Hector, the indeterminate aka vine aka cordon goes on till frost, the determinate ends with a flower truss and usually sets all it's fruit in one go, The semi will have a flush of fruit , may ease off then have another but it will grow like an indeterminate till frost , it doesn't end in a flower truss. They are often bushy and wide. I prefer to give them lots of space, and although I do English prune on some tomatoes and US prune on others I let the semi have free reign unless it really gets out of hand. Some varieties of semi grow different to others, some are quite controlled and others are maniacs. Don't worry about the flowers, pretend it is funny indeterminate. What variety is it.