9.11 User-Defined Type Example

FILENAME: exampl10.cpp

/*

 * This example shows how to use a user-defined type.
 * The number class information is stored in rational.h and
 * and rational.cpp. The Rational class is complete, but not
 * designed for optimal efficiency. It is included for example
 * purposes only.
 */

//   Include the RWGenFact<T> class header file.
#include <rw/math/genfact.h>
// Include the matrix and vector header files:
#include <rw/math/genmat.h>
#include <rw/math/mathvec.h>
#include <rw/rstream.h>
// Include the user-defined type Rational:
#include "rational.h"

// Initial data for the vectors:
const Rational adata[] = {
      Rational(-3), Rational(2), Rational(1), 
      Rational(8), Rational(-7), Rational(9), 
      Rational(5), Rational(4), Rational(-6)};
const Rational arhs[]   = {
      Rational(6), Rational(9), Rational(1)};

main()
{
   // Construct a test matrix and print it out:
   RWGenMat<Rational> testmat(adata,3,3);
   cout << "test matrix:\n" << testmat << "\n";

   /*
    * Calculate and print the inverse.
    * Note that a type conversion occurs:
    * testmat is converted to type RWGenFact<Rational>
    * before the inverse is computed.
    */
   cout << "inverse:\n" << inverse(testmat);

   // Now construct a RWGenFact<Rational> from the matrix:
   RWGenFact<Rational> LUtest(testmat);

   // Once constructed, LUtest may be reused as required:

   // Find the determinant:
   cout << "\ndeterminant\n" << determinant(LUtest) << endl;

   // Solve the linear system testmat*x = rhs:
   RWMathVec<Rational> rhs(arhs, 3);
   RWMathVec<Rational> x = solve(LUtest, rhs);

   cout << "solution:\n" << x << "\n";
   return 0;
}

Sample Input:

None required.

Sample Output:

test matrix:
3x3 [
-3/1 8/1 5/1
2/1 -7/1 4/1
1/1 9/1 -6/1
]
inverse:
3x3 [
6/235 93/235 67/235
16/235 13/235 22/235
5/47 7/47 1/47
]
determinant
235/1
solution:
[
4/1 1/1 2/1
]

Note: compare these values with the results of the example in Section 9.8, "Linear Algebra Example."