| 8 | 1/1 | 返回列表 |
| 查看: 2284 | 回復: 7 | |||||
yuanjian1987木蟲 (正式寫手)
|
[求助]
分數(shù)階微分方程Predictor-corrector PECE,程序怎么運行呢?
|
|
附件是老外編寫的程序,但是我不會運行,誰能舉個例子運行一下呢? 比如 D^q1=x^2+xy; D^q2=-x^2-2y; fdefun需要單獨編一個m文件嗎? 里面有好多function,需要將它們單獨編一個m文件嗎? Description of FDE12 FDE12 solves an initial value problem for a nonlinear differential equation of fractional order (FDE). The code implements the predictor-corrector PECE method of Adams-Bashforth-Moulton type described in [1]. [T,Y] = FDE12(ALPHA,FDEFUN,T0,TFINAL,Y0,h) integrates the initial value problem for the FDE, or the system of FDEs, of order ALPHA > 0 D^ALPHA Y(t) = FDEFUN(T,Y(T)) Y^(k)(T0) = Y0(:,k+1), k=0,...,m-1 where m is the smallest integer greater than ALPHA and D^ALPHA is the fractional derivative according to the Caputo's definition. FDEFUN is a function handle corresponding to the vector field of the FDE and for a scalar T and a vector Y, FDEFUN(T,Y) must return a column vector. The set of initial conditions Y0 is a matrix with a number of rows equal to the size of the problem (hence equal to the number of rows of the output of FDEFUN) and a number of columns depending on ALPHA and given by m. The step-size H>0 is assumed constant throughout the integration. [T,Y] = FDE12(ALPHA,FDEFUN,T0,TFINAL,Y0,H,PARAM) solves as above with the additional set of parameters for the FDEFUN as FDEFUN(T,Y,PARAM). [T,Y] = FDE12(ALPHA,FDEFUN,T0,TFINAL,Y0,H,PARAM,MU) solves the FDE with the selected number MU of multiple corrector iterations. The following values for MU are admissible: MU = 0 : the corrector is not evaluated and the solution is provided just by the predictor method (the first order rectangular rule); MU > 0 : the corrector is evaluated by the selected number MU of times; the classical PECE method is obtained for MU=1; MU = Inf : the corrector is evaluated for a certain number of times until convergence of the iterations is reached (for convergence the difference between two consecutive iterates is tested). The defalut value for MU is 1 [T,Y] = FDE12(ALPHA,FDEFUN,T0,TFINAL,Y0,H,PARAM,MU,MU_TOL) allows to specify the tolerance for testing convergence when MU = Inf. If not specified, the default value MU_TOL = 1.E-6 is used. FDE12 is an implementation of the predictor-corrector method of Adams-Bashforth -Moulton studied in [1]. Convergence and accuracy of the method are studied in [2]. The implementation with multiple corrector iterations has been proposed and discussed for multiterm FDEs in [3]. In this implementation the discrete convolutions are evaluated by means of the FFT algorithm described in [4] allowing to keep the computational cost proportional to N*log(N)^2 instead of N^2 as in the classical implementation; N is the number of time-point in which the solution is evaluated, i.e. N = (TFINAL-T)/H. The stability properties of the method implemented by FDE12 have been studied in [5]. [1] K. Diethelm, A.D. Freed, The Frac PECE subroutine for the numerical solution of differential equations of fractional order, in: S. Heinzel, T. Plesser (Eds.), Forschung und Wissenschaftliches Rechnen 