# SymBandedMatrix indexing
**URL:** https://discourse.julialang.org/t/symbandedmatrix-indexing/10604
**Category:** New to Julia
**Created:** [April 29, 2018, 10:19am UTC](https://discourse.julialang.org/t/symbandedmatrix-indexing/10604 "2018-04-29T10:19:42Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)
#### Post date: [April 29, 2018, 10:19am UTC](https://discourse.julialang.org/t/symbandedmatrix-indexing/10604/1 "2018-04-29T10:19:42Z")
Hi,
I try to use BandedMatrices package and I can’t set values in the symmetric case:
```julia
using BandedMatrices
a=BandedMatrix{Float64}(10,1,1)
fill!(a,0.0) #OK
BandedMatrices.inbands_setindex!(a,12.0,1,2) #OK
b=SymBandedMatrix{Float64}(10,1)
fill!(b,0.0) #KO indexing not defined
BandedMatrices.inbands_setindex!(b,12.0,1,2) #KO indexing not defined
```
The documentation does not say much about symmetric matrices so I start to read the implementation but it is not trivial to me…
What would be the correct way to set values in symmetric banded matrices
Thank you for your help.
Laurent
---
### Author:  [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)
#### Post date: [April 29, 2018, 11:16am UTC](https://discourse.julialang.org/t/symbandedmatrix-indexing/10604/2 "2018-04-29T11:16:49Z")
Oops, I just realized that it is not a general Julia question and that I should post it directly on the BandedMatrices.jl package page. Sorry for the noise. Going from Tridiagonal to Banded is not such a large step…