Select3 decides if a particular transition matches the selection criteria based on the line strength and line opacity in a given medium. To do that select3 requires a model of the medium (temperature, pressure, node spacing), chemical composition and boundary conditions. Only 1D models are supported at the moment. Select3 processes one transition at a time working in two modes: opacity and synthesis. In the first mode it computes line opacity, compares it to the reference (e.g. bf and ff opa...