public static void main( String args[] ) { Polynomial a = Polynomial.wrap(5,-2,3,0.5,30.4); Polynomial b = Polynomial.wrap(-0.4,8.4,-2.3); System.out.println("a = "+a); System.out.println("b = "+b); System.out.println("a + b = "+PolynomialOps.add(a,b,null)); System.out.println("a * b = "+PolynomialOps.multiply(a, b, null)); // Declare storage for the quotient and the remainder Polynomial q = new Polynomial(10); Polynomial r = new Polynomial(10); PolynomialOps.divide(a, b, q,r); System.out.println("a / b = ( "+q+" , "+r+" )"); System.out.println("Derivative a = "+PolynomialOps.derivative(a,null)); } }
/** * Compute the sturm sequence using a straight forward method */ private List<Double> computeSturm( Polynomial poly , double x ) { Polynomial d = new Polynomial(poly.size); PolynomialOps.derivative(poly, d); List<Double> found = new ArrayList<Double>(); found.add( poly.evaluate(x)); found.add( d.evaluate(x)); Polynomial q = new Polynomial(poly.size); Polynomial r = new Polynomial(poly.size); Polynomial p1 = new Polynomial(poly.size); Polynomial p2 = new Polynomial(poly.size); p1.setTo(poly); p2.setTo(d); do { PolynomialOps.divide(p1,p2,q,r); for( int i = 0; i < r.size; i++ ) { r.c[i] = -r.c[i]; } found.add(r.evaluate(x)); p1.setTo(p2); p2.setTo(r); } while( r.computeDegree() > 0 ); return found; }
/** * Randomly generate polynomials. First divide then multiply them back together to reconstruct * the original. */ @Test public void divide_then_multiply() { for( int i = 2; i < 10; i++ ) { Polynomial n = createRandom(i); for( int j = 1; j < i; j++ ) { Polynomial d = createRandom(j); Polynomial q = new Polynomial(10); Polynomial r = new Polynomial(10); PolynomialOps.divide(n,d,q,r); Polynomial a = PolynomialOps.multiply(d,q,null); Polynomial b = PolynomialOps.add(a,r,null); assertTrue(b.isIdentical(n, 1e-8)); } } }
@Test public void divide() { // numerator and denominator, intentionally add trailing zeros to skew things up Polynomial n = Polynomial.wrap(1,2,3,0); Polynomial d = Polynomial.wrap(-3,1,0); // quotient and remainder Polynomial q = new Polynomial(10); Polynomial r = new Polynomial(10); // expected solutions Polynomial expectedQ = Polynomial.wrap(11,3,0); Polynomial expectedR = Polynomial.wrap(34); PolynomialOps.divide(n,d,q,r); assertEquals(3,q.size); assertEquals(1,r.size); assertTrue(expectedQ.isIdentical(q, 1e-8)); assertTrue(expectedR.isIdentical(r, 1e-8)); }