Introduction

This is a user's guide for the C++ binding for the QDP Data Parallel Applications Programmer Interface developed under the auspices of the U.S. Department of Energy Scientific Discovery through Advanced Computing (SciDAC) program.

The QDP Level 2 API has the following features:

• Provides data parallel operations (logically SIMD) on all sites across the lattice or subsets of these sites.
• Operates on lattice objects, which have an implementation-dependent data layout that is not visible above this API.
• Hides details of how the implementation maps onto a given architecture, namely how the logical problem grid (i.e. lattice) is mapped onto the machine architecture.
• Allows asynchronous (non-blocking) shifts of lattice level objects over any permutation map of sites onto sites. However, from the user's view these instructions appear blocking and in fact may be so in some implementation.
• Provides broadcast operations (filling a lattice quantity from a scalar value(s)), global reduction operations, and lattice-wide operations on various data-type primitives, such as matrices, vectors, and tensor products of matrices (propagators).
• Operator syntax that support complex expression constructions.

Disclaimer

No claim is made as to the completeness of this User Guide. While every attempt has been made to present information accurately, all of the wording is subject to revision, and suggestions for improvements, corrections or additions will be gratefully received.