croposp [WP][FEATURE]: implement triple indexer

src/ts/croposp/triples.cc

@@ -61,8 +61,28 @@ namespace croposp {
                                    const unsigned int& l) const
   {
     unsigned int retval=0;
+    unsigned int npairs=this->pairs();
+    unsigned int size=this->size();
     TFXX_assert((i!=k) && (k!=l) && (l!=i),
-                "triple indices must be unique");
+                "triple indices must be unique; report this as a bug");
+    TFXX_assert((i<size) && (k<size) && (l<size),
+                "index value(s) out of range; report this as a bug");
+    if (this->Mpairs_first)
+    {
+      unsigned int ii=i;
+      if (ii>k) { --ii; }
+      if (ii>l) { --ii; }
+      retval=this->Mpairs.operator()(k,l)+ii*npairs;
+    }
+    else
+    {
+      croposp::Pairs pairs(size-1);
+      unsigned int kk=k;
+      unsigned int ll=l;
+      if (kk>i) { --kk; }
+      if (ll>i) { --ll; }
+      retval=pairs(kk,ll)+i*npairs;
+    }
     return(retval);
   } // unsigned int Triples::operator()(const unsigned int& i,
     //                                  const unsigned int& k,