[问题] 循环问题

楼主: willreturn ( )   2014-12-07 15:41:01
我现在在试着用Mathematica写一个FDTD的算法
希望可以画出电磁波的传递动画
但是在跑的时候一直出现错误讯息
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])]
错误讯息是
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. \
\!\(\*ButtonBox[\">>\",
Appearance->{Automatic, None},
BaseStyle->\"Link\",
ButtonData:>\"paclet:ref/message/General/write\",
ButtonNote->\"Set::write\"]\)"
但是我实在找不到我哪边有误用Set(=)了,
有人可以帮我解惑一下吗?
作者: LPH66 (-6.2598534e+18f)   2014-12-07 15:52:00
你中间有一个 Ex[kk] 不是双中括号, 改掉试试?(倒数第二行)啊, 我找到了.... Ex[[ks]] 前面没有分号
楼主: willreturn ( )   2014-12-07 16:02:00
喔喔 太感谢了!!!
作者: ntust661 (TOEFL_5!)   2014-12-09 16:26:00
推推XD

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