Chris@49: #include <iostream>
Chris@49: 
Chris@49: #include "armadillo"
Chris@49: 
Chris@49: using namespace arma;
Chris@49: using namespace std;
Chris@49: 
Chris@49: 
Chris@49: int main(int argc, char** argv)
Chris@49:   {
Chris@49:   cout << "Armadillo version: " << arma_version::as_string() << endl;
Chris@49:   
Chris@49:   // directly specify the matrix size (elements are uninitialised)
Chris@49:   mat A(2,3);
Chris@49:   
Chris@49:   // .n_rows = number of rows    (read only)
Chris@49:   // .n_cols = number of columns (read only)
Chris@49:   cout << "A.n_rows = " << A.n_rows << endl;
Chris@49:   cout << "A.n_cols = " << A.n_cols << endl;
Chris@49:   
Chris@49:   // directly access an element (indexing starts at 0)
Chris@49:   A(1,2) = 456.0;
Chris@49:   
Chris@49:   A.print("A:");
Chris@49:   
Chris@49:   // scalars are treated as a 1x1 matrix,
Chris@49:   // hence the code below will set A to have a size of 1x1
Chris@49:   A = 5.0;
Chris@49:   A.print("A:");
Chris@49:   
Chris@49:   // if you want a matrix with all elements set to a particular value
Chris@49:   // the .fill() member function can be used
Chris@49:   A.set_size(3,3);
Chris@49:   A.fill(5.0);
Chris@49:   A.print("A:");
Chris@49:   
Chris@49:   
Chris@49:   mat B;
Chris@49:   
Chris@49:   // endr indicates "end of row"
Chris@49:   B << 0.555950 << 0.274690 << 0.540605 << 0.798938 << endr
Chris@49:     << 0.108929 << 0.830123 << 0.891726 << 0.895283 << endr
Chris@49:     << 0.948014 << 0.973234 << 0.216504 << 0.883152 << endr
Chris@49:     << 0.023787 << 0.675382 << 0.231751 << 0.450332 << endr;
Chris@49:   
Chris@49:   // print to the cout stream
Chris@49:   // with an optional string before the contents of the matrix
Chris@49:   B.print("B:");
Chris@49:   
Chris@49:   // the << operator can also be used to print the matrix
Chris@49:   // to an arbitrary stream (cout in this case) 
Chris@49:   cout << "B:" << endl << B << endl;
Chris@49:   
Chris@49:   // save to disk
Chris@49:   B.save("B.txt", raw_ascii);
Chris@49:   
Chris@49:   // load from disk
Chris@49:   mat C;
Chris@49:   C.load("B.txt");
Chris@49:   
Chris@49:   C += 2.0 * B;
Chris@49:   C.print("C:");
Chris@49:   
Chris@49:   
Chris@49:   // submatrix types:
Chris@49:   //
Chris@49:   // .submat(first_row, first_column, last_row, last_column)
Chris@49:   // .row(row_number)
Chris@49:   // .col(column_number)
Chris@49:   // .cols(first_column, last_column)
Chris@49:   // .rows(first_row, last_row)
Chris@49:   
Chris@49:   cout << "C.submat(0,0,3,1) =" << endl;
Chris@49:   cout << C.submat(0,0,3,1) << endl;
Chris@49:   
Chris@49:   // generate the identity matrix
Chris@49:   mat D = eye<mat>(4,4);
Chris@49:   
Chris@49:   D.submat(0,0,3,1) = C.cols(1,2);
Chris@49:   D.print("D:");
Chris@49:   
Chris@49:   // transpose
Chris@49:   cout << "trans(B) =" << endl;
Chris@49:   cout << trans(B) << endl;
Chris@49:   
Chris@49:   // maximum from each column (traverse along rows)
Chris@49:   cout << "max(B) =" << endl;
Chris@49:   cout << max(B) << endl;
Chris@49:   
Chris@49:   // maximum from each row (traverse along columns)
Chris@49:   cout << "max(B,1) =" << endl;
