add explicit 'RcppParallelSIMD.h' header

Author: kevinushey

examples/boost-simd-abssum.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/boost-simd-accumulate.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/boost-simd-capabilities.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/boost-simd-dot.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/boost-simd-hello-world.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/boost-simd-transform.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 using namespace Rcpp;
 

examples/rcpp-simd-transform.cpp

@@ -1,5 +1,5 @@
 // [[Rcpp::depends(RcppParallel)]]
-#include <RcppParallel.h>
+#include <RcppParallelSIMD.h>
 #include <Rcpp.h>
 
 using namespace Rcpp;

inst/include/RcppParallel.h

@@ -5,9 +5,6 @@
 // TinyThread implementation
 #include "RcppParallel/TinyThread.h"
 
-// SIMD Wrappers
-#include "RcppParallel/SIMD.h"
-
 // Use TBB only where it's known to compile and work correctly
 // (NOTE: Windows TBB is temporarily opt-in for packages for 
 // compatibility with CRAN packages not previously configured

inst/include/RcppParallelSIMD.h

@@ -0,0 +1,7 @@
+#ifndef __RCPP_PARALLEL_SIMD_H__
+#define __RCPP_PARALLEL_SIMD_H__
+
+#include "RcppParallel.h"
+#include "RcppParallel/SIMD.h"
+
+#endif /* __RCPP_PARALLEL_SIMD_H__ */

vignettes/simd-operations.Rmd

@@ -11,7 +11,7 @@ vignette: >
 
 Modern CPU processors are built with new, extended instruction sets that optimize for certain operations. A class of these allow for vectorized operations, called Single Instruction / Multiple Data (SIMD) instructions. Although modern compilers will use these instructions when possible, it is often not possible for the compiler to reason about whether or not a particular block of code can be executed using SIMD instructions.
 
-`Boost.SIMD` is a (proposed) C++ header-only libary, that makes it possible to explicitly request the use of SIMD instructions when possible, while falling back to regular scalar operations if not. `RcppParallel` wraps and exposes this library for use with R vectors.
+`Boost.SIMD` is a C++ header-only libary that makes it possible to explicitly request the use of SIMD instructions when possible, while falling back to regular scalar operations if not. `RcppParallel` wraps and exposes this library for use with R vectors.
 
 Here's a quick example of how we might compute the sum of elements in a vector, using `Boost.SIMD`. 
 
@@ -34,6 +34,8 @@ struct add_two {
 
 // [[Rcpp::export]]
 double simd_sum(NumericVector x) {
+   // Use 'simd::accumulate', to sum our vector (by successively adding
+   // up pairwise components of the vector)
    return simd::accumulate(x, 0.0, add_two());
 }
 ```
@@ -52,3 +54,21 @@ Boost.SIMD provides two primary abstractions for the implementation of SIMD algo
 - `simd::transform()`,  for vector -> vector transformations.
 
 These functions operate like their `std::` counterparts, but expect a functor with a templated call operator. By making the call operator templated, `Boost.SIMD` can generate code using its own optimized SIMD functions when appropriate, and fall back to a default implementation (based on the types provided) when not.
+
+`Boost.SIMD` also provides a number of builtin functions, which can be used effectively with `simd::accumulate()` or `simd::transform()`. For example, let's use SIMD instructions to compute the minimum:
+
+```{r, engine='Rcpp'}
+// [[Rcpp::depends(RcppParallel)]]
+#include <RcppParallel.h>
+#include <Rcpp.h>
+
+#include <boost/simd/arithmetic/functions/min.hpp>
+
+using namespace RcppParallel;
+using namespace Rcpp;
+
+// [[Rcpp::export]]
+NumericVector simd_min(NumericVector data) {
+   return simd::transform(data, boost::simd::tag::min_());
+}
+```