fastverse · SebKrantz · Dec 22, 2025 · Dec 22, 2025 · Dec 22, 2025 · Dec 22, 2025
diff --git a/DESCRIPTION b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: collapse
 Title: Advanced and Fast Data Transformation
-Version: 2.1.5.9000
-Date: 2025-12-02
+Version: 2.1.6
+Date: 2025-12-21
 Authors@R: c(
            person("Sebastian", "Krantz", role = c("aut", "cre"), 
                   email = "[email protected]", 

diff --git a/NEWS.md b/NEWS.md
@@ -1,8 +1,10 @@
-# collapse 2.1.5.9000
+# collapse 2.1.6
 
 * The repo has moved to `fastverse/collapse` and the website to [fastverse.org/collapse](https://fastverse.org/collapse/)---for better visibility and maintenance. Appropriate redirects from the old repo/site have been implemented.
   Selected people now have access to the repo through the organization account and may respond to issues or submit fixes. 
 
+* Added new AI-generated interactive/chattable [DeepWiki documentation](https://deepwiki.com/fastverse/collapse).
+
 * *collapse* now treats `-0` and `0` as the same value in hash functions (`funique()`, `group()`, `fmatch()`, `fndistinct()`, `fmode()`, and all higher-level derivatives). This is implemented by adding a value of `0.0` to double values before hashing them, and has a small (~3%) performance penalty when hashing doubles. It is implemented in synch with an [equivalent change in *Rcpp*](https://github.com/RcppCore/Rcpp/issues/1340). Thanks @mayer79 for reporting and helping with benchmarking the performance implications (#648). 
 
 * Fixed a bug in `pivot(..., how = "wider", FUN = "sum")` (using internal sum function) when columns to aggregate were integer typed. Thanks @ummel (#803). 
@@ -11,6 +13,8 @@
 
 * Faster installation from source thanks to the `#include <Rcpp/Lighter>` option in *Rcpp* which loads only part of the header files. Thanks @eddelbuettel for the hint. 
 
+* Consistency with internal updates to *data.table*. Thanks @aitap (https://github.com/fastverse/collapse/pull/809, https://github.com/Rdatatable/data.table/issues/7497).
+
 # collapse 2.1.5
 
 * Fixed small bugs/strange behavior in `collap()` when `g` was passed externally (as columns or *GRP* object). E.g., in `collap(x, g, w = ~ col)`, where `g` is a *GRP* object, the weights were aggregated twice: once using `FUN` (incorrect) and once using `wFUN`. 

diff --git a/README.md b/README.md
@@ -14,6 +14,7 @@
 [![dependencies](https://tinyverse.netlify.app/badge/collapse)](https://CRAN.R-project.org/package=collapse)
 [![DOI](https://zenodo.org/badge/172910283.svg)](https://zenodo.org/badge/latestdoi/172910283)
 [![arXiv](https://img.shields.io/badge/arXiv-2403.05038-0969DA.svg)](https://arxiv.org/abs/2403.05038)
+[![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/fastverse/collapse)
 <!-- badges: end -->
 
 *collapse* is a large C/C++-based package for data transformation and statistical computing in R. It aims to:

diff --git a/src/data.table_subset.c b/src/data.table_subset.c
@@ -104,10 +104,10 @@ static SEXP shallow(SEXP dt, SEXP cols, R_len_t n)
   // otherwise (if the SET were were first) the 100 tl is assigned to length.
   SET_LEN(newnames,l);
   SET_TRULEN(newnames,n);
-  SET_GROWABLE_BIT(newnames);
+  SET_GROWBL_BIT(newnames);
   SET_LEN(newdt,l);
   SET_TRULEN(newdt,n);
-  SET_GROWABLE_BIT(newdt);
+  SET_GROWBL_BIT(newdt);
   setselfref(newdt);
   UNPROTECT(protecti);
   return(newdt);

diff --git a/src/data.table_utils.c b/src/data.table_utils.c
@@ -38,7 +38,7 @@ SEXP setnames(SEXP x, SEXP nam) {
     memcpy(SEXPPTR(newnam), SEXPPTR_RO(nam), l*sizeof(SEXP));
     SET_LEN(newnam, l);
     SET_TRULEN(newnam, n);
-    SET_GROWABLE_BIT(newnam);
+    SET_GROWBL_BIT(newnam);
     setAttrib(x, R_NamesSymbol, newnam);
     setselfref(x);
     UNPROTECT(1);

diff --git a/src/internal/R_defn.h b/src/internal/R_defn.h
@@ -195,4 +195,10 @@ typedef union { VECTOR_SEXPREC s; double align; } SEXPREC_ALIGN;
 //   return DATAPTR(x);
 // }
 
