Overview

Table of Contents

• Motivating example
• Where to start?

‍This is the homepage of TRIQS/nda v1.3.0. The source code can be found on GitHub.

nda is a C++ library providing an efficient and flexible multi-dimensional array class. It is an essential building-block of the TRIQS project.

Some features include

• coded in C++17/20 using concepts
• expressions are implemented lazily for maximum performance
• flexible and lightweight view types
• matrix and vector class with BLAS/LAPACK backend
• easily store and retrieve arrays to and from HDF5 files using TRIQS/h5
• common MPI functionality using TRIQS/mpi
• Python bindings
• GPU and CUDA support
• and more.

Motivating example

#include <nda/nda.hpp>
#include <nda/h5.hpp>
 
#include <h5/h5.hpp>
 
int main() {
  // create an array of shape (4,4,4)
  nda::array<long, 3> A(4, 4, 4);
 
  // create an array given its data
  nda::array<long, 2> B{{1, 2}, {3, 4}, {5, 6}};
 
  // assign a scalar to the full array or a single element
  A() = 0;
  A(0, 1, 2) = 40;
 
  // access single elements
  int a = A(0, 1, 2) + B(0, 1);
 
  // access a slice of the array of shape (3, 2)
  auto V = A(range(0, 3), range(0, 2), 0);
 
  // lazy arithmetic operations
  auto C = V + 2 * B; // C is an expression
  auto D = nda::make_regular(C); // D is an array
 
  // various algorithms
  min_element(V);
  max_element(V);
  sum(V);
 
  // write to HDF5 file
  {
    h5::file file("dat.h5", 'w');
    h5::write(file, "A", A);
  }
 
  // read from HDF5 file
  array<long, 3> D;
  {
    h5::file file("dat.h5", 'r');
    h::read(file, "A", D);
  }
}

Where to start?

The Installation section tells you how to get the library and make it available on your system.

Integration in C++ projects explains how to integrate nda in your own C++ code.

Then, you can start with the Examples section to get an overview of the library's features and how nda can be used in practice.

Furthermore, we provide a detailed reference API Documentation to answer your questions.

If you experience any problem with the library, you can post an Issue on GitHub.