Talking about weird math symbols...
Community Forums/General Help/Talking about weird math symbols...
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| Well Nate was, and now I am too. I'm familiar with the symbol for the magnitude of a vector, which is a vertical line either side of the vector. I'm seeing some math now which uses two vertical lines each side (for a total of four) of the vector. I'm not sure if it's just an alternate representation for the length of a vector or if it's something else completely. I know the symbols for the dot and cross products, and I can't think of anything else offhand. It looks like it's a scalar value anyway, which would discount the cross product. |
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| Two vertical lines on both sides represents a normalized vector. |
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| I would think the double lines just mean magnitude unless the author specifies that they mean something else. The traditional convention is that single lines are used for numbers and mean "absolute value". The double lines are for vectors and mean "magnitude". Note that they mean the same thing in the case of one-dimensional vectors. They both mean the size of something, whether number or vector. |
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| I agree with Floyd, regarding AndrewT's post - a unit vector (normalised) has a little ^ hat above it usually, as far as I know, not vertical lines on either side of the vector. ||a|| - magnitude, ~ ^ a - normalised / unit vector (admittedly it's difficult to draw these in a forum post...) ~ |
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| Everybody is right! Everybody is also a tiny bit wrong! Double lines represents a 'norm' operation, but it may or may not be the usual one (Euclidean magnitude of the vector). A norm is an operation which assigns a real-number 'size' to a vector or matrix, obeying some simple rules. The Euclidean length function (in any number of dimensions, so this applies to real numbers as well as vectors) is usually represented by single lines, so if you see double lines there's probably a different norm being used, or whatever expression you're looking at applies to any normed space. |
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| I've finished implementing the math now and it looks as though on this occasion it was indeed the vector magnitude operation which was being indicated. Thanks for all the explanations. |
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| Yeah I think it's magnitude, at least I have always understood it to be the "abosulte" value, which is the saame thing really ) |
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