sys-cluster/lwgrp: initial import

Signed-off-by: Alessandro Barbieri <lssndrbarbieri@gmail.com>

sys-cluster/lwgrp/Manifest

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+DIST lwgrp-1.0.3.tar.gz 39217 BLAKE2B 2e17fce02989832670a7bcd73f80e3aabe185b5d1120777f3d3d2e0bd630e62b6ae64638b724ca3edd9d9c7d7177e505433c16382b5e1fdbc79e8a1b1de1a622 SHA512 b8acdd5fcec8de01f80acfe0f6df33fe3281bd6465a33ad739af06189782f116ac32caacbd458d2e04ba2eaedfbebf67f42cc343f7bee43f8d708e2b8b3c1565

sys-cluster/lwgrp/lwgrp-1.0.3.ebuild

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+# Copyright 2019-2021 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit autotools
+
+DESCRIPTION="Light-weight Group Library"
+HOMEPAGE="https://github.com/LLNL/lwgrp"
+SRC_URI="https://github.com/LLNL/lwgrp/archive/refs/tags/v${PV}.tar.gz -> ${P}.tar.gz"
+
+LICENSE="BSD"
+SLOT="0"
+KEYWORDS="~amd64"
+IUSE="mpianysource"
+
+RDEPEND="virtual/mpi"
+DEPEND="${RDEPEND}"
+
+src_prepare() {
+	default
+	eautoreconf
+}
+
+src_configure() {
+	local myconf=(
+		$(use_enable mpianysource)
+	)
+	econf "${myconf[@]}"
+}
+
+src_install() {
+	default
+	rm -r "${ED}/usr/share/${PN}" || die
+	find "${ED}" -name '*.la' -delete || die
+	find "${ED}" -name '*.a' -delete || die
+}

sys-cluster/lwgrp/metadata.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="person">
+		<email>lssndrbarbieri@gmail.com</email>
+		<name>Alessandro Barbieri</name>
+	</maintainer>
+	<longdescription lang="en">
+The light-weight group library defines data structures and collective
+operations to group MPI processes as an ordered set.  Such groups are
+useful as substitutes for MPI communicators when the overhead of
+communicator creation is too costly.  For example, certain sorting
+algorithms recursively divide processes into subgroups as the sort
+algorithm progresses.  These groups may be different with each
+invocation, so that it is inefficient to create and destroy
+communicators during the sort routine.
+
+Data structures:
+chain    - each member records addresses of left and right members first and last rank set boundary to MPI_PROC_NULL
+ring     - like the chain, except first and last rank wrap around 
+logchain - each member records addresses of each member 2^d hops to left and right d=0..log(N)-1 (MPI_PROC_NULL at ends)
+logring  - each member records addresses of each member 2^d hops to left and right with wrap at ends
+
+We represent groups of processes using a doubly-linked list called
+a "chain".  This is a very simple struct that records the number
+of processes in the group, the rank of the local process within the
+group, the address of the local process, and the addresses of the
+processes having ranks one less (left) and one more (right) than the
+local process.  We implement the LWGRP library on top of MPI, so for
+addresses we record a parent communicator and ranks within that
+communicator.  To be light-weight, the reference to the communicator
+is a literal copy of the handle value, not a full dup.
+
+Since each member only stores the addresses for a few other group
+members, it is the responsibility of higher level software to exchange
+address information for more general point-to-point communication.
+Additionally, the caller is responsible for choosing tag values as a
+group context.
+
+There is also a "ring", which is like a chain, but it wraps around
+at the ends.
+
+There are two structures, called a logchain and logring, used to cache
+adddresses of more group members.  These structures must be used in
+conjunction with either a chain or ring, respectively.  They cache
+addresses for processes that are 2^d hops to the left and right sides
+where d ranges from 0 to log(N)-1 inclusive.  This pattern enables
+one to construct trees, and so it's useful to cache this information
+for use in collective operations.
+	</longdescription>
+	<use>
+		<flag name="mpianysource">Specify whether to use MPI_ANY_SOURCE</flag>
+	</use>
+	<upstream>
+		<bugs-to>https://github.com/LLNL/lwgrp/issues</bugs-to>
+		<remote-id type="github">LLNL/lwgrp</remote-id>
+	</upstream>
+</pkgmetadata>