如何在MATLAB中的函数中具有顺序？

编程问答 2022-06-11

问题描述

下面是代码，在没有功能/功能句柄的情况下可以正常工作。但是，我必须编写一个函数，以便可以在MATLAB中使用“ lsqcurvefit”的优化函数并优化参数constant（1）和constant（2）。

L=zeros(n,length(S)); % Height of elements
L(:,1)=Linitial; % Height of elements for day zero
for jj=1:length(S)
   if jj==1
       continue
   end
    for j=1:n % n is 101 (prevIoUsly defined...)
    
     L(j,jj) = @(constant,i_dt) L(j,jj-1) - (i_dt(j,jj).*constant(1).*((L(j,jj-1)./hs)-1)^constant(2)); %*****
     
    end
end

height_pred = @(constant,i_dt) sum(L); %heigh_pred(1) is kNown and prevIoUsly defined
options = optimoptions('lsqcurvefit','FinDiffType','central',...
    'TolFun',1e-10);
constant = lsqcurvefit(height_pred,constant0,i_dt,height_meas,lb,ub,options);

当我运行上述代码时，对于5星（*****）行，我收到错误消息“无法从function_handle转换为两倍”。

如果我删除了函数句柄，而是在我的代码末尾编写了一个函数，如下所示：

L=zeros(n,1)=Linitial; % Height of elements for day zero
for jj=1:length(S)

      for j=1:n % n is 101 (prevIoUsly defined...)
         L(j,jj) = Nelfun(j,jj);
      end
end

height_pred = @(constant,options);

function L = Nelfun(constant,i_dt)
for jj=1:145
   if jj==1
       L(:,1)=0.0187600000000000;
       continue
   end
      for j=1:101
         L(j,jj-1);
         L(j,jj) = L(j,jj-1)./hs)-1)^constant(2)); %*****
      end
end
end

我收到错误消息

"Index exceeds matrix dimensions" for line with (*****).

矩阵i_dt的大小为（101,145），L为（101,145），height_meas（1,145）和height_pred（1,145）。

已知jj == 1的L（j，jj），但应针对L（：，2）至L（：，145）进行计算和优化。

              ***

感谢Praveen，“索引超过矩阵尺寸”的问题已解决，但现在我收到了错误

"Error using snls (line 183)
Finite difference Jacobian at initial point contains Inf or NaN values. lsqcurvefit cannot continue."

以下代码：

lb = [0.000000000001,0.05]; ub = [1,50]; constant0 = [1.06e-09,15.2];

height_pred = @(constant,i_dt) sum(Nelfun(constant,i_dt)); 

options = optimoptions('lsqcurvefit',i_dt)
L=zeros(size(i_dt));
n=101; % number of nodes
ei=2.05613504572765; 
e0=ei.*ones(n,1);
Hsolid=0.613847219422639; 
hs = Hsolid./(n-1);
for JJ=1:size(i_dt,2)
   if JJ==1
     for j=1:n
         Linitial0=hs.*(1+e0);
         Linitial0(1)=0;
     end
     L(:,JJ) = Linitial0;
     continue
   end
     for J=1:size(i_dt,1)
         L(J,JJ) = L(J,JJ-1) - (i_dt(J,JJ).*constant(1).*((L(J,JJ-1)./hs)-1)^constant(2));
     end
end
end

解决方法

在第一种情况下，您无法创建函数句柄数组。您可以使用单元阵列，但我不明白为什么需要它。

让我们来处理第二种情况。

%I don't know what is hs,I assume it a scalar
hs=myhs;
%call the Nelfun in your function handle
height_pred = @(constant,i_dt) Nelfun(constant,i_dt,hs);


options = optimoptions('lsqcurvefit','FinDiffType','central',...
    'TolFun',1e-10);
% Constant0 should be 2 element array
constant0=[0,0];
constant = lsqcurvefit(height_pred,constant0,height_meas,lb,ub,options);

function L = Nelfun(constant,hs)% why hs is not passed
L=zeros(size(i_dt)); % Always initialize before filling it up
for jj=1:size(i_dt,2) %use adaptive indexing
   if jj==1
       L(:,jj)=0.0187600000000000;
       continue
   end
      for j=1:size(i_dt,1) %use adaptive indexing
         L(j,jj) = L(j,jj-1) - (i_dt(j,jj).*constant(1).*((L(j,jj-1)./hs)-1)^constant(2));
      end
   
end
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