title: Read 2D indexes and tuple from Execl sheet
body: <p>I have tried to define Useduration as the 3D array but I did not know how to define the tuple elements. I have received an error&quot; float of 2 dimensions not supported for sheet&quot;. is there a way to read it from excel?</p>
  <pre><code>`   {string} sources=...;
  
   range time=1..Time; 
  
  tuple useduration {
   float frequency;
   float Averageduration;
   }
  useduration Useduration[time][sources]=...;
  
  
  dat.file
  
  
  sources=7;
  Time=2;
  Useduration= [
            [&lt;7.2,0.67&gt;,&lt;0.6,5&gt;,&lt;7.2,0.67&gt;,&lt;2,3&gt;,&lt;0.28,1&gt;,&lt;0.31,1&gt;,&lt;0.4,1&gt;],
            [&lt;7.2,0.67&gt;,&lt;0.6,5&gt;,&lt;7.2,0.67&gt;,&lt;2,3&gt;,&lt;0.28,1&gt;,&lt;0.31,1&gt;,&lt;0.4,1&gt;]]`
  </code></pre>