Issue with running beam example

[karthik-codex]

Hello, thank you for sharing the project! I was having trouble running the built in example cases. I am new to Taichi so the code is a bit difficult for me to follow yet. I get the following errors when I try to run the beam model. the code goes untill it says "now we begin to assemble the sparse matrix" and then terminates with this error

and I get a lot of these warning before the simulation terminates.