谢谢MATLAB 指令窗中的help指令和lookfor指令
s+<`iH9Hm 作者：精通MATLAB(5.3版) 来源：转载
http://www.51base.com/machine/softedu/cam/matlab/5120060126150.shtml 发布时间：2008-4-16 9:29:54
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OPuty/^!Gw +mRc8 G 2.9.2 指令窗中的 help 指令
SH6+'7 %7hf6Xo= 2.9.2.1 直接使用 help 获得指令的使用说明
V\nj7Gr:sF ) #l&BV5 【例 2.9.2 .1-1 】假如准确知道所要求助的主题词，或指令名称，那末使用 help 是获得在线帮助的最简单有效的途径。本例演示：关于矩阵对数函数 logm 使用说明的在线求助。
k?;@5r) y- x8!uI)#tS help logm
{\vcwMUzZ LOGM Matrix logarithm.
VOSq%hB L = LOGM(A) is the matrix logarithm of A, the inverse of EXPM(A). Complex results are produced if A has negative eigenvalues. A warning message is printed if the computed expm(L) is not close to A.
R ~"&E#C zQ#2BOx1 [L,esterr] = logm(A) does not print any warning message, but returns an estimate of the relative residual,norm(expm(L)-A)/norm(A).
}eAV 8LU qM18 Ji* If A is real symmetric or complex Hermitian, then so is LOGM(A).
Oq*;G R(Q $1y8X K7r Some matrices, like A = [0 1; 0 0], do not have any logarithms, real or complex, and LOGM cannot be expected to produce one.
n{I1ZlEeh F4 ]=(T See also EXPM, SQRTM, FUNM.
7g>|e DX_?-jw})f 2.9.2.2 使用 help 指令进行分类搜索
{X10, 4MrUo9L$s 【例 2.9.2 .2-1 】运行不带任何限定的 help ，可以得到分类名称明细表。
4^Og9}bm N4l} 5(e help
i ?%_P u HELP topics:
z&Xk~R*$ matlab\general - General purpose commands.
Vg(FF " matlab\ops - Operators and special characters.
4rLc]
> matlab\lang - Programming language constructs.
WD@v<Wx) matlab\elmat - Elementary matrices and matrix manipulation.
WK5B8u*< matlab\elfun - Elementary math functions.
VG_xNM matlab\specfun - Specialized math functions.
0Ibe~!EiQJ ...... ......
Ri Z)#0 For more help on directory/topic, type "help topic".
! u;gGgQF vN Hvuw K 2.9.2.3 采用 help topic 指令形式获得具体子类的指令明细
wb>"'% XS$#\UQ 【例 2.9.2 .3-1 】如果用户想知道有关矩阵操作指令一栏表，那末就运行以下指令。
hkOFPt& cB)tf S4) help elmat
qpjiQ,\ :b Elementary matrices and matrix manipulation.
8g {;o 7 Elementary matrices.
Ept =&mJPu zeros - Zeros array.
cTQ ._|M ones - Ones array.
|AXV4{j_i ...... ......
- "EPU]q W fHa Basic array information.
`>GXJ~:D[" size - Size of matrix.
|\xTcS|d length - Length of vector.
U|<>xe*|% ...... ......
F:sUGM, D&x.io Matrix manipulation.
Yx&d\/ 9 reshape - Change size.
" xNP"S diag - Diagonal matrices and diagonals of matrix.
N2 t` ...... ......
22*~CIh~x 'w=aLu5dY Special variables and constants.
u2IU/z8
^ ans - Most recent answer.
@{Dfro eps - Floating point relative accuracy.
Tb!F O"o ...... ......
?zf3AZ9 x`Wb 9[u8 Specialized matrices.
]Ot= At compan - Companion matrix.
9fWR8iV gallery - Higham test matrices.
jZH4]^De ...... ......
'#>F e`[ >[&ser 〖说明〗省略号由笔者所加，用来表示被删除的内容。这样做是出于节省篇幅的考虑。
$wyPGok $3g M P+ x |gYxZ 2.9.3 指令窗中的 lookfor 指令
\}\#
fg A ]1dR\p 【例 2.9.3 -1 】查找包含积分这个关键词的所有指令。
O0s,)8+z5D FAdTp.
lookfor integral
Xpv<v[a ELLIPKE Complete elliptic integral.
4 9HP 2E EXPINT Exponential integral function.
omznSL DBLQUAD Numerically evaluate double integral.
v2a(yH INNERLP Used with DBLQUAD to evaluate inner loop of integral.
?a*w6,y. QUAD Numerically evaluate integral, low order method.
;mg.} fI QUAD8 Numerically evaluate integral, higher order method.
s IBP$9 COSINT Cosine integral function.
%zo
6A1Q; SININT Sine integral function.
O.Y|},F ASSEMA Assembles area integral contributions in a PDE problem.
;$8ptB . COSINT Cosine integral function.
S y]W4% FOURIER Fourier integral transform.
fqBz"l>5A IFOURIER Inverse Fourier integral transform.
x iz+ R9p SININT Sine integral function.