Chris@49:   cout << max(B,1) << endl;
Chris@49:   
Chris@49:   // maximum value in B
Chris@49:   cout << "max(max(B)) = " << max(max(B)) << endl;
Chris@49:   
Chris@49:   // sum of each column (traverse along rows)
Chris@49:   cout << "sum(B) =" << endl;
Chris@49:   cout << sum(B) << endl;
Chris@49:   
Chris@49:   // sum of each row (traverse along columns)
Chris@49:   cout << "sum(B,1) =" << endl;
Chris@49:   cout << sum(B,1) << endl;
Chris@49:   
Chris@49:   // sum of all elements
Chris@49:   cout << "sum(sum(B)) = " << sum(sum(B)) << endl;
Chris@49:   cout << "accu(B)     = " << accu(B) << endl;
Chris@49:   
Chris@49:   // trace = sum along diagonal
Chris@49:   cout << "trace(B)    = " << trace(B) << endl;
Chris@49:   
Chris@49:   // random matrix -- values are uniformly distributed in the [0,1] interval
Chris@49:   mat E = randu<mat>(4,4);
Chris@49:   E.print("E:");
Chris@49:   
Chris@49:   cout << endl;
Chris@49:   
Chris@49:   // row vectors are treated like a matrix with one row
Chris@49:   rowvec r;
Chris@49:   r << 0.59499 << 0.88807 << 0.88532 << 0.19968;
Chris@49:   r.print("r:");
Chris@49:   
Chris@49:   // column vectors are treated like a matrix with one column
Chris@49:   colvec q;
Chris@49:   q << 0.81114 << 0.06256 << 0.95989 << 0.73628;
Chris@49:   q.print("q:");
Chris@49:   
Chris@49:   // dot or inner product
Chris@49:   cout << "as_scalar(r*q) = " << as_scalar(r*q) << endl;
Chris@49:   
Chris@49:   
Chris@49:   // outer product
Chris@49:   cout << "q*r =" << endl;
Chris@49:   cout << q*r << endl;
Chris@49:   
Chris@49:   // multiply-and-accumulate operation
Chris@49:   // (no temporary matrices are created)
Chris@49:   cout << "accu(B % C) = " << accu(B % C) << endl;
Chris@49:   
Chris@49:   // sum of three matrices (no temporary matrices are created)
Chris@49:   mat F = B + C + D;
Chris@49:   F.print("F:");
Chris@49:   
Chris@49:   // imat specifies an integer matrix
Chris@49:   imat AA;
Chris@49:   imat BB;
Chris@49:   
Chris@49:   AA << 1 << 2 << 3 << endr << 4 << 5 << 6 << endr << 7 << 8 << 9;
Chris@49:   BB << 3 << 2 << 1 << endr << 6 << 5 << 4 << endr << 9 << 8 << 7;
Chris@49:   
Chris@49:   // comparison of matrices (element-wise)
Chris@49:   // output of a relational operator is a umat
Chris@49:   umat ZZ = (AA >= BB);
Chris@49:   ZZ.print("ZZ =");
Chris@49:   
Chris@49:   
Chris@49:   // 2D field of arbitrary length row vectors
Chris@49:   // (fields can also store abitrary objects, e.g. instances of std::string)
Chris@49:   field<rowvec> xyz(3,2);
Chris@49:   
Chris@49:   xyz(0,0) = randu(1,2);
Chris@49:   xyz(1,0) = randu(1,3);
Chris@49:   xyz(2,0) = randu(1,4);
Chris@49:   xyz(0,1) = randu(1,5);
Chris@49:   xyz(1,1) = randu(1,6);
Chris@49:   xyz(2,1) = randu(1,7);
Chris@49:   
Chris@49:   cout << "xyz:" << endl;
Chris@49:   cout << xyz << endl;
Chris@49:   
Chris@49:   
Chris@49:   // cubes ("3D matrices")
Chris@49:   cube Q( B.n_rows, B.n_cols, 2 );
Chris@49:   
Chris@49:   Q.slice(0) = B;
Chris@49:   Q.slice(1) = 2.0 * B;
Chris@49:   
Chris@49:   Q.print("Q:");
Chris@49:   
Chris@49:   
Chris@49:   return 0;
Chris@49:   }
Chris@49: