diffus | two instances of any data structure

This is my first post here and I am not that experienced, so please excuse my ignorance.

I am building a Monte Carlo simulation in C++ for my PhD and I need help in optimizing its computational time and performance. I have a 3d cube repeated in each coordinate as a simulation volume and inside every cube magnetic particles are generated in clusters. Then, in the central cube a loop of protons are created and move and at each step calculate the total magnetic field from all the particles (among other things) that they feel.

At this moment I define everything inside the main function and because I need the position of the particles for my calculations (I calculate the distance between the particles during their placement and also during the proton movement), I store them in dynamic arrays. I haven't used any class or function,yet. This makes my simulations really slow because I have to use eventually millions of particles and thousands of protons. Even with hundreds it needs days. Also I use a lot of for and while loops and reading/writing to .dat files.

I really need your help. I have spent weeks trying to optimize my code and my project is behind schedule. Do you have any suggestion? I need the arrays to store the position of the particles .Do you think classes or functions would be more efficient? Any advice in general is helpful. Sorry if that was too long but I am desperate...

Ok, I edited my original post and I share my full script. I hope this will give you some insight regarding my simulation. Thank you.

Additionally I add the two input files

parametersDiffusion_spher_shel.txt

parametersIONP_spher_shel.txt

I add a sphere node, but when i rotate the node (from touching) the edges of the sphere are not smooth. Is there a way to fix this?

When rotating on X all is good, but in Y sphere is not smooth :(

My diffuse lighting doesn't seem to be working properly.

Fragment Shader:

After running two different CV-algorithms over an image (to find multiple occurences of a detail) they both deliver a list of results like the list below.

First algorithm delivers (tuples with left, top, width height):

I am currently implementing diffuse irridiance(A part of Image based lightning of PBR) in my game engine. I got to the point where I have to take an HDR Image and turn it into a cubemap. I am currently using a EquirectangularToCubemap shader and its working fine. I was able to project the HDR image to a (unit)cube. Now comes the part where I am stuck, I can't turn this cube to a cubemap. I tried using 1 TextureCube, 6 RenderTargetView's and a ShaderResourceView. My plan was to render the (unit)cube 6 times from different view projection with a FOV of 90 to capture the whole side in each of the render target, and lastly copy each of the output of the render target to the corresponding side of the Texture cube. I don't know how to do this ^.
NOTE: I am using DirextX11 as the rendering backend. Here is the pseudo code about my problem(which is not working)

I have this function named addShapes. I want it to create 3 shapes

I have this code that automatically colors all assembly components with random color. I asked a different question with this code before but this time, I want to ask if anyone could help To make this code colors only the selected assembly component? I hope someone can help me with this, I am still learning in API. Please see code below.

I'm new in Swift and ARKit. For some reason the SCNNode node I'm trying to display is not showing up. I'm working with SwiftUI. I defined in the next code block the function addNode that should render the node.

On loading the MTL file, the entire model is turning black. I have referred to this link and set the rbg parameters to 1 but that hasnt solved my issue.

three.js mtl loader renders black

Here is the code associated with it: