working on tensor class

tensor.cc

@@ -21,12 +21,98 @@
 #include "laerror.h"
 #include "qsort.h"
 #include "miscfunc.h"
+#include <complex>
 
 
 namespace LA {
 
+LA_largeindex subindex(int *sign, const INDEXGROUP &g, const NRVec<LA_index> &I) //index of one subgroup 
+{
+#ifdef DEBUG
+if(I.size()<=0) laerror("empty index group in subindex");
+if(g.number!=I.size()) laerror("mismatch in the number of indices in a group");
+for(int i=0; i<I.size(); ++i) if(I[i]<g.offset || I[i] >= g.offset+g.range) laerror("index out of range in tensor subindex");
+#endif
+
+switch(I.size()) //a few special cases for efficiency
+	{
+	case 0:
+		*sign=0;
+		return 0;
+		break;
+	case 1:
+		*sign=1;
+		return I[0]-g.offset;
+		break;
+	case 2:
+		{
+		*sign=1;
+		if(g.symmetry==0) return (I[1]-g.offset)*g.range+I[0]-g.offset;
+		LA_index i0,i1;
+		if(I[0]>I[1]) {i1=I[0]; i0=I[1]; if(g.symmetry<0) *sign = -1;} else {i1=I[1]; i0=I[0];}
+		i0 -= g.offset;
+		i1 -= g.offset;
+		if(g.symmetry<0)
+			{
+			if(i0==i1) {*sign=0; return -1;}
+			return i1*(i1-1)/2+i0;
+			}
+		else
+			{
+			return i1*(i1+1)/2+i0;
+			}
+		}
+		break;
+
+	default: //general case
+		{
+		*sign=1;
+
+                if(g.symmetry==0) //rectangular case
+			{
+			LA_largeindex r=0;
+			for(int i=I.size()-1; i>=0; --i)
+				{
+				r*= g.range;
+				r+= I[i]-g.offset;
+				}
+			return r;
+			}
+		}
+
+		//compressed storage case
+		NRVec<LA_index> II(I);
+		II.copyonwrite();
+		II -= g.offset;
+		int parity=netsort(II.size(),&II[0]);
+		if(g.symmetry<0 && (parity&1)) *sign= -1;
+		if(g.symmetry<0) //antisymmetric
+			{
+			for(int i=0; i<I.size()-1; ++i) 
+				if(II[i]==II[i+1])
+					{*sign=0; return -1;} //identical indices of antisymmetric tensor
+
+			LA_largeindex r=0;
+                        for(int i=0; i<II.size(); ++i) r += simplicial(i+1,II[i]-i);
+                        return r;
+			}
+		else	//symmetric
+			{
+			LA_largeindex r=0;
+			for(int i=0; i<II.size(); ++i) r += simplicial(i+1,II[i]);
+			return r;
+			}
+		break;
+	}
+laerror("this error should not happen");
+return -1;
+}
+
+
+
+
 template<typename T>
-LA_largeindex Tensor<T>::index(int *sign, const SUPERINDEX &I)
+LA_largeindex Tensor<T>::index(int *sign, const SUPERINDEX &I) const
 {
 //check index structure and ranges
 #ifdef DEBUG
@@ -45,11 +131,27 @@ for(int i=0; i<I.size(); ++i)
 	}
 #endif
 
-
-//@@@@@@@@@
+LA_largeindex r=0;
+*sign=1;
+for(int g=0; g<shape.size(); ++g) //loop over index groups
+	{
+	int gsign;
+	LA_largeindex groupindex =  subindex(&gsign,shape[g],I[g]);
+	std::cout <<"INDEX TEST group "<<g<<" cumsizes "<< cumsizes[g]<<" groupindex "<<groupindex<<std::endl;
+	*sign *= gsign;
+	if(groupindex == -1) return -1;
+	r += groupindex * cumsizes[g];
+	}
+return r;
 }
 
+//@@@@todo flatindex
 
+//@@@@todo vindex
+
+
+template class Tensor<double>;
+template class Tensor<std::complex<double> >;
 
 
 }//namespace