Syntax x = fmin('fun',x1,x2)

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work wolf 2016-8-31

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/301429-syntax-x-fmin-fun-x1-x2

评论： Star Strider 2016-9-1

采纳的回答： Star Strider

在 MATLAB Online 中打开

Syntax

      x = fmin('fun',x1,x2)
      x = fmin('fun',x1,x2,options)
      x = fmin('fun',x1,x2,options,P1,P2, ...)
      [x,options] = fmin(...)

are not working by matlab? the message from matlab as follows as:

>> f =@(x) x.^3-2*x-5;
>> x = fmin('f', 0, 2)
Undefined function 'fmin' for input arguments of type 'char'.

Did you mean:

>> x = min('f', 0, 2)
Error using min
MIN with two matrices to compare and a working dimension is not supported.
>> x = fminbnd('f', 0, 2)
Cannot find an exact (case-sensitive) match for 'f'

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采纳的回答

Star Strider 2016-8-31

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/301429-syntax-x-fmin-fun-x1-x2#answer_233205

在 MATLAB Online 中打开

You’re almost there.

This works:

f =@(x) x.^3-2*x-5;
x = fminbnd(f, 0, 2)
x =
   816.4968e-003

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work wolf 2016-9-1

Relly , thank you sooooo much

Star Strider 2016-9-1

As always, my pleasure!

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Walter Roberson 2016-8-31

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/301429-syntax-x-fmin-fun-x1-x2#answer_233208

在 MATLAB Online 中打开

http://www.mathworks.com/help/releases/R13sp2/techdoc/ref/fmin.html

"Note: The fmin function was replaced by fminbnd in Release 11 (MATLAB 5.3). In Release 12 (MATLAB 6.0), fmin displays a warning message and calls fminbnd."

If you are using MATLAB 5.3 or earlier, that is important information for us to know. If you are using something that old, you would use

x = fmin('f', 0, 2)

but you would also have to have created file f.m with content

function y = f(x)
  y = x.^3-2*x-5;

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work wolf 2016-8-31

在 MATLAB Online 中打开

 x = fmins('fun',x0) 
x = fmins('fun',x0,options) 
x = fmins('fun',x0,options,[],P1,P2, ...) 
[x,options] = fmins(...)
and 
z = fzero('fun',x) z = fzero('fun',x,tol) 
z = fzero('fun',x,tol,trace) 
z = fzero('fun',x,tol,trace,P1,P2,...)