title: R nls Different Errors occur
body: <p>I'm new in R programming and I don't get a solution to an error which occurs when I use the nls Function. 
  I try to fit  the data from an ecdf (values are extracted and saved in y) to this function model with four parameters:</p>
  
  <pre><code>fitsim &lt;- nls(y ~ exp(-(((a-Abfluss)/(c*(Abfluss-b)))^d)), 
             start = list( a=max(Abfluss), b=min(Abfluss), 
                           c=3, d=1))
  </code></pre>
  
  <p>When I start the nls Function these error occurs:</p>
  
  <pre><code> Error in numericDeriv(form[[3L]], names(ind), env) : 
    Fehlender Wert oder etwas Unendliches durch das Modell erzeugt
  </code></pre>
  
  <p>which means there is a missing value ore some value with infinity is generated through the model. 
  My vectors Abfluss and y have both the same lengths. Aim is to get the parameter estimation. 
  Maybe the problem is, that the model only works under this conditions:
  c>0, d>0, b&lt;=Abfluss&lt;=a.
  I try already  the <code>na.rm=True</code> command. Then another error appears:</p>
  
  <pre><code> Error in model.frame.default(formula = ~y + Abfluss, na.rm = TRUE) : 
    Variablenlängen sind unterschiedlich (gefunden für '(na.rm)')
  </code></pre>
  
  <p>which means, the Length of variables are different. </p>
  
  <p>I appreciative for every kind of help and advice. </p>
  
  <p>For a better understanding I attach my whole code with whole data:</p>
  
  <pre><code>time&lt;-c(1851:2013)
  Abfluss&lt;-    c(4853,4214,5803,3430,4645,4485,3100,4797,4030,3590,5396,9864,3683,4485,4064,3420,5396,
          4895,3931,4238,3790,3520,4263,5474,3790,4700,5109,4525,4007,6340,4993,6903,8160,3600,3480,3540,
          3540,4565,3333,7764,  
          4755,7940,3112,3169,4435,5365,9422,3150,10500,4512,3790,4618,6126,3769,3704,
           5938,5669,4552,5458,5854,4867,6057,4783,5753,5736,4618,6091,5820,5007,7984, 4435,
           4645,7465,5820,5988,6022,4300,6062,3302,4877,4586,5275,4410,3174,4966,4939,4638,
           5541,5760,6495,5435,4952,4912,6092,5182,5820,5129,6436,6648,3063,5550,5160,4400,
           9600,6400,6380,6300,6180,6899,4360,5550,4580,3894,5277,7520,6780,5100,5430,4550,
           6620,4050,4560,5290,6610,8560,4943,6940,4744,6650,5700,7440,6200,4597,3697,7300,
           4644,5456,6302,3741,5398,9500,6296,5279,5923,6412,6559,6559,5891,5737,5010,5790,
           10300,4150,4870,6740,7560,8010,5120,8170,7430, 7330,5900, 11150)
  
  
  #EV4-Distribution
  dEV4 &lt;- function(x, a, b, c,d) {
  m&lt;-exp(-(((a-Abfluss)/(c*(Abfluss-b)))^d))
  return(m)
  }
  
  #Simulation example
  Sim&lt;-dEV4(Abfluss,a=max(Abfluss),b=min(Abfluss), c=3, d=1)
  dEV4cdf&lt;-cbind(Abfluss,Sim)
  
  #Empirical cdf
  p = ecdf(Abfluss)  
  y&lt;- p(Abfluss) #Extracting of cumulated probabilities
  m&lt;-cbind(Abfluss,y)
  
  #plot EV4 and ecdf
  plot(dEV4cdf, type="p",main="EV4")
  plot(ecdf(Abfluss), add=T)
  
  #Fitting EV4 nls
  fitsim &lt;- nls(y ~ exp(-(((a-Abfluss)/(c*(Abfluss-b)))^d)), 
            start = list( a=max(Abfluss), b=min(Abfluss), 
                          c=3, d=1), na.rm=TRUE)
  </code></pre>