title: mapply basics? - how to create a matrix from two vectors and a function
body: <p>I am trying create a data.frame from which to create a graph.  I have a function and two vectors that I want to use as the two inputs.  This is a bit simplified, but basically all I have is:</p>
  
  <pre><code>relGPA &lt;- seq(-1.5,1.5,.2)
  avgGPA &lt;- c(-2,0,2)
  
  f &lt;- function(relGPA, avgGPA) 1/(1+exp(sum(relGPA*pred.model$coef[1],avgGPA*pred.model$coef[2])))
  </code></pre>
  
  <p>and all I want is a data.frame with 3 columns for the avgGPA values, and 16 rows for the relGPA values with the resulting values in the cells.</p>
  
  <p>I apologize for how basic this is, but I assure you I have tried to make this happen without your assistance.  I have tried following the examples on the sapply and mapply man pages, but I'm just a little too new to R to see what I'm trying to do.</p>
  
  <p>Thanks!</p>