complex support (closes #221)

Author: eddelbuettel

ChangeLog

@@ -1,6 +1,6 @@
 2014-12-31  Dirk Eddelbuettel  <edd@debian.org>
 
-        * inst/include/Rcpp/sugar/functions/mean.h: Support INTSXP  
+        * inst/include/Rcpp/sugar/functions/mean.h: Support int and complex
 
 2014-12-30  Dirk Eddelbuettel  <edd@debian.org>
 

inst/NEWS.Rd

@@ -19,7 +19,7 @@
       \item Sorting is now prohibited at compile time for objects of type
       \code{List}, \code{RawVector} and \code{ExpressionVector}.
       \item Vectors now have a \code{Vector::const\_iterator} that is 'const correct'
-      thanks to fix by Romain following bug report in rcpp-devel by Martyn Plummer 
+      thanks to fix by Romain following bug report in rcpp-devel by Martyn Plummer.
       \item The \code{mean()} sugar function now uses a more robust two-pass method.
     }
     \item Changes in Rcpp Attributes:

inst/include/Rcpp/sugar/functions/mean.h

@@ -52,6 +52,43 @@ class Mean : public Lazy<typename Rcpp::traits::storage_type<RTYPE>::type, Mean<
     const VEC_TYPE& object ;
 };
 
+template <bool NA, typename T>
+class Mean<CPLXSXP,NA,T> : public Lazy<Rcomplex, Mean<CPLXSXP,NA,T> > {
+public:
+    typedef typename Rcpp::VectorBase<CPLXSXP,NA,T> VEC_TYPE;
+
+    Mean(const VEC_TYPE& object_) : object(object_) {}
+
+    Rcomplex get() const {
+        ComplexVector input = object;
+        int n = input.size();           // double pass (as in summary.c)
+        long double s = 0.0, si = 0.0;
+        for (int i=0; i<n; i++) {
+            Rcomplex z = input[i];
+            s += z.r;
+            si += z.i;
+        }
+        s /= n;
+        si /= n;
+        if (R_FINITE((double)s) && R_FINITE((double)si)) {
+            long double t = 0.0, ti = 0.0;
+            for (int i = 0; i < n; i++) {
+                Rcomplex z = input[i];
+                t += z.r - s;
+                ti += z.i - si;
+            }
+            s += t/n;
+            si += ti/n;
+        }
+        Rcomplex z;
+        z.r = s;
+        z.i = si;
+        return z;
+    }
+private:
+    const VEC_TYPE& object ;
+};
+
 } // sugar
 
 template <bool NA, typename T>
@@ -64,6 +101,11 @@ inline sugar::Mean<INTSXP,NA,T> mean(const VectorBase<INTSXP,NA,T>& t) {
     return sugar::Mean<INTSXP,NA,T>(t);
 }
 
+template <bool NA, typename T>
+inline sugar::Mean<CPLXSXP,NA,T> mean(const VectorBase<CPLXSXP,NA,T>& t) {
+    return sugar::Mean<CPLXSXP,NA,T>(t);
+}
+
 } // Rcpp
 #endif