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Basic vector functions in Sage

asked 2012-04-25 00:43:34 -0500

paldepind gravatar image

updated 2015-01-14 04:00:17 -0500

FrédéricC gravatar image

Isn't there any inbuilt 3D vector functions in Sage?

For instance like a function to get the dot product, cross product or angle between two vectors? Or functions to get the distance from a point to a line? Find the intersections between two lines? Having such functions would be a great help and would greatly increase the speed of my workflow in school.

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answered 2012-04-25 06:08:39 -0500

kcrisman gravatar image

These are all accessible using the "dot" object-oriented notation. See, for example, this documentation, from which this example stems.

sage: v = vector([1,2,3]); w = vector([0,5,-9])
sage: v.cross_product(v)
(0, 0, 0)
sage: u = v.cross_product(w); u
(-33, 9, 5)
sage: u.dot_product(v)
0
sage: u.dot_product(w)
0
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I only see cross product and dot product? What about the other things I mentioned? And for instance the distance from a point to a plane? I can't find any of it by searching.

paldepind gravatar imagepaldepind ( 2012-05-01 06:03:47 -0500 )edit

I don't think that Sage would include things that one is supposed to do mathematics for. The intersection of two lines would depend greatly on how you represented them, for instance - parametric, as an intersection of planes, as a formula in 2D... Same thing with an angle, which you can get from the cross *or* dot product with inverse trig functions. Of course, many of these would be relatively easy to implement, and we would welcome the addition.

kcrisman gravatar imagekcrisman ( 2012-05-01 15:36:21 -0500 )edit

Thanks for the explanation. How can I implement these functions in Sage? At least for my own usage.

paldepind gravatar imagepaldepind ( 2012-05-02 22:42:27 -0500 )edit

Depends on what you want. For your own usage, you could put the code for such a thing in a .sage file and then have loading that file done automatically by an init.sage file (search for this). For wider distribution, see http://www.sagemath.org/doc/developer/walk_through.html for how to start contributing to Sage directly, or you could just upload code for an algorithm to a ticket you created on http://trac.sagemath.org/sage_trac/.

kcrisman gravatar imagekcrisman ( 2012-05-03 03:36:22 -0500 )edit

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Asked: 2012-04-25 00:43:34 -0500

Seen: 7,220 times

Last updated: Apr 25 '12