From 8fa7194f2d060dd8dbf4f2b1464abc1df9bf2d3d Mon Sep 17 00:00:00 2001
From: Jiri Pittner <jiri@pittnerovi.com>
Date: Tue, 26 Mar 2024 17:49:09 +0100
Subject: [PATCH] working on tensor

---
 tensor.cc | 23 +++++++++++++++++++++++
 tensor.h  | 26 ++++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/tensor.cc b/tensor.cc
index a29d39b..1951334 100644
--- a/tensor.cc
+++ b/tensor.cc
@@ -23,6 +23,29 @@
 
 namespace LA {
 
+template<typename T>
+LA_largeindex Tensor<T>::index(const SUPERINDEX &I)
+{
+//check index structure and ranges
+#ifndef DEBUG
+if(I.size()!=shape.size()) laerror("mismatch in the number of tensor index groups");
+for(int i=0; i<I.size; ++i)
+	{
+	if(shape[i].number!=I[i].size()) {std::cerr<<"error in index group no. "<<i<<std::endl; laerror("mismatch in the size of tensor index group");}
+	for(int j=0; j<shape[i].number; ++j)
+		{
+		if(I[i][j] <shape[i].offset || I[i][j] >= shape[i].offset+shape[i].size()) 
+			{
+			std::cerr<<"error in index group no. "<<i<<" index no. "<<j<<std::endl;
+			laerror("tensor index out of range");
+			}
+		}
+	}
+#endif
+
+
+//@@@@@@@@@
+}
 
 
 
diff --git a/tensor.h b/tensor.h
index 7a908e2..a87382f 100644
--- a/tensor.h
+++ b/tensor.h
@@ -17,7 +17,7 @@
 */
 
 
-//a simple tensor class with arbitrary summetry of index subgroups
+//a simple tensor class with arbitrary symmetry of index subgroups
 //stored in an efficient way
 //presently only a rudimentary implementation
 //presently limited to 2G data size due to NRVec - maybe use a typedef LA_index 
@@ -28,6 +28,7 @@
 #define _TENSOR_H
 
 #include <stdint.h>
+#include <cstdarg>
 #include "vec.h"
 #include "miscfunc.h"
 
@@ -44,20 +45,41 @@ LA_index offset; //indices start at
 LA_index size;  //indices span this range
 } INDEXGROUP;
 
+typedef NRVec<LA_index> FLATINDEX; //all indices but in a single vector
+typedef NRVec<NRVec<LA_index> > SUPERINDEX; //all indices in the INDEXGROUP structure
+
+
 template<typename T>
 class Tensor {
 	NRVec<indexgroup> shape;
 	NRVec<T> data;	
 
+private:
+	LA_largeindex index(const SUPERINDEX &I); //map the tensor indices to the position in data
+	LA_largeindex index(const FLATINDEX &I); //map the tensor indices to the position in data
+	LA_largeindex vindex(int i1,va_list args); //map list of indices  to the position in data @@@must call va_end
+
 public:
 	Tensor() {};
 	Tensor(const NRVec<indexgroup> &s) : shape(s), data((int)size()) {data.clear();};
 	int rank() const; //is computed from shape
 	LA_largeindex size() const; //expensive, is computed from shape
 	void copyonwrite() {shape.copyonwrite(); data.copyonwrite();};
-	//@@@operator() lhs and rhs both via vararg a via superindex of flat and nested types, get/put to file, stream i/o
+	inline T& operator()(const SUPERINDEX &I) {return data[index(I)];};
+        inline const T& operator()(const SUPERINDEX &I) const  {return data[index(I)];}; 
+	inline T& operator()(const FLATINDEX &I) {return data[index(I)];};
+        inline const T& operator()(const FLATINDEX &I) const  {return data[index(I)];};
+	inline T& operator()(int i1...) {va_list args; va_start(args,i1); return data[vindex(i1,args)];};
+	inline const T& operator()(int i1...) const {va_list args; va_start(args,i1); return data[vindex(i1,args)];};
+
+	//@@@TODO - unwinding to full size in a specified index
+	//@@@TODO - contractions - basic and efficient
+	//@@@TODO get/put to file, stream i/o
 };
 
+
+
+
 template<typename T>
 int Tensor<T>:: rank() const
 {