how to create this matrix?
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can anyone help me to construct this matrix
blj=(-2)^j-l if l<j
blj=1 if l=j
blj=0 if l>j
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采纳的回答
Brian Hart
2018-12-22
编辑:Brian Hart
2018-12-22
Hi diadalina,
I think it would look something like this...
iLength = 5; %rows
jLength = 7; %cols
b=zeros(iLength, jLength);
for i = 1:iLength
for j = 1:jLength
if i == j; b(i,j) = 1; end
if i < j; b(i,j) = (-2)^(j-i); end
end
end
disp(b)
gives a result of:
1 -2 4 -8 16 -32 64
0 1 -2 4 -8 16 -32
0 0 1 -2 4 -8 16
0 0 0 1 -2 4 -8
0 0 0 0 1 -2 4
2 个评论
Guillaume
2018-12-22
It is unclear if the formula in the question is
as written or
which would make more sense. One thing for sure, it's not likely to be
which is what you calculate.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/199633/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/199634/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/199635/image.png)
更多回答(2 个)
Guillaume
2018-12-22
编辑:Guillaume
2018-12-22
Assume your formula is
and not what you have written:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/199636/image.png)
nrows = 5; %number of rows. You haven't specified
ncols = 7; %number of columns. You haven't specified
b = toeplitz([1, zeros(1, nrows-1)], (-2).^(0:ncols-1))
If the formula is what you have actually written,
, then
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/199637/image.png)
b = triu((-2).^(1:ncols) - (1:nrows)', 1) + eye(nrows, ncols)
Stephan
2018-12-22
编辑:Stephan
2018-12-22
Hi,
do you want a square matrix? Is the calculation correct without any brackets? My calculation follows the way you wrote the formula - if wrong set the brackets corresponding to your expected result.
Then try:
k=3;
[m,n]=meshgrid(1:k);
A=triu((-2).^n-m,1) + eye(k)
Best regards
Stephan
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