+/* Growable vector support */
+#undef GROW_MSK
+#define GROW_MSK ((unsigned short)(1<<5))
+#undef SET_GROWBL_BIT
+#define SET_GROWBL_BIT(x) (((x)->sxpinfo.gp) |= GROW_MSK)
+
 #endif // End of R_DEFINITIONS_H guard
diff --git a/vignettes/collapse_documentation.Rmd b/vignettes/collapse_documentation.Rmd
@@ -16,7 +16,7 @@ vignette: >
 1. To facilitate complex data transformation, exploration and computing tasks in R.
 2. To help make R code fast, flexible, parsimonious and programmer friendly. 
 
-Documentation comes in 6 different forms:
+Documentation comes in 7 different forms:
 
 ## Built-In Structured Documentation
 
@@ -30,17 +30,27 @@ The package page under `help("collapse-package")` provides some general informat
 
 Reading `help("collapse-package")` and `help("collapse-documentation")` is the most comprehensive way to get acquainted with the package. `help("collapse-documentation")` is always the most up-to-date resource.
 
+## DeepWiki
+
+[DeepWiki](https://deepwiki.com/) is an AI-powered platform designed to automatically generate structured, interactive documentation for software repositories, primarily on GitHub. Developed by [Cognition AI](https://cognition.ai/)—the same laboratory behind the autonomous AI engineer [Devin](https://devin.ai/)—it serves as a dynamic, "Wikipedia-like" encyclopedia for codebases.
+
+While not more comprehensive or accurate than the structured documentation, it is great to learn more about the internal structure of *collapse* and use a chatbot (Devin) to ask questions about or write code using *collapse*. 
+
+You can access the *collapse* DeepWiki [here](https://deepwiki.com/fastverse/collapse).
+
 ## Cheatsheet
 
 An up-to-date (v2.0) [cheatsheet](<https://raw.githubusercontent.com/fastverse/collapse/master/misc/collapse%20cheat%20sheet/collapse_cheat_sheet.pdf>) compactly summarizes the package. 
 
 ## Article on arXiv
 
-An [article](https://arxiv.org/abs/2403.05038) on *collapse* is forthcoming at [Journal of Statistical Software](https://www.jstatsoft.org/). 
+An [article](https://arxiv.org/abs/2403.05038) on *collapse* is forthcoming at [Journal of Statistical Software](https://www.jstatsoft.org/) in early 2026. 
+
+## Presentations and Slides
 
-## useR 2022 Presentation and Slides
+- I have presented *collapse* (v1.8) in some level of detail at useR 2022. A 2h video recording that provides a quite comprehensive introduction is available [here](<https://www.youtube.com/watch?v=OwWT1-dSEts>). The corresponding slides are available [here](<https://raw.githubusercontent.com/fastverse/collapse/master/misc/useR2022%20presentation/collapse_useR2022_final.pdf>).
 
-I have presented collapse (v1.8) in some level of detail at useR 2022. A 2h video recording that provides a quite comprehensive introduction is available [here](<https://www.youtube.com/watch?v=OwWT1-dSEts>). The corresponding slides are available [here](<https://raw.githubusercontent.com/fastverse/collapse/master/misc/useR2022%20presentation/collapse_useR2022_final.pdf>).
+- I have recently presented *collapse* (v2.1) and the *fastverse* at a workshop on "[Speeding Up Empirical Research: Tools and Techniques for Fast Computing](https://www.bportugal.pt/en/evento/workshop-speeding-empirical-research-tools-and-techniques-fast-computing-bplim)" organized by the Bank of Portugal in December 2025. My 45-minute talk focused on two advanced applications in international trade and spatial network analysis/package development. You can find the materials (slides and recording) [here](https://github.com/BPLIM/Workshops/tree/master/BPLIM2025).
 
 ## Vignettes