清空筛选条件
清空筛选条件

Invalid Index in position 2

2 次查看（过去 30 天）
kevin cecere palazzo
回答： Daniel M 2019-10-4
When I run, Matlab says "Index in position 2 is invalid. Array indices must be positive integers or logical values." I cannot find the error in the following code (ignore that plot function is missing in the end):
clc
clear all
N=50;
M=100;
B=11;
n=50;
s=zeros(N,M);
volat=ones(n,N);
s=zeros(N,M);
rng(11);
figure (1);
hold on
for k=1:N
eps=zeros(n,M);
eps(1,1)=volat(1,k)*randn(1,1);
auxmtx=zeros(M,B,2);
pstar=zeros(M,1);
for i=2:n
if eps(i-1,1)<0
volat(i,1)=0.01+0.89*volat(i-1,1)+0.2*(eps(i-1,1)^2);
else volat(i,j)=0.01+0.89*volat(i-1,1);
end
eps(i,1)=sqrt(volat(i,1))*randn(1,1);
end
s(k,1)=sum(eps(:,1))/sqrt(n);
for j=2:M
for l=1:n
if eps(l,1)>0
eps(l,j)=sqrt(volat(l,1))*abs(randn(1,1));
else
eps(l,j)=eps(l,1);
end
end
s(k,j)=sum(eps(:,j))/sqrt(n);
end
end

请先登录，再回答此问题。

回答（2 个）

Walter Roberson
Walter Roberson 2019-10-4
else volat(i,j)=0.01+0.89*volat(i-1,1);
At that point you have not assigned to j so it is the default sqrt(-1)
Daniel M
Daniel M 2019-10-4
First, rename the variable eps to something else, because you are overloading the built-in Matlab function eps() which is bad practice and could cause problems.
As a prime example of why you shouldn't use Matlab function names as variable names, your Invalid Index error is actually a result of doing this. In the first else statement, you haven't yet defined j, so it is resorting to its default complex value:
clear
j
ans =
0.0000 + 1.0000i

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by