SIMULTANEOUS INVERSION OF THE VELOCITY AND ATTENUATION COEFFICIENT OFACOUSTIC-WAVE

An inverse problem for equations for acoustic-wave attenuation is solv ed by the optimization method. To increase the precision and efficienc y of solution, an adaptive algorithm with the variable number of param eters is proposed. Three adaptive methods of minimization - gradient m ethod, conjugate-gradient method, and Newton's method - are compared b y efficiency. It is demonstrated that the adaptive algorithm significa ntly increases the convergence of these methods. The increase is irreg ular and most pronounced for a conjugate-gradient method. This method is more efficient than the other two. On average, the adaptive variant requires 2-4 times less calculations than the nonadaptive one. The ad aptive algorithm increases the precision of environmental parameters f or any of the above three minimization methods.