Set to an initial guess; |

, Compute and at with Algorithm 1; |

Perform wavelet transform for and level by level to |

* ** *
obtain and for , with and |

* ** *
being the wavelet transform at the th level |

* ** *
for and ; |

(4) Set and ; |

While |

* ** * |

* *Obtain a solution from using the CGD |

* *method with an initial value ; |

* *Prolongate through padding zeros to obtain an initial |

* *guess for at the next higher resolution, that is, |

* *; |

* *; |

* ** * |

(6) Solve with as an initial guess; |

(7) ; |

If (Define termination criterion ) go to ; |

* ** *
Else , output ** .** |