search for: altreps

...bject. If we change n from 100 to 10 and check the >> internal again, alt2 will not get wrapped. > > > Right, so this is a misunderstanding (which may be the fault of sparse > documentation on our part); wrapper is one particular ALTREP class, its > not a fundamental aspect of ALTREPs themselves. Most ALTREP objects do not > have wrappers. See, e.g., > > > .Internal(inspect(1:4)) > > @7fb727d6be50 13 INTSXP g0c0 [NAM(3)] 1 : 4 (compact) > > > That's an ALTREP with no wrapper (a compact sequence). The wrapper ALTREP > class is for attaching meta...

Hello, I have encountered two bugs when using ALTREP APIs. 1. STDVEC_DATAPTR >From RInternal.h file it has a comment: /* ALTREP support */ > void *(STDVEC_DATAPTR)(SEXP x); However, this comment might not be true, the easiest way to verify it is to define a C++ function: void C_testFunc(SEXP a) > { > STDVEC_DATAPTR(a); > } and call it in R via > a=1:10 > >

...ted with by > non-ALTREP-implementing package code, *more-or-less *exactly as standard > (non-AR) SEXPs are: via the published C API. The more or less comes from > the fact that in some cases, doing things that are good ideas on standard > SEXPS will work, but may not be a good idea for ALTREPs. > > The most "low-hanging-fruit" example of something that was best practice > for standard vectors but is not a good idea for ALTREP vectors is grabbing > a DATAPTR and iterating over the values without modification in a tight > loop. This will work (absent allocation f...

thanks for clearing that up, so these methods are actually not meant to be exported on Windows and OSX? Some of the ALTREP methods that now use 'attribute_hidden' would be very useful to packages that aim to be ALTREP aware, should the currently (exported) API be considered final? thanks for your time & best, Mark On Tue, Jun 4, 2019 at 6:52 PM Tierney, Luke <luke-tierney at

Hi Yutani, ALTREP is part of the official R api, as illustrated by the presence of src/include/R_ext/Altrep.h. Everything declared in the header files in that directory is official API AFAIK (and I believe that is more definitive than the manuals). The documentation of ALTREP has lagged behind its implementation unfortunately, which may partially my fault for not submitting doc patches for it

Thanks, Hernando, Sorry, "API" is a bit confusing term in this context, but what I want to discuss is the "API" that Writing R Extension defines as quoted in my previous email. It's probably different from an ordinary sense when we casually say "R C API". You might wonder why I care about such a difference. This is because calling a "non-API" is

Hi all, The coercion function defined for the ALTREP object will not be called by R when an assignment operation implicitly introduces coercion for a large ALTREP object. For example, If I create a vector of length 10, the ALTREP coercion function seems to work fine. ``` > x <- 1:10 > y <- wrap_altrep(x) > .Internal(inspect(y)) @0x000000001f9271c0 13 INTSXP g0c0 [REF(2)] I am

...om 100 to 10 and check the >>> internal again, alt2 will not get wrapped. >> >> >> Right, so this is a misunderstanding (which may be the fault of sparse >> documentation on our part); wrapper is one particular ALTREP class, its >> not a fundamental aspect of ALTREPs themselves. Most ALTREP objects do not >> have wrappers. See, e.g., >> >> > .Internal(inspect(1:4)) >> >> @7fb727d6be50 13 INTSXP g0c0 [NAM(3)] 1 : 4 (compact) >> >> >> That's an ALTREP with no wrapper (a compact sequence). The wrapper ALTREP...

...gt; always wrap an ALTREP object. If we change n from 100 to 10 and check the > internal again, alt2 will not get wrapped. Right, so this is a misunderstanding (which may be the fault of sparse documentation on our part); wrapper is one particular ALTREP class, its not a fundamental aspect of ALTREPs themselves. Most ALTREP objects do not have wrappers. See, e.g., > .Internal(inspect(1:4)) @7fb727d6be50 13 INTSXP g0c0 [NAM(3)] 1 : 4 (compact) That's an ALTREP with no wrapper (a compact sequence). The wrapper ALTREP class is for attaching metadata (known sortedness, known lack of NAs...

