Find a nonzero 3x3 matrix A such that Ax is perpendicular to [1,2,3] for all x in R3 A vector perpendicular to [1, 2, 3] could be, say, [-2, 1, 0]. But what would be a general approach to finding a solution that would satisfy all x? Thanks!

Ah, yes you are right. I wasn't thinking of taking the cross between the vector and a vector 'in the direction of' the line. Thanks very much!

Hi! Any help would be appreciated! Give the equation of a plane containing the line r = i + 2j + 3k + t(i - j + k) and is parallel to vector v = -i + 2j + 3k. I'm using this as reference. My guess is to treat the problem similar to finding an equation of a plane which contains a...

Ok, I see how it unfolds now. One of the reasons I wanted to get my final form is that I only have a distribution for P(H), P(J|H), P(G|L,H), and P(L|H) and there is a conditional independence assumption that P(J|H)=P(J|G,L,H). So, I need to find P(H|J, G, L) in terms of those. If I...

I am not sure if I am doing this correctly, so please check my attempt: I have four discrete random variables: G, H, J, L Say, I want to find P(H|J, G, L). Then can I write as P(H|J, G, L) = P(J, G, L|H)*P(H) = P(J|G, L, H)*P(G|L, H)*P(L|H)*P(H) Are those equivalent? I can't find an...

Ah, sorry I didn't make that clear. It's in 2 dimensions (longitude and latitude).

I will try to be brief, so please bear with me! I have a Matlab program which simulates a particle's movement over time in a certain ocean. The details of this implementation aren't really important, but basically I create about ~300 particles near each other and place them at a certain...

Yes, I was quite surprised to see how quickly the result was computed! In the path simulation, the particle spins around a loop in the current about three times and then exits off to the right. But if I use a smaller time step dt the particle stays to spin nearly 6 times or more before...

I just finished the implementation of taking the spline on the gradient matrix for RK4 and it works wonderfully. A very smooth path is made, but the path is still relatively similar to my Euler implementation. Unfortunately, I was hoping to get drastically different results. Thank you so much...

Ok, I'll try that approach, thanks again.

If I interpolate first, I get a single height value as a result right? How can I apply a gradient across that value in relation to the rest of the matrix? Do I somehow add it into the original matrix and do a gradient from there?

I see. So perform the gradient on the interpolation, not the other way around. That certainly makes sense. I really appreciate the direction, and your time in explaining it to me. I'm thoroughly impressed :)

I believe you have just pointed me in the right direction! Actually, the Matlab program created the gradient automatically for me. However, when looking around for interpolation methods in MATLAB I came across interp2, which will interpolate for you when you give it an original discrete...

Thank you so much for replying. I'm starting to feel like I'm getting a better grasp of it. However, I have a question I hope you can help me with. For the functions u and v as you described, how can I find those slopes? All I have is a 2-d matrix with number values at each x,y position. I...

Hi, I am trying to apply the fourth order Runge-Kutta integration method to a problem but I'm not sure exactly how to do it. I have a matrix which represents a coordinate system (x, y) with varying degrees of height at each point. Using Matlab, I made a matrix with a gradient (u and v...