Tomas Kalibera
2019-Oct-25 15:13 UTC
[Rd] Unexpected behavior when using macro to loop over vector
On 10/25/19 11:01 AM, Tomas Kalibera wrote:> On 10/23/19 6:45 AM, Wang Jiefei wrote: >> Hi all, >> >> I found an unexpected behavior when I was trying to use the macro >> defined >> in "R_ext/Itermacros.h"? to loop over an atomic vector. Here is a >> minimum >> example: >> >> C++ code >> ``` >> #include "R_ext/Itermacros.h" >> #define GET_REGION_BUFSIZE 2 >> //Redefine the macro since C++ is not happy with the implicit type >> conversion >> #define ITERATE_BY_REGION_PARTIAL(sx, px, idx, nb, etype, vtype, \ >> ? strt, nfull, expr) do { \ >> const etype *px = (etype*)DATAPTR_OR_NULL(sx); \ >> if (px != NULL) { \ >> ??? R_xlen_t __ibr_n__ = strt + nfull; \ >> ??? R_xlen_t nb = __ibr_n__; \ >> ??? for (R_xlen_t idx = strt; idx < __ibr_n__; idx += nb) { \ >> expr \ >> ???? } \ >> } \ >> else ITERATE_BY_REGION_PARTIAL0(sx, px, idx, nb, etype, vtype, \ >> strt, nfull, expr); \ >> ???? } while (0) >> // [[Rcpp::export]] >> void C_testPrint(SEXP x) { >> ITERATE_BY_REGION_PARTIAL(x, ptr, idx, nbatch, double, REAL, 1, 4, { >> for (R_xlen_t i = 0; i < nbatch; i++) >> Rprintf("idx: %lld, i: %lld, ptr:%f\n", idx, i, ptr[i]); > > You need to index "ptr" by "idx + i", not by "i". Have a look at how > the macros are used in R, e.g. printvector.c.Actually, the macro should do this for you, we will investigate/fix. Thanks for the report! Best Tomas> > Best, > Tomas > >> }); >> } >> ``` >> >> The function C_testPrint loops over its argument x and prints out one >> value >> of x at each loop. The loop starts from the second element and ends >> in the >> fifth element of x. I also redefine the buffer size to see the effect of >> it. Here is my R code: >> >> R code >> ``` >>> C_testPrint(as.numeric(1:10)) >> idx: 1, i: 0, ptr:2.000000 >> idx: 1, i: 1, ptr:3.000000 >> idx: 3, i: 0, ptr:4.000000 >> idx: 3, i: 1, ptr:5.000000 >>> C_testPrint(c(1,2,3,4,5,6,7,8,9,10)) >> idx: 1, i: 0, ptr:1.000000 >> idx: 1, i: 1, ptr:2.000000 >> idx: 1, i: 2, ptr:3.000000 >> idx: 1, i: 3, ptr:4.000000 >> idx: 1, i: 4, ptr:5.000000 >> ``` >> >> There are two problems in the outputs: >> 1. The numbers of lines are different >> 2. The starting indices are not the same. >> >> ?From my understanding, the first output seems correct to me. The >> second is >> not unexpected. I believe the differences are due to the >> accessibility of >> the data pointer. Did I misunderstand and misuse the macro? Or is it >> a bug >> in R? Here is my session info. My R is a bit outdated but the macro >> seems >> unchanged in R 4.0. Thanks >> >> ``` >>> sessionInfo() >> R Under development (unstable) (2019-08-22 r77060) >> Platform: x86_64-w64-mingw32/x64 (64-bit) >> Running under: Windows >= 8 x64 (build 9200) >> ``` >> >> ????[[alternative HTML version deleted]] >> >> ______________________________________________ >> R-devel at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > >
Wang Jiefei
2019-Oct-25 15:20 UTC
[Rd] Unexpected behavior when using macro to loop over vector
