# Tullio without product

**URL:** <https://discourse.julialang.org/t/tullio-without-product/85708>\
**Category:** Modelling & Simulations\
**Tags:** tullio\
**Created:** [August 13, 2022, 4:38pm UTC](https://discourse.julialang.org/t/tullio-without-product/85708 "2022-08-13T16:38:22Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![qwerty](https://avatars.discourse-cdn.com/v4/letter/q/4491bb/32.png) [@qwerty](https://discourse.julialang.org/u/qwerty)\
**Post date:** [August 13, 2022, 4:38pm UTC](https://discourse.julialang.org/t/tullio-without-product/85708/1 "2022-08-13T16:38:22Z")

</div>

How can I replace the \* with a function?

```julia
@tullio c := a[i]*b[i]

```

a is an array of symbolic differential and b is an array of symbolic functions.  
I would like to get:

```julia
a[1](b[1])+a[2](b[2])

```

Thank you

---

<div class="post-metadata">

**Author:** ![mcabbott](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mcabbott/32/6603_2.png) [@mcabbott](https://discourse.julialang.org/u/mcabbott)\
**Post date:** [August 13, 2022, 5:13pm UTC](https://discourse.julialang.org/t/tullio-without-product/85708/2 "2022-08-13T17:13:26Z")

</div>

Should just work:

```julia
julia> a = [sin, cos]; b = [pi/6, pi/4];

julia> @tullio c := a[i](b[i])
1.2071067811865475

julia> sum(b .|> a)
1.2071067811865475

```