> On Apr 22, 2024, at 7:37 PM, Gabriel Becker <gabembecker at gmail.com> wrote: > > Hi Yutani, > > ALTREP is part of the official R api, as illustrated by the presence of > src/include/R_ext/Altrep.h. Everything declared in the header files in that > directory is official API AFAIK (and I believe that is more definitive than > the manuals). > That is not true

Hi devel team, I'm working on C/C++ level ALTREP compatibility for a package. The package previously used pointers to access the data of a SEXP, so it would not work for some ALTREP objects which do not have a pointer. I plan to rewrite the code and use functions like get_elt, get_region, and get_subset to access the values of a vector, so I have a few questions for ALTREP: 1. Since an

Hello, I don't believe it is illegal, as ALTREP "implements an abstraction underneath the C API". And is "compatible with all code which uses the API". Please see slide deck by Gabriel Becker, with L Tierney, M Lawrence and T Kalibera. https://bioconductor.org/help/course-materials/2020/BiocDevelForum/16-ALTREP .pdf ALTREP framework implements an abstraction underneath

...signed to be interacted with by non-ALTREP-implementing package code, *more-or-less *exactly as standard (non-AR) SEXPs are: via the published C API. The more or less comes from the fact that in some cases, doing things that are good ideas on standard SEXPS will work, but may not be a good idea for ALTREPs. The most "low-hanging-fruit" example of something that was best practice for standard vectors but is not a good idea for ALTREP vectors is grabbing a DATAPTR and iterating over the values without modification in a tight loop. This will work (absent allocation failure or, I suppose, th...

Thanks for your convincing comment, but it seems the R core team has a different opinion... A few hours ago, src/include/R_ext/Altrep.h got this comment: /* Not part of the API, subject to change at any time. */ commit: https://github.com/r-devel/r-svn/commit/2059bffde642f8426d1f39ab5dd995d19a575d4d While I'm glad to see their attempt to make it clear, I'm confused. That

...> non-ALTREP-implementing package code, *more-or-less *exactly as standard >> (non-AR) SEXPs are: via the published C API. The more or less comes from >> the fact that in some cases, doing things that are good ideas on standard >> SEXPS will work, but may not be a good idea for ALTREPs. >> >> The most "low-hanging-fruit" example of something that was best practice >> for standard vectors but is not a good idea for ALTREP vectors is grabbing >> a DATAPTR and iterating over the values without modification in a tight >> loop. This will work (...

Hi all, I believe I have found a bug (or perhaps just an oversight) with the ALTREP wrapper classes. The short form of this is that I believe that the wrapper classes need to override the default ALTREP `Extract_subset_method()` with a method that calls `Extract_subset()` on the "wrapped" object. I have a patch prepared here: https://github.com/DavisVaughan/r-source/pull/1 There is

Hi Gabriel, here is a simple package for reproducing the problem. https://github.com/Jiefei-Wang/testPkg Best, Jiefei On Thu, Oct 8, 2020 at 5:04 AM Gabriel Becker <gabembecker at gmail.com> wrote: > Jiefei, > > Where does the code for your altrep class live? > > Thanks, > ~G > > On Wed, Oct 7, 2020 at 4:25 AM Jiefei Wang <szwjf08 at gmail.com> wrote: >

Writing R Extension[1] defines "API" as: Entry points which are documented in this manual and declared in an installed header file. These can be used in distributed packages and will only be changed after deprecation. But, the document (WRE) doesn't have even a single mention of ALTREP, the term "ALTREP" itself or any entry points related to ALTREP. Does this mean,

Hi Kylie, Is it a list with only numerics in it? (I only see REALSXPs there, but obviously inspect isn't showing all of them). If so, you could load it up into one big vector and then also keep partitioning information around. Bioconductor does this (see ?IRanges::CompressedList ). The potential benefit here being that the underlying large vector could then be a big out-of-memory altrep. How

...do part of it yo'll either need custom breaking for both inner and >>> outer loopsl, or in R-devel you can use ITERATE_BY_REGION_PARTIAL >>> - Don't use the variants ending in 0, all they do is skip over >>> things that are a good idea in the case of non-altreps (and some very >>> specific altreps). >>> >>> Hope that helps. >>> >>> Best, >>> ~G >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> &g...