I was comparing the two choices people face who want to do inference in nontrivial models. You can either write the model in an existing probabilistic programming language and get inefficient inference for free or you can write model+inference in something like Matlab. Here, you may be able to use libraries if your model is similar enough to existing models, but for many interesting models, this is not the case.
Ok, I was comparing the effort at the meta-level: providing tools for computing in a given subject area either by making a new language, or by making a new library in an existing language.
I was comparing the two choices people face who want to do inference in nontrivial models. You can either write the model in an existing probabilistic programming language and get inefficient inference for free or you can write model+inference in something like Matlab. Here, you may be able to use libraries if your model is similar enough to existing models, but for many interesting models, this is not the case.
Ok, I was comparing the effort at the meta-level: providing tools for computing in a given subject area either by making a new language, or by making a new library in an existing language.