{
debugmsg("numeric default constructor", LOGLEVEL_CONSTRUCT);
value = new cl_N;
- *value=cl_I(0);
+ *value = cl_I(0);
calchash();
- setflag(status_flags::evaluated|
+ setflag(status_flags::evaluated |
+ status_flags::expanded |
status_flags::hash_calculated);
}
{
debugmsg("numeric constructor from int",LOGLEVEL_CONSTRUCT);
// Not the whole int-range is available if we don't cast to long
- // first. This is due to the behaviour of the cl_I-ctor, which
+ // first. This is due to the behaviour of the cl_I-ctor, which
// emphasizes efficiency:
value = new cl_I((long) i);
calchash();
{
debugmsg("numeric constructor from uint",LOGLEVEL_CONSTRUCT);
// Not the whole uint-range is available if we don't cast to ulong
- // first. This is due to the behaviour of the cl_I-ctor, which
+ // first. This is due to the behaviour of the cl_I-ctor, which
// emphasizes efficiency:
value = new cl_I((unsigned long)i);
calchash();
case info_flags::negative:
return is_negative();
case info_flags::nonnegative:
- return compare(_num0())>=0;
+ return !is_negative();
case info_flags::posint:
return is_pos_integer();
case info_flags::negint:
- return is_integer() && (compare(_num0())<0);
+ return is_integer() && is_negative();
case info_flags::nonnegint:
return is_nonneg_integer();
case info_flags::even:
numeric numeric::power(const numeric & other) const
{
- static const numeric * _num1p=&_num1();
+ static const numeric * _num1p = &_num1();
if (&other==_num1p)
return *this;
if (::zerop(*value)) {
if (::zerop(*other.value))
throw (std::domain_error("numeric::eval(): pow(0,0) is undefined"));
- else if (other.is_real() && !::plusp(::realpart(*other.value)))
+ else if (::zerop(::realpart(*other.value)))
+ throw (std::domain_error("numeric::eval(): pow(0,I) is undefined"));
+ else if (::minusp(::realpart(*other.value)))
throw (std::overflow_error("numeric::eval(): division by zero"));
else
return _num0();
if (::zerop(*value)) {
if (::zerop(*other.value))
throw (std::domain_error("numeric::eval(): pow(0,0) is undefined"));
- else if (other.is_real() && !::plusp(::realpart(*other.value)))
+ else if (::zerop(::realpart(*other.value)))
+ throw (std::domain_error("numeric::eval(): pow(0,I) is undefined"));
+ else if (::minusp(::realpart(*other.value)))
throw (std::overflow_error("numeric::eval(): division by zero"));
else
return _num0();
}
/** Real part of a number. */
-numeric numeric::real(void) const
+const numeric numeric::real(void) const
{
return numeric(::realpart(*value)); // -> CLN
}
/** Imaginary part of a number. */
-numeric numeric::imag(void) const
+const numeric numeric::imag(void) const
{
return numeric(::imagpart(*value)); // -> CLN
}
* numerator of complex if real and imaginary part are both rational numbers
* (i.e numer(4/3+5/6*I) == 8+5*I), the number carrying the sign in all other
* cases. */
-numeric numeric::numer(void) const
+const numeric numeric::numer(void) const
{
if (this->is_integer()) {
return numeric(*this);
/** Denominator. Computes the denominator of rational numbers, common integer
* denominator of complex if real and imaginary part are both rational numbers
* (i.e denom(4/3+5/6*I) == 6), one in all other cases. */
-numeric numeric::denom(void) const
+const numeric numeric::denom(void) const
{
if (this->is_integer()) {
return _num1();
return _num0();
// Until somebody has the Blues and comes up with a much better idea and
// codes it (preferably in CLN) we make this a remembering function which
- // computes its results using the formula
+ // computes its results using the defining formula
// B(nn) == - 1/(nn+1) * sum_{k=0}^{nn-1}(binomial(nn+1,k)*B(k))
// whith B(0) == 1.
+ // Be warned, though: the Bernoulli numbers are probably computationally
+ // very expensive anyhow and you shouldn't expect miracles to happen.
static vector<numeric> results;
static int highest_result = -1;
int n = nn.sub(_num2()).div(_num2()).to_int();
* @exception range_error (argument must be an integer) */
const numeric fibonacci(const numeric & n)
{
- if (!n.is_integer()) {
+ if (!n.is_integer())
throw (std::range_error("numeric::fibonacci(): argument must be integer"));
- }
- // For positive arguments compute the nearest integer to
- // ((1+sqrt(5))/2)^n/sqrt(5). For negative arguments, apply an additional
- // sign. Note that we are falling back to longs, but this should suffice
- // for all times.
- int sig = 1;
- const long nn = ::abs(n.to_double());
- if (n.is_negative() && n.is_even())
- sig =-1;
+ // The following addition formula holds:
+ // F(n+m) = F(m-1)*F(n) + F(m)*F(n+1) for m >= 1, n >= 0.
+ // (Proof: For fixed m, the LHS and the RHS satisfy the same recurrence
+ // w.r.t. n, and the initial values (n=0, n=1) agree. Hence all values
+ // agree.)
+ // Replace m by m+1:
+ // F(n+m+1) = F(m)*F(n) + F(m+1)*F(n+1) for m >= 0, n >= 0
+ // Now put in m = n, to get
+ // F(2n) = (F(n+1)-F(n))*F(n) + F(n)*F(n+1) = F(n)*(2*F(n+1) - F(n))
+ // F(2n+1) = F(n)^2 + F(n+1)^2
+ // hence
+ // F(2n+2) = F(n+1)*(2*F(n) + F(n+1))
+ if (n.is_zero())
+ return _num0();
+ if (n.is_negative())
+ if (n.is_even())
+ return -fibonacci(-n);
+ else
+ return fibonacci(-n);
- // Need a precision of ((1+sqrt(5))/2)^-n.
- cl_float_format_t prec = ::cl_float_format((int)(0.208987641*nn+5));
- cl_R sqrt5 = ::sqrt(::cl_float(5,prec));
- cl_R phi = (1+sqrt5)/2;
- return numeric(::round1(::expt(phi,nn)/sqrt5)*sig);
+ cl_I u(0);
+ cl_I v(1);
+ cl_I m = The(cl_I)(*n.value) >> 1L; // floor(n/2);
+ for (uintL bit=::integer_length(m); bit>0; --bit) {
+ // Since a squaring is cheaper than a multiplication, better use
+ // three squarings instead of one multiplication and two squarings.
+ cl_I u2 = ::square(u);
+ cl_I v2 = ::square(v);
+ if (::logbitp(bit-1, m)) {
+ v = ::square(u + v) - u2;
+ u = u2 + v2;
+ } else {
+ u = v2 - ::square(v - u);
+ v = u2 + v2;
+ }
+ }
+ if (n.is_even())
+ // Here we don't use the squaring formula because one multiplication
+ // is cheaper than two squarings.
+ return u * ((v << 1) - u);
+ else
+ return ::square(u) + ::square(v);
}
git://www.ginac.de / ginac.git / blobdiff