Thank you, Tomas. I appreciate your help. BTW, could you also add an explicit type conversion in " ITERATE_BY_REGION_PARTIAL" macro while you are fixing the bug? C++ compiler does not happy with the implicit conversion from void* to T* somehow and I have to redefine it before using the macro. Best, Jiefei On Fri, Oct 25, 2019 at 11:13 AM Tomas Kalibera <tomas.kalibera at gmail.com> wrote:> On 10/25/19 11:01 AM, Tomas Kalibera wrote: > > On 10/23/19 6:45 AM, Wang Jiefei wrote: > >> Hi all, > >> > >> I found an unexpected behavior when I was trying to use the macro > >> defined > >> in "R_ext/Itermacros.h" to loop over an atomic vector. Here is a > >> minimum > >> example: > >> > >> C++ code > >> ``` > >> #include "R_ext/Itermacros.h" > >> #define GET_REGION_BUFSIZE 2 > >> //Redefine the macro since C++ is not happy with the implicit type > >> conversion > >> #define ITERATE_BY_REGION_PARTIAL(sx, px, idx, nb, etype, vtype, \ > >> strt, nfull, expr) do { \ > >> const etype *px = (etype*)DATAPTR_OR_NULL(sx); \ > >> if (px != NULL) { \ > >> R_xlen_t __ibr_n__ = strt + nfull; \ > >> R_xlen_t nb = __ibr_n__; \ > >> for (R_xlen_t idx = strt; idx < __ibr_n__; idx += nb) { \ > >> expr \ > >> } \ > >> } \ > >> else ITERATE_BY_REGION_PARTIAL0(sx, px, idx, nb, etype, vtype, \ > >> strt, nfull, expr); \ > >> } while (0) > >> // [[Rcpp::export]] > >> void C_testPrint(SEXP x) { > >> ITERATE_BY_REGION_PARTIAL(x, ptr, idx, nbatch, double, REAL, 1, 4, { > >> for (R_xlen_t i = 0; i < nbatch; i++) > >> Rprintf("idx: %lld, i: %lld, ptr:%f\n", idx, i, ptr[i]); > > > > You need to index "ptr" by "idx + i", not by "i". Have a look at how > > the macros are used in R, e.g. printvector.c. > > Actually, the macro should do this for you, we will investigate/fix. > Thanks for the report! > > Best > Tomas > > > > > Best, > > Tomas > > > >> }); > >> } > >> ``` > >> > >> The function C_testPrint loops over its argument x and prints out one > >> value > >> of x at each loop. The loop starts from the second element and ends > >> in the > >> fifth element of x. I also redefine the buffer size to see the effect of > >> it. Here is my R code: > >> > >> R code > >> ``` > >>> C_testPrint(as.numeric(1:10)) > >> idx: 1, i: 0, ptr:2.000000 > >> idx: 1, i: 1, ptr:3.000000 > >> idx: 3, i: 0, ptr:4.000000 > >> idx: 3, i: 1, ptr:5.000000 > >>> C_testPrint(c(1,2,3,4,5,6,7,8,9,10)) > >> idx: 1, i: 0, ptr:1.000000 > >> idx: 1, i: 1, ptr:2.000000 > >> idx: 1, i: 2, ptr:3.000000 > >> idx: 1, i: 3, ptr:4.000000 > >> idx: 1, i: 4, ptr:5.000000 > >> ``` > >> > >> There are two problems in the outputs: > >> 1. The numbers of lines are different > >> 2. The starting indices are not the same. > >> > >> From my understanding, the first output seems correct to me. The > >> second is > >> not unexpected. I believe the differences are due to the > >> accessibility of > >> the data pointer. Did I misunderstand and misuse the macro? Or is it > >> a bug > >> in R? Here is my session info. My R is a bit outdated but the macro > >> seems > >> unchanged in R 4.0. Thanks > >> > >> ``` > >>> sessionInfo() > >> R Under development (unstable) (2019-08-22 r77060) > >> Platform: x86_64-w64-mingw32/x64 (64-bit) > >> Running under: Windows >= 8 x64 (build 9200) > >> ``` > >> > >> [[alternative HTML version deleted]] > >> > >> ______________________________________________ > >> R-devel at r-project.org mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-devel > > > > > >[[alternative HTML version deleted]]
Tomas Kalibera
2019-Oct-25 17:19 UTC
[Rd] Unexpected behavior when using macro to loop over vector
