28 Numerics library [numerics]

28.5 Random number generation [rand]

28.5.3 Requirements [rand.req]

28.5.3.6 Random number distribution requirements [rand.req.dist]

Table 97: Random number distribution requirements [tab:rand.req.dist]

🔗	Expression	Return type	Pre/post-condition	Complexity
🔗	D::result_type	T	T is an arithmetic type .	compile-time
🔗	D::param_type	P		compile-time
🔗	D()		Creates a distribution whose behavior is indistinguishable from that of any other newly default-constructed distribution of type D.	constant
🔗	D(p)		Creates a distribution whose behavior is indistinguishable from that of a distribution newly constructed directly from the values used to construct p.	same as p's construction
🔗	d.reset()	void	Subsequent uses of d do not depend on values produced by any engine prior to invoking reset.	constant
🔗	x.param()	P	Returns a value p such that D(p).param() == p.	no worse than the complexity of D(p)
🔗	d.param(p)	void	Postconditions: d.param() == p.	no worse than the complexity of D(p)
🔗	d(g)	T	With $p = d.param()$ , the sequence of numbers returned by successive invocations with the same object g is randomly distributed according to the associated p(z \|{p}) or $P (z_{i} \| {p})$ function.	amortized constant number of invocations of g
🔗	d(g,p)	T	The sequence of numbers returned by successive invocations with the same objects g and p is randomly distributed according to the associated p(z \|{p}) or $P (z_{i} \| {p})$ function.	amortized constant number of invocations of g
🔗	x.min()	T	Returns glb.	constant
🔗	x.max()	T	Returns lub.	constant
🔗	x == y	bool	This operator is an equivalence relation. Returns true if x.param() == y.param() and $S_{1} = S_{2}$ , where $S_{1}$ and $S_{2}$ are the infinite sequences of values that would be generated, respectively, by repeated future calls to x(g1) and y(g2) whenever g1 == g2. Otherwise returns false.	constant
🔗	x != y	bool	!(x == y).	same as x == y.
🔗	os << x	reference to the type of os	Writes to os a textual representation for the parameters and the additional internal data of x. Postconditions: The os.fmtflags and fill character are unchanged.
🔗	is >> d	reference to the type of is	Restores from is the parameters and additional internal data of the lvalue d. If bad input is encountered, ensures that d is unchanged by the operation and calls is.setstate(ios_base::failbit) (which may throw ios_base::failure ([iostate.flags])). Preconditions: is provides a textual representation that was previously written using an os whose imbued locale and whose type's template specialization arguments charT and traits were the same as those of is. Postconditions: The is.fmtflags are unchanged.