To simulate with ModelSim distributed with Lattice Diamond:
cd vsim make test
An interactive ModelSim session is started using the make launch target.
The Make script can be used with "ModelSim Lattice FPGA Edition".
If you are using a different ModelSim distribution, then you may
need to compile and analyse the Lattice simulation libraries manually.
The models are installed with Diamond in
cae_library/simulation/vhdl.
Another option is to set TECH=0 in the Makefile to use the
technology-independent model.