<p>The R package <b>optimParallel</b> could be helpful in your case. The package provides parallel versions of the gradient-based optimization methods of <code>optim()</code>. The main function of the package is <code>optimParallel()</code>, which has the same usage and output as <code>optim()</code>. Using <code>optimParallel()</code> can significantly reduce optimization times as illustrated in the following figure (<code>p</code> is the number of paramters). 
<a href="https://i.stack.imgur.com/AEsr4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AEsr4.png" alt="enter image description here"></a>
See <a href="https://cran.r-project.org/package=optimParallel" rel="nofollow noreferrer">https://cran.r-project.org/package=optimParallel</a> and <a href="http://arxiv.org/abs/1804.11058" rel="nofollow noreferrer">http://arxiv.org/abs/1804.11058</a> for more information. </p>
Parallel optimization in R
<p><a href="https://stackoverflow.com/questions/3757321/moving-beyond-rs-optim-function">This question</a> came at the right time, as I'm struggling with optimization as well. I am aware of the different "normal" optimization routines in R, and I am aware of parallel packages like snow, snowfall, Rmpi and the likes. Yet, I didn't manage to get an optimization running in parallel on my computer. </p>

<p>Some toy code to illustrate :</p>

<pre><code>f &lt;- function(x) sum((x-1:length(x))^2)
a &lt;- 1:5
optim(a,f)
nlm(f,a)
</code></pre>

<p>What I want to do, is to parallelize the optim() function ( or the nlm() function, which does basically the same). My real function f() is a lot more complicated, and one optimization round lasts about half an hour. If I want to run a simulation of 100 samples, that one takes ages. I'd like to avoid writing my own Newton-like algorithm for parallel computing, so I hope somebody could give me some hints on how to use parallel computing for complex optimization problems in R.</p>

<hr>

<p><em>I reckon this problem is of a different nature than the one in the related question. My request is specifically directed towards parallel computing, not some faster alternative for optim.</em></p>