absolutely - based on your comment yesterday, I've created SYSTEMML-1444 as a placeholder.
Regards, Matthias On Thu, Mar 30, 2017 at 1:23 PM, <dusenberr...@gmail.com> wrote: > Great, we should definitely add this to the 1.0 release in order to allow > for more expressivity in our DML, and to allow for the cleanup of existing > DML that has had to code around this, such as the `nn` library. > > I will add a JIRA (or search for one) and tag it for 1.0. > > -- > > Mike Dusenberry > GitHub: github.com/dusenberrymw > LinkedIn: linkedin.com/in/mikedusenberry > > Sent from my iPhone. > > > > On Mar 29, 2017, at 4:18 PM, Matthias Boehm <mboe...@googlemail.com> > wrote: > > > > Well, this would indeed be a very useful extension - I've actually seen > > many use cases, where new users ran into issues with simple expressions > > like X[i,i] = foo(). In the general case, the problem with UDFs is that > > they can have - in contrast to builtin functions - multiple returns. > These > > multiple returns would translate to HOPs with multiple outputs, which in > > turn cannot be represented with our current HOP DAG representation > because > > a HOP represents an operation and the characteristics of a single output, > > but potentially with many consumers. This is also the reason why builtin > > functions with multiple outputs (i.e., lu, eigen, qr) are internally > mapped > > to FunctionOps with the same restrictions. > > > > However, we could actually allow UDFs with a single output in > expressions. > > This would require a generalization of how results variables are bound > but > > should not take too much effort. Additional it would require a full pass > > through the compiler to remove any assumptions that FunctionOps always > > appear as DAG root nodes. Bottom line: We could realistically add it to > our > > feature list for the 1.0 release. > > > > Regards, > > Matthias > > > >> On Wed, Mar 29, 2017 at 3:55 PM, <dusenberr...@gmail.com> wrote: > >> > >> Currently, it is not possible to use UDFs within an expression. I.e. > I'd > >> like to be able to use something like `out = (-1/2) * > >> util::my_function(x)`. This would of course extend to more elaborate > >> expressions. Also, note that we *are* able to use built-in functions > >> within expressions. > >> > >> I think it would be good to allow for this. Are there any issues that > >> would make this difficult? > >> > >> -Mike > >> > >> -- > >> > >> Mike Dusenberry > >> GitHub: github.com/dusenberrymw > >> LinkedIn: linkedin.com/in/mikedusenberry > >> > >> Sent from my iPhone. > >> > >> >
