A novel gravity assist space pruning(GASP)algorithm based on image tools is proposed for solving interplanetary trajectory optimization problem.Compared with traditional GASP algorithm,the concept of image is introduc...A novel gravity assist space pruning(GASP)algorithm based on image tools is proposed for solving interplanetary trajectory optimization problem.Compared with traditional GASP algorithm,the concept of image is introduced to avoid missing interesting solutions with appropriate number of function evaluations.Image tools allow us to evaluate the objective function in regions in place of points and provide an effective way to evaluate the forward and backward constraints for the multi-gravity assist trajectory optimization problem.Since the interesting solutions of the interplanetary trajectory optimization problem are often clustered in a small portion of the search space rather than being overall evenly distributed,the regionwise evaluations with image tools make the little large interval with the proper Lipschitzian tolerances sampling effective.The detailed steps of the proposed method are presented and two examples including Earth Venus Mars(EVM)transfer and Earth Venus Venus Earth Jupiter Saturn(EVVEJS)transfer are given.Finally,a comparison with solutions given by the literature demonstrates the effectiveness of the proposed method.展开更多
Compiler optimizations play a crucial role in achieving high processor performance by improving the efficiency of the machine code they generate through better algorithms and strategies.These optimizations ultimately ...Compiler optimizations play a crucial role in achieving high processor performance by improving the efficiency of the machine code they generate through better algorithms and strategies.These optimizations ultimately increase program execution efficiency.Over the past few decades,numerous compiler optimizations have been integrated into compilers,addressing research topics such as instruction scheduling and register allocation.However,selecting the optimal combination of compiler optimization options from a vast number of possibilities remains a challenging task.We proposed a Fast Compiler Autotuning Framework(FCAF),leveraging the systematic application of Design of Experiments(DoE)methods to rapidly narrow down the search space,aimed at efficiently enhancing the effectiveness of auto-tuning optimizations.FCAF achieves performance improvements comparable to state of the art tuning tools while significantly reducing tuning time on LoongArch and X86 platforms.Moreover,we used the orthogonal array design method to select a universal set of compilation options and applied these to the SPEC CPU 2006 benchmark suite.When compared to the GCC-O2 baseline,it increases by 3.89%for integer tasks and by 15.27%for floating-point tasks in benchmark scores.Further validation with real-world HPC applications confirms consistent performance gains.展开更多
基金supported by the National High Technology Research and Development Program (863)of China (2012AA121602)the National Natural Science Foundation of China(11078001)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (20133218120037)the Fundamental Research Funds for the Central Universities under Grant(NS2014091)
文摘A novel gravity assist space pruning(GASP)algorithm based on image tools is proposed for solving interplanetary trajectory optimization problem.Compared with traditional GASP algorithm,the concept of image is introduced to avoid missing interesting solutions with appropriate number of function evaluations.Image tools allow us to evaluate the objective function in regions in place of points and provide an effective way to evaluate the forward and backward constraints for the multi-gravity assist trajectory optimization problem.Since the interesting solutions of the interplanetary trajectory optimization problem are often clustered in a small portion of the search space rather than being overall evenly distributed,the regionwise evaluations with image tools make the little large interval with the proper Lipschitzian tolerances sampling effective.The detailed steps of the proposed method are presented and two examples including Earth Venus Mars(EVM)transfer and Earth Venus Venus Earth Jupiter Saturn(EVVEJS)transfer are given.Finally,a comparison with solutions given by the literature demonstrates the effectiveness of the proposed method.
文摘Compiler optimizations play a crucial role in achieving high processor performance by improving the efficiency of the machine code they generate through better algorithms and strategies.These optimizations ultimately increase program execution efficiency.Over the past few decades,numerous compiler optimizations have been integrated into compilers,addressing research topics such as instruction scheduling and register allocation.However,selecting the optimal combination of compiler optimization options from a vast number of possibilities remains a challenging task.We proposed a Fast Compiler Autotuning Framework(FCAF),leveraging the systematic application of Design of Experiments(DoE)methods to rapidly narrow down the search space,aimed at efficiently enhancing the effectiveness of auto-tuning optimizations.FCAF achieves performance improvements comparable to state of the art tuning tools while significantly reducing tuning time on LoongArch and X86 platforms.Moreover,we used the orthogonal array design method to select a universal set of compilation options and applied these to the SPEC CPU 2006 benchmark suite.When compared to the GCC-O2 baseline,it increases by 3.89%for integer tasks and by 15.27%for floating-point tasks in benchmark scores.Further validation with real-world HPC applications confirms consistent performance gains.
