* This method returns three objects : The cartesian mesh geometrically equivalent to \a this (within a precision of \a eps) and a permutation of cells
* and a permutation of nodes.
*
+ * - this[cellPerm[i]]=ret[i]
+ *
* \param [out] cellPerm the permutation array of size \c this->getNumberOfCells()
* \param [out] nodePerm the permutation array of size \c this->getNumberOfNodes()
* \return MEDCouplingCMesh * - a newly allocated mesh that is the result of the structurization of \a this.