title: forecast with data from a matrix in r
body: <p>I want to produce a forecast of a matrix.. 
  for e.g</p>
  
  <pre><code>&gt; x&lt;-ts(...,start=c(2009,1),frequency=12)
  </code></pre>
  
  <p>so.</p>
  
  <pre><code>       A       B        .    .  .        G
    2009/1    2314     1456             3021
    2009/2    2345     2351             2241  
         .       .        .                .
         .       .        .                .
         .       .        .                .
   2014/12    3210     3412             3199
  </code></pre>
  
  <p>to get the first column <code>x[,1]</code> the second <code>x[,2]</code>..
  now i want to forecast all the products (A,B,C,....,G) with one order.
  the forecast  method is holtswinter.
  so i guess it would be something like that:</p>
  
  <pre><code>for(i in 1:7)
  fit1[i]&lt;-hw(x[,i],h=12,model="additive")
  fit2[i]&lt;-hw(x[,i],h=12,model="multiplicative")
  </code></pre>