annotate armadillo-2.4.4/examples/example2.cpp @ 0:8b6102e2a9b0

Armadillo Library

#include <iostream>

#include "armadillo"

using namespace arma;
using namespace std;


int main(int argc, char** argv)
  {
  cout << "Armadillo version: " << arma_version::as_string() << endl;
  
  mat A;
  
  A << 0.165300 << 0.454037 << 0.995795 << 0.124098 << 0.047084 << endr
    << 0.688782 << 0.036549 << 0.552848 << 0.937664 << 0.866401 << endr
    << 0.348740 << 0.479388 << 0.506228 << 0.145673 << 0.491547 << endr
    << 0.148678 << 0.682258 << 0.571154 << 0.874724 << 0.444632 << endr
    << 0.245726 << 0.595218 << 0.409327 << 0.367827 << 0.385736 << endr;
  
  A.print("A =");
  
  // determinant
  cout << "det(A) = " << det(A) << endl;
  
  // inverse
  cout << "inv(A) = " << endl << inv(A) << endl;
  
  
  //
  
  double k = 1.23;
  
  mat    B = randu<mat>(5,5);
  mat    C = randu<mat>(5,5);
  
  rowvec r = randu<rowvec>(5);
  colvec q = randu<colvec>(5);
  
  
  // examples of some expressions
  // for which optimised implementations exist
  
  // optimised implementation of a trinary expression
  // that results in a scalar
  cout << "as_scalar( r*inv(diagmat(B))*q ) = ";
  cout << as_scalar( r*inv(diagmat(B))*q ) << endl;
  
  // example of an expression which is optimised 
  // as a call to the dgemm() function in BLAS:
  cout << "k*trans(B)*C = " << endl << k*trans(B)*C;
  
  
  // If you want to see a trace of how Armadillo
  // evaluates expressions, compile with the
  // ARMA_EXTRA_DEBUG macro defined.
  // This was designed to work with the GCC compiler,
  // but it may also work with other compilers
  // if you have the Boost libraries installed
  // and told Armadillo to use them.
  // 
  // Example for GCC:
  // g++ example2.cpp -o example2 -larmadillo -DARMA_EXTRA_DEBUG
  // 
  // Running example2 will now produce a truckload of messages,
  // so you may want to redirect the output to a log file.
  
  return 0;
  }