From: Martin Schulz (Martin.Schulz_at_[hidden])
Date: 2007-07-02 02:53:59
Hello,
that seems promising to me. Can I download that library somewhere on the
net to have a closer look at it?
I have to apologize that I probably wont find much time really soon,
though. At least I would like to get a better idea of it.
Yours,
Martin.
--
Dr. Martin Schulz (schulz_at_[hidden])
Software Engineer
Synopsys GmbH
Karl-Hammerschmidt-Str. 34
D-85609 Dornach, Germany
Phone: +49 (89) 993-20203
http://www.synopsys.com
> -----Original Message-----
> From: boost-bounces_at_[hidden]
> [mailto:boost-bounces_at_[hidden]] On Behalf Of Jeremy Bruestle
> Sent: Freitag, 29. Juni 2007 22:10
> To: boost_at_[hidden]
> Subject: [boost] Interest in tensor library?
>
> Greetings,
>
> I have developed a C++ tensor library using template
> expressions which allows Einstein summation convention to be
> used to describe mathematical operations on tensors in C++.
> This allows a great simplification in syntax, while retaining
> execution speeds identical to hand optimized C code in most
> cases. An example of the syntax is:
>
> // Declare three rank 2 tensors (rank = # of dimensions) of
> doubles with sizes of // 6 x 5, 6 x 10, and 10 x 5 respectively
>
> tensor<double, 2> A(6, 5);
> tensor<double, 2> B(6, 10);
> tensor<double, 2> C(10, 5);
>
> // Name three index variable to be used in what follows
> index_variable<0> i; index_variable<1> j; index_variable<2> k;
>
> A[i][j] = 1.0; // Initialize A to all 1's B[i][j] = 4.5; //
> Initalize B to all 4.5
>
> boost::mt19937 rng;
> C[i][j] = trand(rng); // Initalize C to uniform random
> numbers 0-1 C[i][2] = 2.1; // Set row 2 to 2.1 C[2][i] =
> 5.5; // Set col 2 to 5.5 C[2][2] = 0.0; // Zero out 2,2
>
> A[i][j] = B[i][k] * C[k][j]; // Perform a matrix multiply
>
> /* The above line translates roughly as:
> for(size_t i = 0; i < A.size<0>(); i++)
> {
> for(size_t j = 0; j < A.size<1>(); j++)
> {
> double total = 0.0;
> for(size_t k = 0; k < B.size<1>(); k++)
> total += B[i][k] * C[k][j];
> A[i][j] = total;
> }
> }
> */
> An unlimited number of dimensions are supported, arbitrary
> operations are allowed, and for cases where you wish to
> perform other types of cumulative functions, such as finding
> the maximum element, a syntax such as: A[i] = max(j,
> B[i][j]); is allowed. There are lots of other interesting
> features but I don't wish to make this email too long.
>
> As far as efficency, Intel's compiler builds every example
> I've tried so far into code as good as doing the work by
> hand. GCC does so for expressions of reasonably complexity,
> and MSVC's optimizer does alright, but not nearly as well as
> the others.
>
> I was interested in knowing what the interest level of
> providing such a library as part of boost would be. I've
> tried to adhere to the boost coding guidelines during the
> construction. I've been using this library for over 6 months
> myself for scientific computing. However, I've so far
> avoiding sending a query to the boost mailing lists as the
> procedures for submission and review seem quite daunting.
> I'm usually crushingly busy, and I'm also especially bad at
> documentation. Still, I thought I would float the idea to
> guage interest, and also ask if anyone would be interested in
> helping me through the process somewhat.
>
> Thank you for you time.
>
> -Jeremy Bruestle
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