How can I perform vector calculations in lisp, such as magnitude of a vector, norm of a vector, distance (between two points), dot product, cross product, etc.
Thanks.
+4
A:
There are several libraries of bindings to Fortran linear algebra packages like LAPACK and BLAS, such as LLA, the Lisp Linear Algebra library.
Charles Stewart
2010-05-26 12:14:17
+1
A:
All this stuff is incredibly straight-forward maths. Calculate it the way you would normally.
Noon Silk
2010-05-26 12:15:39
...if you don't care about performance.
Charles Stewart
2010-05-26 12:27:29
@Charles So what is the more performant way of doing a dot product? Because that's simple multiplying two numbers together. And cross product is only slightly more complicated than that. And magnitude of a vector, well, again it's a very trivial operation. Exactly what speed benefits are you implying the existence of?
Noon Silk
2010-05-26 12:37:24
What's the order of an N-dimensional cross-product? It's more than "Slightly more complicated". Applications of linear algebra tend to be of large dimension.
Charles Stewart
2010-05-26 13:59:14
@Silky: the more performant way of doing a dot product is the one that compiles down to the most efficient code. Even though the same mathematical operations are being performed, two implementations of a dot product can easily differ by an order of magnitude or more in execution time.
Stephen Canon
2010-05-26 14:36:22
@Charles: Fair enough, @Stephen: That's an incredibly useless comment.
Noon Silk
2010-05-26 22:46:10