title: Error in model selection (gamm4) dredge function (MuMIn R package): family not recognised, model skipped
body: <p>I am trying to do model selection for generalized additive mixed models (made using <a href="http://cran.r-project.org/web/packages/gamm4/gamm4.pdf" rel="nofollow">gamm4</a> using the <a href="http://cran.r-project.org/web/packages/MuMIn/MuMIn.pdf" rel="nofollow">MuMIn</a> package in R.
  I am essentially trying to follow <a href="https://r-forge.r-project.org/scm/viewvc.php/*checkout*/pkg/inst/doc/gamm.pdf?revision=91&amp;root=mumin&amp;pathrev=91" rel="nofollow">this</a> piece of literature for model selection with MuMIn and gamm4.</p>
  
  <p>I am creating a model with 9 variables, and a random individual effect - which looks likes this:</p>
  
  <pre><code>library(gamm4)
  library(MuMIn)
  SouthFull = gamm4(OtoWidth ~ s(Ages) + 
                   LagFinFSLdat_AnnEsts +
                   FSL_months_Feb +
                   LagFSLdat_Annual +
                   LagFSLdat_Spring +
                   LagFSL_months_Oct+
                   FinFSLdat_SummerDat +
                   FinFSLdat_AutumnDat +
                   LagFSL_months_Nov , random = ~(1|FishName), data = South)
  </code></pre>
  
  <p>But when I try to use the <code>dredge</code> function, it fails with the error message:</p>
  
  <pre><code>(dd &lt;- dredge(global.model=SouthFull))
  Error in dredge(global.model = SouthFull) : result is empty
  
      In addition: There were 50 or more warnings (use warnings() to see the first 50)
      &gt; warnings()
      Warning messages:
      1: In gamm4::gamm4(...) : family not recognized (model 1 skipped)
      ...
      50: In gamm4::gamm4(...) : family not recognized (model 50 skipped)
  </code></pre>
  
  <p>Is this due to a problem with MuMIn not recognizing the gamm4 model family?</p>
  
  <p>Full code &amp; data can be found at my <a href="https://github.com/emboylen/EBHonoursThesis/tree/master/8.%20Modelling/StackOverflowHelp" rel="nofollow">GitHub repository</a> and the specific issue is in the code <a href="https://github.com/emboylen/EBHonoursThesis/blob/master/8.%20Modelling/StackOverflowHelp/gamm_analysis.R" rel="nofollow">gamm_analysis.R</a>, with the specific warnings found at line 81. </p>
  
  <p>Thank you in advance</p>