# How to create a sparse matrix obeying (-1,1) uniform distribution

**URL:** https://discourse.julialang.org/t/how-to-create-a-sparse-matrix-obeying-1-1-uniform-distribution/21527
**Category:** General Usage
**Tags:** question
**Created:** [March 6, 2019, 8:49am UTC](https://discourse.julialang.org/t/how-to-create-a-sparse-matrix-obeying-1-1-uniform-distribution/21527 "2019-03-06T08:49:47Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![xieximeng2008](https://avatars.discourse-cdn.com/v4/letter/x/a9a28c/32.png) [@xieximeng2008](https://discourse.julialang.org/u/xieximeng2008)
#### Post date: [March 6, 2019, 8:49am UTC](https://discourse.julialang.org/t/how-to-create-a-sparse-matrix-obeying-1-1-uniform-distribution/21527/1 "2019-03-06T08:49:48Z")

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I try to code

```julia
using SparseArrays
using Distributions
sprandn(100,100,0.3,Uniform(-1,1))

```

But it failed. So how to generate a sparse matrix obeying (-1,1) uniform distribution? Thanks

 ![34](https://global.discourse-cdn.com/julialang/original/3X/1/0/10ad9d32ac20e17936a3dab89af9b8791d60dcce.png)

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<div class="post-metadata">

### Author: ![yha](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/yha/32/3502_2.png) [@yha](https://discourse.julialang.org/u/yha)
#### Post date: [March 6, 2019, 3:36pm UTC](https://discourse.julialang.org/t/how-to-create-a-sparse-matrix-obeying-1-1-uniform-distribution/21527/2 "2019-03-06T15:36:15Z")

</div>

You need `sprand` rather than `sprandn`, and the last argument should be a function that maps `n` to a vector of `n` samples (though the docs don’t seem to say so anywhere).

```julia
sprand(100,100,0.1,n->rand(Uniform(-1,1),n))

```