作业帮matlab中的feval函数怎么用希望举一个简单的例子
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matlab中的feval函数怎么用希望举一个简单的例子
matlab中的feval函数怎么用
希望举一个简单的例子
matlab中的feval函数怎么用希望举一个简单的例子
feval
Evaluate function
Syntax
[y1,y2,...] = feval(fhandle,x1,...,xn)
[y1,y2,...] = feval(function,x1,...,xn)
Description
[y1,y2,...] = feval(fhandle,x1,...,xn) evaluates the function handle,fhandle,using arguments x1 through xn.If the function handle is bound to more than one built-in or M-file,(that is,it represents a set of overloaded functions),then the data type of the arguments x1 through xn determines which function is dispatched to.
Note It is not necessary to use feval to call a function by means of a function handle.This is explained in Calling a Function Using Its Handle in the MATLAB?Programming Fundamentals documentation.
[y1,y2,...] = feval(function,x1,...,xn).If function is a quoted string containing the name of a function (usually defined by an M-file),then feval(function,x1,...,xn) evaluates that function at the given arguments.The function parameter must be a simple function name; it cannot contain path information.
Remarks
The following two statements are equivalent.
[V,D] = eig(A)
[V,D] = feval(@eig,A)
Examples
The following example passes a function handle,fhandle,in a call to fminbnd.The fhandle argument is a handle to the humps function.
fhandle = @humps;
x = fminbnd(fhandle,0.3,1);
The fminbnd function uses feval to evaluate the function handle that was passed in.
function [xf,fval,exitflag,output] = ...
fminbnd(funfcn,ax,bx,options,varargin)
.
.
.
fx = feval(funfcn,x,varargin{:});
很简单的，feval用来计算指定函数在某点的函数值，如a=feval(fun,x)，就相当于a=fun(x)，如
>>a=feval(@(x)(x^2+1),1)
a =
2
>> a=feval(@(x)(x^2+1),2)
a =
5