[問題] 迴圈問題

看板Mathematica作者willreturn ( )時間10年前 (2014/12/07 15:41)推噓3(3推 0噓 1→)

留言4則, 3人參與討論串1/1

我現在在試著用Mathematica寫一個FDTD的演算法希望可以畫出電磁波的傳遞動畫但是在跑的時候一直出現錯誤訊息 ke = 100; nsteps = 100; ks = ke/2; c0 = 3 10^8; Ex = Table[0, {i, 0, ke}]; Hy = Table[0, {i, 0, ke}]; dx = 0.01; dt = dx/(2 c0); cc = c0 dt/dx; t0 = 20; sp = 8; plotex = ListPlot[Ex]; Dynamic[plotex] For[t = 1, t <= nsteps, t++, (For[kk = 2, kk <= ke - 1, kk++, Ex[[kk]] = Ex[[kk]] + cc (Hy[[kk - 1]] - Hy[[kk]]); ] Ex[[ks]] = Exp[-0.5*(t - t0)^2/sp^2]; For[kk = 1, kk <= ke - 1, kk++, Hy[[kk]] = Hy[[kk]] + cc (Ex[kk] - Ex[[kk + 1]])]; ListPlot[Ex])] 錯誤訊息是 Set::write : "Tag Times in 0.\ Null is Protected. " "Tag Times in Null\ (0. +0.5\ (0.5\ (0. \ +{0,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,\ 0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,0.,\ 0.,0.,0.,0.,<<51>>}[49])-0.5\ (0. \ +{0,0.,0.,<<45>>,0.,0.,<<51>>}[50]))) is Protected. \ \!\(\*ButtonBox[\">>\", Appearance->{Automatic, None}, BaseStyle->\"Link\", ButtonData:>\"paclet:ref/message/General/write\", ButtonNote->\"Set::write\"]\)" 但是我實在找不到我哪邊有誤用Set(=)了，有人可以幫我解惑一下嗎? -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 118.166.245.251 ※ 文章網址: http://www.ptt.cc/bbs/Mathematica/M.1417938063.A.B47.html