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Joined: 28/08/2014(UTC) Posts: 1,359 Was thanked: 818 time(s) in 518 post(s)
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Hi. I guess that not a bug, nor doing something wrong. What I see it's a parenthesis problem. With yours last two approximations what you get is that SMath evaluates first col function, then matrix product. But in the first example, and as you can see in the symbolic evaluation, what SMath do is first the matrix product, then try to get the col. So, the problem it's about that there are not an obvious way except both that you use, for change the operation order, i.e. a parenthesis question. Best regards. Alvaro.
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Joined: 23/07/2013(UTC) Posts: 1,128 Was thanked: 509 time(s) in 339 post(s)
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Well, using submatrices has solved the problem. You can be right, it seems col() is calculated after matrix. But I don't think it is related to paranthesis. I have tried nearly every possible usage way of parantheses with col() function, no success so far If submatrices have no problem with same usage, then somehow this must be related col(). Regards
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Originally Posted by: overlord Is this a bug or am I doing something wrong? Just wrongdoing ... doctored. vectorize_or_col.sm (15kb) downloaded 18 time(s).
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Joined: 23/07/2013(UTC) Posts: 1,128 Was thanked: 509 time(s) in 339 post(s)
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Well Jean,
Thank you for your reply. But this is how I had done this calculation previously, for years. I don't want to do it like this. I am trying to calculate it via vectorize. It looks more elegant on the paper. Which I did by the way, you can see the picture above.
Regards
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Rank: Guest
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Joined: 04/07/2015(UTC) Posts: 6,866 Was thanked: 981 time(s) in 809 post(s)
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Originally Posted by: overlord Thank you for your reply. But this is how I had done this calculation previously, for years. I don't want to do it like this. I am trying to calculate it via vectorize. It looks more elegant on the paper. Which I did by the way, you can see the picture above. ... then add more elegance and space saving, backward compatible.
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Rank: Advanced Member Groups: Registered
Joined: 23/07/2013(UTC) Posts: 1,128 Was thanked: 509 time(s) in 339 post(s)
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Well, I used to do that too It is at the end of smath file by the way. I will stick with submatrix and vectorize method. It is the most space saving method I could think of. Thanks and regards
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Joined: 04/07/2015(UTC) Posts: 6,866 Was thanked: 981 time(s) in 809 post(s)
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Originally Posted by: overlord I will stick with submatrix and vectorize method. It is the most space saving method I could think of. ... even more compact/elegant
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Rank: Advanced Member Groups: Registered
Joined: 28/08/2014(UTC) Posts: 1,359 Was thanked: 818 time(s) in 518 post(s)
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Originally Posted by: overlord Well, using submatrices has solved the problem. You can be right, it seems col() is calculated after matrix. But I don't think it is related to paranthesis. I have tried nearly every possible usage way of parantheses with col() function, no success so far If submatrices have no problem with same usage, then somehow this must be related col(). Regards Hi Overlord. Yes, you're right, the new range access to submatrices method is the more elegant solution, this is the more readable, and math are a lot of things, but for sure is a thing of how can one visualize the problems. If math's notation isn't clear, it can introduce mistakes in their applications. When I talk about parentheses is about that it is the usual tool for change the evaluation order in an expression, and isn't clear how to do that under the vectorize() function. For some reason col() isn't evaluated first than product, but range matrix access it is. Best regards. Alvaro.
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