How to expand a row of values into a matrix, such that each new value is equal to the value above it plus one?

Question

Marco 2024-6-27，16:57

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https://ww2.mathworks.cn/matlabcentral/answers/2132616-how-to-expand-a-row-of-values-into-a-matrix-such-that-each-new-value-is-equal-to-the-value-above-it

回答： Umar 2024-6-27，17:03

What I'm asking for is a lot simpler to show than to explain. If I have a vector such as, for example:

[5 10 15]
ans = 1x3
     5    10    15
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How can I expand the vector for any integer length n (for this example let's say n=3) into a matrix such that:

[5 10 15; 6 11 16; 7 12 17]
ans = 3x3
     5    10    15
     6    11    16
     7    12    17
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I know there's a brute force solution with for-loops, but I'm trying to avoid for-loops where I can and stick to vectorization for efficiency. Is there anything I can use?

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Answer 1

Voss 2024-6-27，17:02

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在 MATLAB Online 中打开

v = [5 10 15];
n = 3;
m = v+(0:n-1).'
m = 3x3
     5    10    15
     6    11    16
     7    12    17
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>

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Answer 2

Umar 2024-6-27，17:03

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2132616-how-to-expand-a-row-of-values-into-a-matrix-such-that-each-new-value-is-equal-to-the-value-above-it#answer_1478046

Hi Marco,

By using bsxfun with element-wise addition and transpose to adjust dimensions, you can efficiently expand the vector into a matrix without resorting to for-loops, ensuring a more vectorized and optimized solution.

For more information regarding bsxfun, please refer to

https://www.mathworks.com/help/matlab/ref/bsxfun.html

Hope that answers your question.