Added examples of scripts

main/exciton_example.cpp

@@ -0,0 +1,140 @@
+#include <iostream>
+#include <fstream>
+#include <armadillo>
+#include <complex>
+#include <math.h>
+#include <stdlib.h>
+#include <string>
+#include <chrono>
+
+#include <xatu.hpp>
+
+#ifndef constants
+#define PI 3.141592653589793
+#define ec 1.6021766E-19
+#define eps0 8.8541878E-12
+#endif
+
+using namespace arma;
+using namespace std::chrono;
+
+int main(int argc, char* argv[]){
+
+    // Parse console stdin
+
+    if (argc != 2){
+		throw std::invalid_argument("Error: One input file is expected");
+	}
+    else if (argc < 2){
+        throw std::invalid_argument("Error: At least one input file is required (system config.)");
+    };
+
+    auto start = high_resolution_clock::now();
+
+    int nbands = 1;
+    int nrmbands = 0;
+    int ncell = 40;
+    arma::rowvec Q = {0., 0., 0.};
+
+    arma::rowvec parameters = {1., 1., 10.};
+    std::string modelfile = argv[1];    
+
+    int nstates = 8;
+
+    // ----------------- Model parameters & Output --------------------
+    bool writeEigvals = false;
+    std::string filename = "eigval.out";
+    FILE* textfile_en = fopen(filename.c_str(), "w");
+
+    bool writeStates = false;
+    std::string filename_st = "states.out";
+    FILE* textfile_st = fopen(filename_st.c_str(), "w");
+
+    bool writeWF = true;
+    std::string filename_kwf = "kwf.out";
+    FILE* textfile_kwf = fopen(filename_kwf.c_str(), "w");
+
+    bool writeRSWF = true;
+    std::string filename_rswf = "rswf.out";
+    FILE* textfile_rswf = fopen(filename_rswf.c_str(), "w");
+
+    // -------------------------- Main body ---------------------------
+
+    cout << "+---------------------------------------------------------------------------+" << endl;
+    cout << "|                                  Parameters                               |" << endl;
+    cout << "+---------------------------------------------------------------------------+" << endl;
+    cout << "N. cells: " << ncell*ncell << endl;
+    cout << "#bands: " << nbands << endl;
+    cout << "#removed bands: " << nrmbands << endl;
+    cout << "System configuration file: " << modelfile << "\n" << endl;
+
+    xatu::SystemConfiguration config = xatu::SystemConfiguration(modelfile);
+    xatu::Exciton bulkExciton = xatu::Exciton(config, ncell, nbands, nrmbands, parameters);
+    arma::cout << "Orbitals: " << bulkExciton.orbitals << arma::endl;
+    bulkExciton.setMode("realspace");
+
+    cout << "Valence bands:\n" << bulkExciton.valenceBands << endl;
+    cout << "Conduction bands:\n" << bulkExciton.conductionBands << endl;
+    cout << "Gauge used: " << bulkExciton.gauge << "\n" << endl;
+
+    cout << "+---------------------------------------------------------------------------+" << endl;
+    cout << "|                                Initialization                             |" << endl;
+    cout << "+---------------------------------------------------------------------------+" << endl;
+
+    bulkExciton.brillouinZoneMesh(ncell);
+    bulkExciton.initializeHamiltonian();
+    bulkExciton.BShamiltonian();
+    auto results = bulkExciton.diagonalize("diag", nstates);
+
+    cout << "+---------------------------------------------------------------------------+" << endl;
+    cout << "|                                    Results                                |" << endl;
+    cout << "+---------------------------------------------------------------------------+" << endl;
+
+    printEnergies(results, nstates, 6);
+
+    cout << "+---------------------------------------------------------------------------+" << endl;
+    cout << "|                                    Output                                 |" << endl;
+    cout << "+---------------------------------------------------------------------------+" << endl;
+
+    if(writeEigvals){
+        std::cout << "Writing eigvals to file: " << filename << std::endl;
+        fprintf(textfile_en, "%d\n", ncell);
+        results.writeEigenvalues(textfile_en, 8);
+    }
+
+    if(writeStates){
+        std::cout << "Writing states to file: " << filename_st << std::endl;
+        results.writeStates(textfile_st, nstates);
+    }
+
+    if(writeWF){
+        std::cout << "Writing k w.f. to file: " << filename_kwf << std::endl;
+        int nstates = 8;
+        for(int stateindex = 0; stateindex < nstates; stateindex++){
+            results.writeExtendedReciprocalAmplitude(stateindex, textfile_kwf);   
+        }
+    }
+
+    if(writeRSWF){
+        arma::uvec statesToWrite = arma::regspace<arma::uvec>(0, 7);
+        std::cout << "Writing real space w.f. to file: " << filename_rswf << std::endl;
+        arma::rowvec holeCell = {0., 0., 0.};
+        int holeIndex = 0;
+
+        for(unsigned int i = 0; i < statesToWrite.n_elem; i++){
+            std::cout << "Writing state " << i + 1 << " out of " << statesToWrite.n_elem << std::endl;
+            results.writeRealspaceAmplitude(statesToWrite(i), holeIndex, holeCell, textfile_rswf, 10);
+        }
+    }
+
+    fclose(textfile_en);
+    fclose(textfile_st);
+    fclose(textfile_kwf);
+    fclose(textfile_rswf);
+
+    auto stop = high_resolution_clock::now();
+    auto duration = duration_cast<milliseconds>(stop - start);
+    std::cout << "Elapsed time: " << duration.count()/1000.0 << " s" << std::endl;
+
+    return 0;
+};

main/minimal_example.cpp

@@ -0,0 +1,23 @@
+#include <armadillo>
+#include <xatu.hpp>
+
+using namespace xatu;
+
+int main(){
+
+    int nbands = 1;
+    int nrmbands = 0;
+    int ncell = 40;
+    arma::rowvec parameters = {1., 1., 10.};
+    int nstates = 8;
+
+    auto config = SystemConfiguration("./models/hBN.model");
+    auto exciton = Exciton(config, ncell, nbands, nrmbands, parameters);
+
+    exciton.brillouinZoneMesh(ncell);
+    exciton.initializeHamiltonian();
+    exciton.BShamiltonian();
+    auto results = exciton.diagonalize("diag", nstates);
+
+    return 0;
+};