1998, Gessellschaft fur Wissenschaftliche Datenverarbeitung, Gottingen, 1999, pp. 57-71. [2] K. Diethelm, N.J. Ford, A.D. Freed, Detailed error analysis for a fractional Adams method, Numer. Algorithms 36 (1) (2004) 31-52. [3] K. Diethelm, Efficient solution of multi-term fractional differential equations using P(EC)mE methods, Computing 71 (2003), pp. 305-319. [4] E. Hairer, C. Lubich, M. Schlichte, Fast numerical solution of nonlinear Volterra convolution equations, SIAM J. Sci. Statist. Comput. 6 (3) (1985) 532-541. [5] R. Garrappa, On linear stability of predictor-corrector algorithms for fractional differential equations, Internat. J. Comput. Math. 87 (10) (2010) 2281-2290. Copyright (c) 2011-2012, Roberto Garrappa, University of Bari, Italy garrappa at dm dot uniba dot it Revision: 1.2 - Date: July, 6 2012 |

榮譽版主 (文壇精英)
![]() |
專家經(jīng)驗: +518 |
|
alpha:FDE的階次,必須為正. fdefun 是標量T和向量Y定義的指向矢量場FDE的函數(shù)函數(shù)句柄,F(xiàn)DEFUN(T,Y) 必須返回一個列向量。. t0,tfinal: 參數(shù)t的初始值、終值. y0:一個矩陣,其行等于該問題的大。ㄒ驳扔谛蠪DEFUN的輸出數(shù)) param:參數(shù)個數(shù). mu:校正迭代參數(shù)選擇參數(shù). MU = 0 : the corrector is not evaluated and the solution is provided just by the predictor method (the first order rectangular rule); MU > 0 : the corrector is evaluated by the selected number MU of times; the classical PECE method is obtained for MU=1; MU = Inf : the corrector is evaluated for a certain number of times until convergence of the iterations is reached (for convergence the difference between two consecutive iterates is tested). The defalut value for MU is 1 mu_tol:控制誤差. h:從N = ceil((tfinal-t0)/h) 看,h是時間跨距,N是評估解的時間點的數(shù)目。 FDE12詳見 http://www.mathworks.cn/matlabce ... ferential-equations |
|
本帖內容被屏蔽 |
|
本帖內容被屏蔽 |
木蟲 (正式寫手)

新蟲 (初入文壇)
木蟲 (知名作家)
|
你好,請問Diethelm的書(Springer 2010)全名是The analysis of fractional differential equations: An application-oriented exposition嗎?沒有搜到,能否分享一下,謝謝 發(fā)自小木蟲Android客戶端 |
木蟲 (知名作家)
| 8 | 1/1 | 返回列表 |
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 295求調劑 +5 | 1428151015 2026-03-27 | 6/300 |
|
|---|---|---|---|---|
|
[考研] 265求調劑 +8 | 小木蟲085600 2026-03-27 | 8/400 |
|
|
[考研] 070300求調劑306分 +3 | 26要上岸 2026-03-27 | 3/150 |
|
|
[考研] 316求調劑 +5 | Pigcasso 2026-03-24 | 5/250 |
|
|
[考研] 材料求調劑 +8 | @taotao 2026-03-21 | 8/400 |
|
|
[考研] 求調劑 +5 | 蘆lty 2026-03-25 | 6/300 |
|
|
[考研] 086000生物與醫(yī)藥292求調劑 +6 | 小小陳小小 2026-03-22 | 9/450 |
|
|
[考研] 一志愿天津大學339材料與化工求調劑 +3 | 江往賣魚 2026-03-26 | 3/150 |
|
|
[考研] 打過很多競賽,085406控制工程300分,求調劑 +3 | askeladz 2026-03-26 | 3/150 |
|
|
[考研] 334分 一志愿武理-080500 材料求調劑 +4 | 李李不服輸 2026-03-25 | 4/200 |
|
|
[考研] 347求調劑 +4 | L when 2026-03-25 | 4/200 |
|
|
[考研] 0854電子信息求調劑 324 +4 | Promise-jyl 2026-03-23 | 4/200 |
|
|
[考研] 一志愿吉林大學材料與化工303分求調劑 +4 | 為學666 2026-03-24 | 4/200 |
|
|
[考研] B區(qū)考研調劑 +4 | yqdszhdap- 2026-03-22 | 5/250 |
|
|
[考研] 311求調劑 +3 | 冬十三 2026-03-24 | 3/150 |
|
|
[考研] 求調劑 +6 | 研研,接電話 2026-03-24 | 7/350 |
|
|
[考研] 環(huán)境學碩288求調劑 +8 | 皮皮皮123456 2026-03-22 | 8/400 |
|
|
[論文投稿] 急發(fā)核心期刊論文 +3 | 賢達問津 2026-03-23 | 5/250 |
|
|
[考研] 求助 +5 | 夢里的無言 2026-03-21 | 6/300 |
|
|
[考研] 336求調劑 +5 | rmc8866 2026-03-21 | 5/250 |
|