Count number of particles within a given radius

I have a question regarding counting number of particles.

Lets say:

1. I create a box of domain 100x100 units.
2. I put 10000 random particles inside the box by using rand command.

Now what I want is the following:

I want to count the number of neighbour particles of each particle within radius 1 units. i.e each of my particles of 10000 random particles only interact with their neighbour who's distance is = or < 1.

Can anyone help !

[KSSV]

Are you trying to code SPH?

[Alakesh Upadhyaya]

No, I have an output of a simulation. The simulation contains particles of 2 types, type 1 and type 2. The file has following columns:

particle id particletype x-pos y-pos. Now I want to find all the neighbours of type 2 particles within radius 1 of each particles.

[Image Analyst]

OK so you have the location of each particle, but do you have its radius? Or did you mean distance to other nearest particle instead of radius?

Answer 1

[KSSV]

REad about knnsearch, rangesearch and inpolygon.

[Alakesh Upadhyaya]

Thank you, I did it using rangesearch.