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matlab中求多元函数的梯度（编转）

2011-03-16 20:12:22| 分类： matlab | 标签： |举报 |字号大中小订阅

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若某一函数f(x)是一个n元函数，x是一个向量，如何求该函数的梯度？

举个例子  syms x y z  f=x^2+x*y+z;  gradient=jacobian(f,[x,y,z])%求梯度   %gradient =   %[ 2*x + y, x, 1]  x=-1;y=2;z=3;  tiduzhi=eval(gradient) %求在（-1，2，3）的梯度值  %  %tiduzhi =  %  %     0    -1     1

对于没有给出具体表达式的函数f(x)

直接用diff求微分  gradient=[diff(f,x),diff(f,y),diff(f,z)]

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