On Thursday, October 29, 2015 at 1:24:23 PM UTC-4, Stefan Karpinski wrote: > > Yes, this is an unfortunate consequence of mathematics being column-major > – oh how I wish it weren't so. The storage order is actually largely > irrelevant, the whole issue stems from the fact that the element in the ith > row and the jth column of a matrix is indexes as A[i,j]. If it were A[j,i] > then these would agree (and many things would be simpler). I like your > explanation of "an index closer to the expression to be evaluated runs > faster" – that's a really good way to remember/explain it. > > To help understand, is "math being column major" referring to matrix operations in math textbooks are done by columns? For example:
http://eli.thegreenplace.net/2015/visualizing-matrix-multiplication-as-a-linear-combination/ While the order is by convention (eg not that is has to be that way), this is how people are taught. Glen
