Re: [boost] boost.numeric (and multi_array)

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2001-03-25 22:49:15

Too bad we can't overload operator,() for integers. There is no way we can
write A[1,2,3]. Though, we may be able to get something close to it...

On Sun, 25 Mar 2001, Doug Gregor wrote:
gregod> 
gregod> A[1 <= stride(1) < 2, 2 <= stride(2) <= 8]
gregod> 
gregod> Specifying intervals using function notation is unfortunate in C++ because 
gregod> the use of parentheses or brackets doesn't match the mathematical notation. 
gregod> The range (a, b) expressed mathematically is unambiguous, but if we have a 
gregod> C++ functoin call interval(a, b) the user will always be sent back to the 
gregod> documentation to figure out what happens at the endpoints. Using relational 
gregod> operators it is unambiguous.
gregod> 
gregod> While I'm throwing out random syntax, an interface between the lambda library 
gregod> and the multidim array/matrix/linear algebra library could allow for some 
gregod> really nice code:
gregod> 
gregod> // A is M x N, B is N x R
gregod> indexer<int> i, j, k;
gregod> C[i, j] = sum(A[i, k] * B[k, j], for_all(0 <= k < N)), 
gregod> 	for_all(0 <= i < M, 0 <= j < R);
gregod> 
gregod> And for a really neat trick, have the library tile this loop nest :)
gregod> 
gregod> 	Doug
gregod> 
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gregod> 
gregod> 
gregod> 

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 Jeremy Siek                        www: http://www.lsc.nd.edu/~jsiek/
 Ph.D. Candidate                  email: jsiek_at_[hidden]
 Univ. of Notre Dame         work phone: [phone]
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