# Is it possible to multiply with a derivative operator?

**URL:** https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914
**Category:** General Usage
**Created:** [September 18, 2019, 7:33pm UTC](https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914 "2019-09-18T19:33:28Z")
**Posts on this page:** 1
**Showing post:** 10

<div class="post-metadata">

### Author: ![chakravala](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chakravala/32/6832_2.png) [@chakravala](https://discourse.julialang.org/u/chakravala)
#### Post date: [September 18, 2019, 8:36pm UTC](https://discourse.julialang.org/t/is-it-possible-to-multiply-with-a-derivative-operator/28914/10 "2019-09-18T20:36:42Z")

</div>

Alright, well currently you can use my prototype implementation from [Leibniz.jl](https://github.com/chakravala/Leibniz.jl) (which will not be needed in the future as the feature will be built into Grassmann.jl itself)

```nohighlight
using Leibniz, DirectSum, SymEngine
import Leibniz: Monomial
printindices(V,D) = (io=IOBuffer();DirectSum.printindices(io,V,D,true);String(take!(io)))
Base.:*(d::Monomial{V,G,D,0} where G,r::Basic) where {V,D} = diff(r,symbols(Symbol(printindices(V,D))))
Base.:*(d::Monomial{V,1,D,1},r::Basic) where {V,D} = diff(r,symbols(Symbol((printindices(V,D)))))
x,y = symbols(:v1),symbols(:v2)
A = [x y^2; y^2 x*y]
b = [∂(ℝ^2,1),∂(ℝ^2,2)]

```

something like this should work with `SymEngine` at least

```nohighlight
julia> A*b
2-element Array{Any,1}:
 1 + 2*v2
       v1

```

is that what you wanted? as I said, `Leibniz` is a prototype for what will be available in `Grassmann`

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