code: public static ZMatrixRMaj diag(double... data ) {
          if( data.length%2 == 1 )
              throw new IllegalArgumentException("must be an even number of arguments");
  
          return diag(new ZMatrixRMaj(1,1),data.length/2,data);
      }
docs: <p>
  Creates a new square matrix whose diagonal elements are specified by data and all
  the other elements are zero.<br>
  <br>
  a<sub>ij</sub> = 0         if i &le; j<br>
  a<sub>ij</sub> = diag[i]   if i = j<br>
  </p>
  
  @param data Contains the values of the diagonal elements of the resulting matrix.
  @return A new complex matrix.