An easy way to modify matrix elements?
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I've created a matrix, P, representing products (the rows set by NCE = 1:NCEMAX) over time (20 years - columns). I launch 1 product/year, some of which will fails 4 years into production (randomly 3x1 matrix). It might look like this without failure (a 1 represents in manufacture)
NCEMAX = 3;
P=[...
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1]
Failure = [1;0;1]
The matrix I want to create would be, as the second product fails 4 years after it starts (ie year 5 as it is NCE2)
NCE2 = [...
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1]
I've tried
P(: , NCE+4:end) = P(: , NCE+4:end) .* Failure;
but the NCE+4 doesn't shift up each row, i.e. NCE+4 always = 5 not 5,6 then 7.
What am I doing wrong? Any help much appreciated.
4 个评论
Torsten
2021-12-24
Please include your executable code.
Stephen23
2021-12-24
NCE is a vector. Adding 4 to NCE returns another vector. Using a vector as any input to the colon operator ignores all elements of the vector except the first element, as documented here:
" If you specify nonscalar arrays, then MATLAB interprets j:i:k as j(1):i(1):k(1)."
That explains the behavior you observe. It is not clear from your question what you expect to happen.
Image Analyst
2021-12-24
编辑：Image Analyst
2021-12-24
What does Failure represent? Like if it is 1 then that row fails for years 4 and later so P for that row would be 1 for columns 1,2 and 3, then 1 for 4-20?
What exactly is supposed to be shifting upwards? Some rows get shifted up, like row 3 moves into row 2 or something?????
So P=1 for no failure and P=0 for failure? And what value indicates failure in the failure vector 1 or 0?
Why does the first column and second of NCE2 have some zeros in some rows before the 1's start? Is that because the product has not yet been produced for those years?
Andrew Rutter
2021-12-25
采纳的回答
Perhaps this:
NCEMAX = 3;
P = ones(NCEMAX, 20);
Failure = [1;0;1];
[rows, columns] = size(P);
NCE2 = zeros(rows, columns);
for row = 1 : rows % For each year.
NCE2(row, row:end) = 1; % Initialize to no failure
if Failure(row) == 0
% Failed at year 4 after introduction
NCE2(row, row+4:end) = 0;
end
end
NCE2 % Show in command window.
更多回答（1 个）
for NCE = 1:NCEMAX
if Failure(NCE) == 0
P(NCE,NCE+4:end) = 0
end if
end
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