The system of linear equations produced by the fem is solved by conjugate gradient ( cg ) algorithm, which is associated naturally with finite element problems because both finite element and conjugate gradient use similar minimization procedures 有限元法產(chǎn)生的線性方程組使用共軛梯度算法求解。共軛梯度(cg)法與有限元法聯(lián)系的十分自然因?yàn)閮烧叨际遣捎孟嗨频淖钚』^程。
And the system of linear equations produced by the fem is solved by element-by-element conjugate gradient ( ebe-cg ) algorithm, which is associated naturally with finite element problems because both finite element and ebe-cg use similar minimization procedures 而且,有限元法產(chǎn)生的線性方程組使用ebe-cg算法求解具有很好的發(fā)展前景,如將ebe-cg并行計算應(yīng)用于地球物理電法勘探有著巨大的市場和經(jīng)濟(jì)效益。
The results of numerical experiments, using the four-dimensional variational data assimilation system of the nonhydrostatic mesoscale model mm5, show that : the tangent linear model and adjoint model conducted by keeping the " on-off " switches the same as the basic state, can provide a good approximation of the first-order information to the nlm perturbation and a good descent direction for the minimization procedure; switching on and off at every other time step in the kuo cumulus parameterization scheme do n't impact the convergence rate of cost function; the existence of the switches do n't impact improvement to the mm5 model rainfall prediction because that not only specific humidity, but also wind, temperature and pressure are assimilated into the model 非靜力中尺度數(shù)值模式mm5的四維變分資料同化系統(tǒng)進(jìn)行的數(shù)值試驗(yàn)結(jié)果表明:“開關(guān)”變量保持與基態(tài)一致,所構(gòu)造的切向線性模式能夠提供關(guān)于非線性模式擾動的一階近似,伴隨模式所計算的梯度值能夠?yàn)樽钚』^程提供較好的下降方向;郭氏降水參數(shù)化方案中對流每隔一個積分步的交替發(fā)生并不影響目標(biāo)函數(shù)最小化的收斂速度;“開關(guān)”變量的存在也不影響將風(fēng)、溫度、氣壓和比濕結(jié)合起來同化對mm5降水預(yù)報準(zhǔn)確性的提高。