[Rcpp-commits] r1675 - in pkg/Rcpp/inst: include/Rcpp/sugar/functions unitTests

[noreply at r-forge.r-project.org]

Author: romain
Date: 2010-06-23 16:57:12 +0200 (Wed, 23 Jun 2010)
New Revision: 1675

Added:
   pkg/Rcpp/inst/include/Rcpp/sugar/functions/diff.h
   pkg/Rcpp/inst/unitTests/runit.sugar.diff.R
Modified:
   pkg/Rcpp/inst/include/Rcpp/sugar/functions/functions.h
Log:
new sugar function : diff

Added: pkg/Rcpp/inst/include/Rcpp/sugar/functions/diff.h
===================================================================
--- pkg/Rcpp/inst/include/Rcpp/sugar/functions/diff.h	                        (rev 0)
+++ pkg/Rcpp/inst/include/Rcpp/sugar/functions/diff.h	2010-06-23 14:57:12 UTC (rev 1675)
@@ -0,0 +1,105 @@
+// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 8 -*-
+//
+// diff.h: Rcpp R/C++ interface class library -- diff
+//
+// Copyright (C) 2010 Dirk Eddelbuettel and Romain Francois
+//
+// This file is part of Rcpp.
+//
+// Rcpp is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// Rcpp is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Rcpp.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef Rcpp__sugar__diff_h
+#define Rcpp__sugar__diff_h
+
+namespace Rcpp{
+namespace sugar{
+	
+	// NOTE: caching the previous value so that we only have to fetch the 
+	//       value once only works because we process the object from left to 
+	//       right
+template <int RTYPE, bool LHS_NA, typename LHS_T>
+class Diff : public Rcpp::VectorBase< RTYPE, LHS_NA , Diff<RTYPE,LHS_NA,LHS_T> > {
+public:
+	typedef typename Rcpp::VectorBase<RTYPE,LHS_NA,LHS_T> LHS_TYPE ;
+	typedef typename Rcpp::traits::storage_type<RTYPE>::type STORAGE ;
+	
+	Diff( const LHS_TYPE& lhs_ ) : lhs(lhs_), previous(lhs_[0]), was_na(false) {
+		was_na = traits::is_na<RTYPE>(previous) ;
+	}
+	
+	inline STORAGE operator[]( int i ) const {
+		STORAGE y = lhs[i+1] ;
+		if( was_na ){
+			previous = y ;
+			was_na = traits::is_na<RTYPE>(y) ;
+			return previous ; // NA
+		}
+		if( traits::is_na<RTYPE>(y) ) {
+			was_na = true ;
+			previous = y ;
+			return previous ; // NA
+		}
+		STORAGE res = y - previous ;
+		previous = y ;
+		was_na = false ;
+		return res ;
+	}
+	inline int size() const { return lhs.size() - 1 ; }
+	         
+private:
+	const LHS_TYPE& lhs ;
+	mutable STORAGE previous ;
+	mutable bool was_na ;
+} ;
+
+template <int RTYPE, typename LHS_T>
+class Diff<RTYPE,false,LHS_T> : public Rcpp::VectorBase< RTYPE, false , Diff<RTYPE,false,LHS_T> > {
+public:
+	typedef typename Rcpp::VectorBase<RTYPE,false,LHS_T> LHS_TYPE ;
+	typedef typename Rcpp::traits::storage_type<RTYPE>::type STORAGE ;
+	
+	Diff( const LHS_TYPE& lhs_ ) : lhs(lhs_) {}
+	
+	inline STORAGE operator[]( int i ) const {
+		STORAGE y = lhs[i+1] ;
+		STORAGE diff = y - previous ;
+		previous = y ;
+		return y - previous ;
+	}
+	inline int size() const { return lhs.size() - 1 ; }
+	         
+private:
+	const LHS_TYPE& lhs ;
+	mutable STORAGE previous ;
+} ;
+
+} // sugar
+
+template <bool LHS_NA, typename LHS_T>
+inline sugar::Diff<INTSXP,LHS_NA,LHS_T> diff( 
+	const VectorBase<INTSXP,LHS_NA,LHS_T>& lhs
+	){
+	return sugar::Diff<INTSXP,LHS_NA,LHS_T>( lhs ) ;
+}
+
+template <bool LHS_NA, typename LHS_T>
+inline sugar::Diff<REALSXP,LHS_NA,LHS_T> diff( 
+	const VectorBase<REALSXP,LHS_NA,LHS_T>& lhs
+	){
+	return sugar::Diff<REALSXP,LHS_NA,LHS_T>( lhs ) ;
+}
+
+} // Rcpp
+#endif
+

Modified: pkg/Rcpp/inst/include/Rcpp/sugar/functions/functions.h
===================================================================
--- pkg/Rcpp/inst/include/Rcpp/sugar/functions/functions.h	2010-06-23 14:43:12 UTC (rev 1674)
+++ pkg/Rcpp/inst/include/Rcpp/sugar/functions/functions.h	2010-06-23 14:57:12 UTC (rev 1675)
@@ -32,5 +32,6 @@
 #include <Rcpp/sugar/functions/pmin.h>
 #include <Rcpp/sugar/functions/pmax.h>
 #include <Rcpp/sugar/functions/sign.h>
+#include <Rcpp/sugar/functions/diff.h>
 
 #endif

Added: pkg/Rcpp/inst/unitTests/runit.sugar.diff.R
===================================================================
--- pkg/Rcpp/inst/unitTests/runit.sugar.diff.R	                        (rev 0)
+++ pkg/Rcpp/inst/unitTests/runit.sugar.diff.R	2010-06-23 14:57:12 UTC (rev 1675)
@@ -0,0 +1,34 @@
+#!/usr/bin/r -t
+#
+# Copyright (C) 2010	Dirk Eddelbuettel and Romain Francois
+#
+# This file is part of Rcpp.
+#
+# Rcpp is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# Rcpp is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Rcpp.  If not, see <http://www.gnu.org/licenses/>.
+
+test.sugar.diff <- function( ){
+
+	fx <- cxxfunction( signature( x = "numeric" ), '
+	
+		NumericVector xx(x) ;
+		NumericVector res = diff( xx );
+		
+		return res ;
+	
+	', plugin = "Rcpp" )
+	
+	x <- rnorm( 100 )
+	checkEquals( fx(x) , diff(x) )
+}
+