Adjoint Di erentiation of Hydrodynamic Codes
نویسندگان
چکیده
Many problems in physics and modern computing are inverse problems problems where the desired output is known and the task is to nd the set of input parameters that will best reproduce that output in a hydrodynamics code hydrocode Optimiza tion methods tackle this type of problem and a central task in applying optimization methods is to be able to determine the gradient of the output with respect to the input parameters that are being adjusted Presented here is the authors progress through the use of adjoint di erentiation in obtaining those gradients in the case of some relatively simple hydrocodes
منابع مشابه
Adjoint Codes in Functional Framework
We show how to implement fun tionally the reverse, or adjoint strategy within the domain of Computational Di erentiation te hniques { tools permitting to ompute numeri ally, but exa tly (i.e. up to the ma hine pre ision) the derivatives of oded fun tions. The imperative oding of the reverse te hniques is awkward. It requires the reversal of the ontrol thread of the program, and it re omputes th...
متن کاملThe Data-Dependence Graph of Adjoint Programs
Automatic Di erentiation is a technique that permits generation of adjoint programs, which compute gradients. In scienti c computation, these gradients are a fundamental tool for optimization or data assimilation. Computation of a gradient is relatively expensive, and should therefore be optimized whenever possible. The study of these program optimizations is most often based on the data-depend...
متن کاملAutomatic Differentiation of Advanced Cfd Codes for Multidisciplinary Design
Automated multidisciplinary design of aircraft and other ight vehicles requires the optimization of complex performance objectives with respect to a number of design parameters and constraints. The e ect of these independent design variables on the system performance criteria can be quanti ed in terms of sensitivity derivatives which must be calculated and propagated by the individual disciplin...
متن کاملSharing Storage Using Dirty Vectors
Consider a computation F with n inputs independent variables and m outputs dependent variables and suppose that we wish to evaluate the Jacobian of F Automatic di erentiation commonly performs this evaluation by associating vector storage either with the program variables in the case of forward mode automatic di erentiation or with the adjoint variables in the case of reverse Each vector compon...
متن کاملADIFOR Generating Derivative Codes from Fortran Programs
The numericalmethods employed in the solution of many scienti c computing problems require the computation of derivatives of a function f R R Both the accuracy and the computational requirements of the derivative computation are usually of critical importance for the robustness and speed of the numerical solution ADIFOR Automatic Di erentiation In FORtran is a source transformation tool that ac...
متن کامل