To create adjacency matrices and edge lists, follow these steps:
- Load Meetup.com user information from the meetup_users.Rdata file. This creates a data frame called users which has the variables, (user_id and group_id):
- Create a sparse matrix with groups on the rows and users on the columns with TRUE on each (group_id,user_id) position, where the group has the user as a member. If you have a large number of users, this step will take a long time. It also needs a lot of memory to create a sparse matrix. If your R session freezes, you will have to either find a computer with more RAM or reduce the number of users and try again:
> library(Matrix) > grp.membership = sparseMatrix(users$group_id, ...