# Passing in a matrix as initial conditions versus ensemble parallel simulation in DifferentialEquations

**URL:** <https://discourse.julialang.org/t/passing-in-a-matrix-as-initial-conditions-versus-ensemble-parallel-simulation-in-differentialequations/90484>\
**Category:** Modelling & Simulations\
**Tags:** question, differentialequation\
**Created:** [November 19, 2022, 2:47am UTC](https://discourse.julialang.org/t/passing-in-a-matrix-as-initial-conditions-versus-ensemble-parallel-simulation-in-differentialequations/90484 "2022-11-19T02:47:49Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![kcqpo](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@kcqpo](https://discourse.julialang.org/u/kcqpo)\
**Post date:** [November 19, 2022, 2:47am UTC](https://discourse.julialang.org/t/passing-in-a-matrix-as-initial-conditions-versus-ensemble-parallel-simulation-in-differentialequations/90484/1 "2022-11-19T02:47:49Z")

</div>

What’s the difference between passing in a matrix of NxM (N is the number of states, and M is the number of conditions) initial conditions and using the ensemble method?

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [November 19, 2022, 7:15pm UTC](https://discourse.julialang.org/t/passing-in-a-matrix-as-initial-conditions-versus-ensemble-parallel-simulation-in-differentialequations/90484/2 "2022-11-19T19:15:09Z")

</div>

Solving it all at once with the same time steps vs independently with different stepping behavior. The latter is usually more efficient.