On 10/25/19 5:20 PM, Wang Jiefei wrote:> Thank you, Tomas. I appreciate your help. BTW, could you also add an > explicit type conversion in " ITERATE_BY_REGION_PARTIAL" macro while > you are fixing the bug? C++ compiler does not happy with the implicit > conversion from void* to T* somehow and I have to redefine it before > using the macro.Yes, C++ requires a cast from void to non-void pointer. Fixed now in R-devel (77331): your example iterator should now work also for the non-compact sequence. Best Tomas> > Best, > Jiefei > > On Fri, Oct 25, 2019 at 11:13 AM Tomas Kalibera > <tomas.kalibera at gmail.com <mailto:tomas.kalibera at gmail.com>> wrote: > > On 10/25/19 11:01 AM, Tomas Kalibera wrote: > > On 10/23/19 6:45 AM, Wang Jiefei wrote: > >> Hi all, > >> > >> I found an unexpected behavior when I was trying to use the macro > >> defined > >> in "R_ext/Itermacros.h"? to loop over an atomic vector. Here is a > >> minimum > >> example: > >> > >> C++ code > >> ``` > >> #include "R_ext/Itermacros.h" > >> #define GET_REGION_BUFSIZE 2 > >> //Redefine the macro since C++ is not happy with the implicit type > >> conversion > >> #define ITERATE_BY_REGION_PARTIAL(sx, px, idx, nb, etype, vtype, \ > >> ? strt, nfull, expr) do { \ > >> const etype *px = (etype*)DATAPTR_OR_NULL(sx); \ > >> if (px != NULL) { \ > >> ??? R_xlen_t __ibr_n__ = strt + nfull; \ > >> ??? R_xlen_t nb = __ibr_n__; \ > >> ??? for (R_xlen_t idx = strt; idx < __ibr_n__; idx += nb) { \ > >> expr \ > >> ???? } \ > >> } \ > >> else ITERATE_BY_REGION_PARTIAL0(sx, px, idx, nb, etype, vtype, \ > >> strt, nfull, expr); \ > >> ???? } while (0) > >> // [[Rcpp::export]] > >> void C_testPrint(SEXP x) { > >> ITERATE_BY_REGION_PARTIAL(x, ptr, idx, nbatch, double, REAL, 1, > 4, { > >> for (R_xlen_t i = 0; i < nbatch; i++) > >> Rprintf("idx: %lld, i: %lld, ptr:%f\n", idx, i, ptr[i]); > > > > You need to index "ptr" by "idx + i", not by "i". Have a look at > how > > the macros are used in R, e.g. printvector.c. > > Actually, the macro should do this for you, we will investigate/fix. > Thanks for the report! > > Best > Tomas > > > > > Best, > > Tomas > > > >> }); > >> } > >> ``` > >> > >> The function C_testPrint loops over its argument x and prints > out one > >> value > >> of x at each loop. The loop starts from the second element and > ends > >> in the > >> fifth element of x. I also redefine the buffer size to see the > effect of > >> it. Here is my R code: > >> > >> R code > >> ``` > >>> C_testPrint(as.numeric(1:10)) > >> idx: 1, i: 0, ptr:2.000000 > >> idx: 1, i: 1, ptr:3.000000 > >> idx: 3, i: 0, ptr:4.000000 > >> idx: 3, i: 1, ptr:5.000000 > >>> C_testPrint(c(1,2,3,4,5,6,7,8,9,10)) > >> idx: 1, i: 0, ptr:1.000000 > >> idx: 1, i: 1, ptr:2.000000 > >> idx: 1, i: 2, ptr:3.000000 > >> idx: 1, i: 3, ptr:4.000000 > >> idx: 1, i: 4, ptr:5.000000 > >> ``` > >> > >> There are two problems in the outputs: > >> 1. The numbers of lines are different > >> 2. The starting indices are not the same. > >> > >> ?From my understanding, the first output seems correct to me. The > >> second is > >> not unexpected. I believe the differences are due to the > >> accessibility of > >> the data pointer. Did I misunderstand and misuse the macro? Or > is it > >> a bug > >> in R? Here is my session info. My R is a bit outdated but the > macro > >> seems > >> unchanged in R 4.0. Thanks > >> > >> ``` > >>> sessionInfo() > >> R Under development (unstable) (2019-08-22 r77060) > >> Platform: x86_64-w64-mingw32/x64 (64-bit) > >> Running under: Windows >= 8 x64 (build 9200) > >> ``` > >> > >> ????[[alternative HTML version deleted]] > >> > >> ______________________________________________ > >> R-devel at r-project.org <mailto:R-devel at r-project.org> mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-devel > > > > >[[alternative HTML version deleted]]
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