R Observatory: Metrics for zuexact version 0.1.0

Balamuta, James Joseph

doi:10.5281/zenodo.21843040

zuexact

0.1.0Package record

Exactly Rounded Sums, Means and Dot Products

0packages depend

48downloads / year

81.7%test coverage

10/10flavors OK

Overview

About

Maintained by Pedro BaltazarCRAN page ↗GitHub ↗Website ↗Issues ↗

Sums of double-precision numbers computed exactly and rounded once, so the result is the correctly rounded true sum and does not depend on the order of the elements, the platform, or whether R was built with long doubles. Built on the small and large superaccumulators of Neal (2015) doi:10.48550/arXiv.1505.05571. Provides exactly rounded sums, means, cumulative sums, dot products and norms, row, column and grouped sums, accumulators that can be built in pieces and merged across processes, and a registered 'C' interface for other packages.

Changes in 0.1.0

First release.

Vendors Radford Neal's 'xsum' (stable version 3), patched so that no standard I/O reaches the compiled code; upstream's checker and fuzzer run against the vendored copy in CI.
A vignette, vignette("exact-summation"), explains why base sum() differs between platforms and how to sum in pieces and from C.
xsum() returns the exactly rounded sum of double, integer, logical and complex vectors, with na.rm, applying the same special-value rules on every platform. ALTREP vectors are read in blocks, never materialised.
zuexact_info() reports the vendored 'xsum' version, the accumulator threshold, SIMD and FMA support, and whether R has long doubles.
xsum_mean() divides the exact sum by the count with one rounding; xsum_weighted_mean() divides two exact sums.

Show all changes in 0.1.0Hide the rest of the changes in 0.1.0

xsum_dot(), xsum_sqnorm() and xsum_norm() include each product's rounding error (TwoProduct with fma()), so dot products are exactly rounded too.
xsum_cumsum() rounds every prefix sum exactly.
Accumulators as R values: xsum_acc(), xsum_add(), xsum_merge(), xsum_negate(), xsum_value() and xsum_mean_value() build exact sums in pieces, in any order, and across processes (they serialise).
xsum_rowsums(), xsum_colsums() and xsum_by() are exact versions of rowSums(), colSums() and rowsum(). Row sums work a block of rows at a time, so their extra memory does not grow with the number of rows.
A registered C interface, zuexact_api_v1 in inst/include/zuexact.h, gives other packages' C code the same exact accumulators, sums, dot products, merges and means, through LinkingTo: zuexact.
Every result is tested against exact rational arithmetic ('gmp'), PreciseSums::fsum(), the test262 Math.sumPrecise vectors and ill-conditioned inputs up to condition number 1e40, and must be bit-identical on every CI platform.

From NEWS.md in the release

Install

R (CRAN)pak (dev)Fedora (COPR)

install.packages("zuexact", repos = "https://cloud.r-project.org/")

Installs the current CRAN release. Prebuilt binaries on Windows and macOS.

if (!requireNamespace("pak", quietly = TRUE))
  install.packages("pak", repos = "https://cloud.r-project.org/")
pak::pak("pedrobtz/zuexact")

Development version from pedrobtz/zuexact. Installs pak first if it is not already available.

# enable the iucar/cran COPR if it is not already present, then install
ls /etc/yum.repos.d/*iucar*cran*.repo >/dev/null 2>&1 \
  || sudo dnf copr enable -y iucar/cran
sudo dnf install -y R-CRAN-zuexact

RPMs from the iucar/cran COPR, rebuilt from CRAN.

For install.packages() integration in R, also: sudo dnf install R-CoprManager

Health

CRAN checks

10OK

CRAN check page ↗

Slowest check: 2.6 min · r-devel-windows-x86_64

Status changes

OK10 OKNow
OK6 OK2026-10-23

Advisories

none known

How this is measured·How advisories are found

Documentation

In release 0.1.0

READMEYes · 275 wordsVignettesYes · 1 · dynamicNEWSYes · 67% structured · mentions 0.1.0Citation fileNoWebsiteYes

Help pages: 9 (1 internal)includes a package overview page
Examples that run: 100%8 run in a plain check
Exported functions with examples: 100%
Documented parameters: 80%
Return-value docs: 100%
Help pages citing references: 0%

Vignettes (1)

Exact summation HTML

How these are measured

Downloads

48

CRAN downloads in the past year

Rank #25,683 · ~0/day · ~4/mo

zuexact Releases R versions

Daily download trend is not available in this view yet.

4830 days

4890 days

481 year

Compare downloads with other packages →

How downloads are counted

Repository

pedrobtz/zuexact ↗Account: pedrobtz

0Stars

0Forks

2Open issues

0Open PRs

1Releases

46Commits

1Commit identities

46 commits · Last activity 2026-10-22

Responsiveness

How these are sampled

PRs merged (all time): 100%
Median days to close, 50 most recently updated closed issues: 0
Median days to close, 50 most recently updated closed PRs: 0

How these are measured

PracticesBeta

Repository github.com/pedrobtz/zuexact is linked, but repository-practices checks have not run for it yet.

How this is detected·Detection ruleset v4 (2026-10-20)

Dependencies

Declared dependencies

6 external dependencies (excludes base and recommended)

Installing zuexact adds no packages beyond those that come with R.

Depends (1)

R >= 4.1

Imports (0)

none

LinkingTo (0)

none

Suggests (7)

gmp knitrparallelPreciseSums rmarkdown testthat (>= 3.0.0)withr

Enhances (0)

none

Dependency license breakdown →

Reverse dependencies

0direct

0indirect

Nothing depends on this yet.

How these are counted

Code & Tests

People & History

People (2)

Pedro Baltazar

Radford M. Neal

Copyright holder

Author of the vendored 'xsum' library

Releases (1)

0.1.0Latest
record
2026-10-22 · current release ·
8 days in CRAN's queue
Listed in CRAN's incoming queue from 2026-10-14 00:46 to 2026-10-22 06:53 UTC, in 50 readings.
R
R 4.6.0 released · 2026-04-24

Across CRAN, the median accepted release of the past year spent 26 hours in the queue, 90% under 11 days.How queue time is measured

Package metadata

First published: 2026-10-22
Total releases: 1 / 1 yrs
License: MIT + file LICENSE OSI
Minimum R: ≥ 4.1
Download size: 82 KB

Cite

Cite this package

Run in R for the authors' preferred citation:

citation("zuexact")

Format

Baltazar, P., & Neal, R. M. (2026). zuexact: Exactly Rounded Sums, Means and Dot Products (Version 0.1.0) [Computer software]. https://doi.org/10.32614/CRAN.package.zuexact

This package has no citation file, so citation() returns this entry built from DESCRIPTION.

Cite the R Observatory

For a number measured here: a download total, a coverage figure, an archival date.

Format

APA

Balamuta, J. J. (2026). R Observatory: Metrics for zuexact version 0.1.0 [Data set]. HJJB, LLC. Data release v2026-10-25. https://doi.org/10.5281/zenodo.21843040

From data release v2026-10-25, which the citation names so these numbers can be found later. More on citing and the projects behind them.

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