Initialize the parameter: set , , , set the initial PSR; |

, discretize the model into a uniformly tetrahedral-element mesh; |

Establish the linear system equation , and solve it with TNIPM; |

**While** and |

Select those elements satisfy to form the new PSR based on the solution at current |

mesh level; |

Perform local mesh refinement and interpolate the new PSR to the next finer mesh; |

*k*++; Form and solve the new system equation with TNIPM at the th mesh level; |

**End while** |