Asymptote has built-in versions of the standard libm mathematical
real(real) functions sin, cos, tan, asin,
acos, atan, exp, log, pow10,
log10, sinh, cosh, tanh, asinh,
acosh, atanh, sqrt, cbrt, fabs, expm1,
log1p, as well as the identity function identity.
Asymptote also defines the order n Bessel functions of
the first kind Jn(int n, real) and second kind
Yn(int n, real), as well as the gamma function gamma,
the error function erf, and the complementary error function
erfc. The standard real(real, real) functions atan2,
hypot, fmod, remainder are also included.
The functions degrees(real radians) and radians(real degrees)
can be used to convert between radians and degrees. The function
Degrees(real radians) returns the angle in degrees in the
interval [0,360).
For convenience, Asymptote defines variants Sin,
Cos, Tan, aSin, aCos, and aTan of
the standard trigonometric functions that use degrees rather than radians.
We also define complex versions of the sqrt, sin, cos,
exp, log, and gamma functions.
The functions floor, ceil, and round differ from
their usual definitions in that they all return an int value rather than
a real (since that is normally what one wants).
The functions Floor, Ceil, and Round are
respectively similar, except that if the result cannot be converted
to a valid int, they return intMax
for positive arguments and intMin for negative arguments,
rather than generating an integer overflow.
We also define a function sgn, which returns the sign of its
real argument as an integer (-1, 0, or 1).
There is an abs(int) function, as well as an abs(real)
function (equivalent to fabs(real)), an abs(pair) function
(equivalent to length(pair)).
Random numbers can be seeded with srand(int)
(for example, with srand(round((cputime().parent.clock%1)*1e9)))
and generated with
the int rand() function, which returns a random integer between 0
and the integer randMax. The unitrand() function returns
a random number uniformly distributed in the interval [0,1].
A Gaussian random number generator
Gaussrand and a collection of statistics routines, including
histogram, are provided in the module stats.
The functions factorial(int n), which returns n!, and
choose(int n, int k), which returns n!/(k!(n-k)!), are
also defined.
When configured with the GNU Scientific Library (GSL), available from
https://www.gnu.org/software/gsl/,
Asymptote contains an internal module gsl that
defines the airy functions Ai(real),
Bi(real), Ai_deriv(real), Bi_deriv(real),
zero_Ai(int), zero_Bi(int),
zero_Ai_deriv(int), zero_Bi_deriv(int), the Bessel functions
I(int, real), K(int, real), j(int, real),
y(int, real), i_scaled(int, real), k_scaled(int, real),
J(real, real), Y(real, real), I(real, real),
K(real, real), zero_J(real, int), the elliptic functions
F(real, real), E(real, real), and P(real, real),
the Jacobi elliptic functions real[] sncndn(real,real),
the exponential/trigonometric integrals Ei, Si, and Ci,
the Legendre polynomials Pl(int, real), and the Riemann zeta
function zeta(real). For example, to compute the sine integral
Si of 1.0:
import gsl; write(Si(1.0));
Asymptote also provides a few general purpose numerical routines:
real newton(int iterations=100, real f(real), real fprime(real), real x, bool verbose=false);Use Newton-Raphson iteration to solve for a root of a real-valued
differentiable function f, given its derivative fprime and
an initial guess x. Diagnostics for
each iteration are printed if verbose=true.
If the iteration fails after the maximum allowed number of loops
(iterations), realMax is returned.
real newton(int iterations=100, real f(real), real fprime(real), real x1, real x2, bool verbose=false);Use bracketed Newton-Raphson bisection to solve for a root of a real-valued
differentiable function f within an interval
[x1,x2] (on which the endpoint values of f have
opposite signs), given its derivative fprime. Diagnostics for
each iteration are printed if verbose=true.
If the iteration fails after the maximum allowed number of loops
(iterations), realMax is returned.
real simpson(real f(real), real a, real b, real acc=realEpsilon, real dxmax=b-a)returns the integral of f from a to b using adaptive Simpson integration.
Internally, operator init implicitly defines a constructor function
Person(string,string) as follows, where args is
string firstname, string lastname in this case:
struct Person {
string firstname;
string lastname;
static Person Person(args) {
Person p=new Person;
p.operator init(args);
return p;
}
}
which then can be used as:
Person joe=Person.Person("Joe", "Jones");
The following is also implicitly generated in the enclosing scope, after the end of the structure definition.
from Person unravel Person;
It allows us to use the constructor without qualification,
otherwise we would have to refer to the constructor by the qualified name
Person.Person.
cputime cputime()returns a structure cputime with cumulative CPU times
broken down into the fields parent.user, parent.system,
child.user, and child.system, along with the cumulative
wall clock time in parent.clock, all measured in seconds.
For convenience, the incremental fields change.user,
change.system, and change.clock indicate the change in
the corresponding fields since the last call to cputime(). The
function
void write(file file=stdout, string s="", cputime c,
string format=cputimeformat, suffix suffix=none);
displays the incremental user cputime followed by “u”, the incremental system cputime followed by “s”, the total user cputime followed by “U”, and the total system cputime followed by “S”.