title: Sequence of varying increments with R?
body: <p>I'm optimizing some various models, one of which is radialSVM using the <code>caret</code> package. I'm creating a tuning grid in preparation to cycle through a loop to find the best parameters to use for the model.</p>
  
  <p>One thing that would be extremely helpful is some sort of varying increment sequence. For example, I'd like to start with small parameter values incremented in small steps. The larger I go, the bigger steps I can take. I've found that small parameters do change the model quite a bit, so I'd like to explore them more carefully. </p>
  
  <p>It would be fantastic to have the sequence increment by some multiplier of the current step, say <code>x &lt;- x+5*x</code>. Is this possible with something that already exists, (like a creative use of <code>seq()</code>), or do I need to use a loop?</p>