/// <summary>
/// Subtracts a function from the polynomial.
/// <para>
/// If the function is not a <seealso cref="RealPolynomialFunction1D"/> then the subtract takes place
/// as in <seealso cref="DoubleFunction1D"/>, otherwise the result will also be a polynomial.
///
/// </para>
/// </summary>
/// <param name="f"> the function to subtract </param>
/// <returns> $P-f$ </returns>
public override DoubleFunction1D subtract(DoubleFunction1D f)
{
ArgChecker.notNull(f, "function");
if (f is RealPolynomialFunction1D)
{
RealPolynomialFunction1D p1 = (RealPolynomialFunction1D)f;
double[] c = _coefficients;
double[] c1 = p1.Coefficients;
int m = c.Length;
int n = c1.Length;
int min = Math.Min(m, n);
int max = Math.Max(m, n);
double[] c3 = new double[max];
for (int i = 0; i < min; i++)
{
c3[i] = c[i] - c1[i];
}
for (int i = min; i < max; i++)
{
if (m == max)
{
c3[i] = c[i];
}
else
{
c3[i] = -c1[i];
}
}
return(new RealPolynomialFunction1D(c3));
}
return(DoubleFunction1D.this.subtract(f));
}
/// <summary>
/// Adds a function to the polynomial.
/// If the function is not a <seealso cref="RealPolynomialFunction1D"/> then the addition takes
/// place as in <seealso cref="DoubleFunction1D"/>, otherwise the result will also be a polynomial.
/// </summary>
/// <param name="f"> the function to add </param>
/// <returns> $P+f$ </returns>
public override DoubleFunction1D add(DoubleFunction1D f)
{
ArgChecker.notNull(f, "function");
if (f is RealPolynomialFunction1D)
{
RealPolynomialFunction1D p1 = (RealPolynomialFunction1D)f;
double[] c1 = p1.Coefficients;
double[] c = _coefficients;
int n = c1.Length;
bool longestIsNew = n > _n;
double[] c3 = longestIsNew ? Arrays.copyOf(c1, n) : Arrays.copyOf(c, _n);
for (int i = 0; i < (longestIsNew ? _n : n); i++)
{
c3[i] += longestIsNew ? c[i] : c1[i];
}
return(new RealPolynomialFunction1D(c3));
}
return(DoubleFunction1D.this.add(f));
}
//-------------------------------------------------------------------------
public override bool Equals(object obj)
{
if (this == obj)
{
return(true);
}
if (obj == null)
{
return(false);
}
if (this.GetType() != obj.GetType())
{
return(false);
}
RealPolynomialFunction1D other = (RealPolynomialFunction1D)obj;
if (!Arrays.Equals(_coefficients, other._coefficients))
{
return(false);
}
return(true);
}
/// <summary>
/// Multiplies the polynomial by a function.
/// If the function is not a <seealso cref="RealPolynomialFunction1D"/> then the multiplication takes
/// place as in <seealso cref="DoubleFunction1D"/>, otherwise the result will also be a polynomial.
/// </summary>
/// <param name="f"> the function by which to multiply </param>
/// <returns> $P \dot f$ </returns>
public override DoubleFunction1D multiply(DoubleFunction1D f)
{
ArgChecker.notNull(f, "function");
if (f is RealPolynomialFunction1D)
{
RealPolynomialFunction1D p1 = (RealPolynomialFunction1D)f;
double[] c = _coefficients;
double[] c1 = p1.Coefficients;
int m = c1.Length;
double[] newC = new double[_n + m - 1];
for (int i = 0; i < newC.Length; i++)
{
newC[i] = 0;
for (int j = Math.Max(0, i + 1 - m); j < Math.Min(_n, i + 1); j++)
{
newC[i] += c[j] * c1[i - j];
}
}
return(new RealPolynomialFunction1D(newC));
}
return(DoubleFunction1D.this.multiply(f));
}