code: public static void fill( DMatrix4x4 a , double v  ) {
          a.a11 = v; a.a12 = v; a.a13 = v; a.a14 = v;
          a.a21 = v; a.a22 = v; a.a23 = v; a.a24 = v;
          a.a31 = v; a.a32 = v; a.a33 = v; a.a34 = v;
          a.a41 = v; a.a42 = v; a.a43 = v; a.a44 = v;
      }
docs: <p>
  Sets every element in the matrix to the specified value.<br>
  <br>
  a<sub>ij</sub> = value
  <p>
  
  @param a A matrix whose elements are about to be set. Modified.
  @param v The value each element will have.