nag_rand_hypergeometric (g05tec) generates
integers
from a discrete hypergeometric distribution, where the probability of
is
The variates can be generated with or without using a search table and index. If a search table is used then it is stored with the index in a reference vector and subsequent calls to nag_rand_hypergeometric (g05tec) with the same parameter values can then use this reference vector to generate further variates. The reference array is generated by a recurrence relation if , otherwise Stirling's approximation is used.
One of the initialization functions
nag_rand_init_repeatable (g05kfc) (for a repeatable sequence if computed sequentially) or
nag_rand_init_nonrepeatable (g05kgc) (for a non-repeatable sequence) must be called prior to the first call to
nag_rand_hypergeometric (g05tec).
- 1:
– Nag_ModeRNGInput
-
On entry: a code for selecting the operation to be performed by the function.
- Set up reference vector only.
- Generate variates using reference vector set up in a prior call to nag_rand_hypergeometric (g05tec).
- Set up reference vector and generate variates.
- Generate variates without using the reference vector.
Constraint:
, , or .
- 2:
– IntegerInput
-
On entry: , the number of pseudorandom numbers to be generated.
Constraint:
.
- 3:
– IntegerInput
-
On entry: , the sample size of the hypergeometric distribution.
Constraint:
.
- 4:
– IntegerInput
-
On entry: , the population size of the hypergeometric distribution.
Constraint:
.
- 5:
– IntegerInput
-
On entry: , the number of specified items of the hypergeometric distribution.
Constraint:
.
- 6:
– doubleCommunication Array
-
On entry: if
, the reference vector from the previous call to
nag_rand_hypergeometric (g05tec).
If
,
r is not referenced and may be
NULL.
On exit: if , the reference vector.
- 7:
– IntegerInput
-
On entry: the dimension of the array
r.
Suggested values:
- if , approximately;
- otherwise .
Constraints:
- if or , lr must not be too small, but the limit is too complicated to specify;
- if , lr must remain unchanged from the previous call to nag_rand_hypergeometric (g05tec).
- 8:
– IntegerCommunication Array
-
Note: the dimension,
, of this array is dictated by the requirements of associated functions that must have been previously called. This array MUST be the same array passed as argument
state in the previous call to
nag_rand_init_repeatable (g05kfc) or
nag_rand_init_nonrepeatable (g05kgc).
On entry: contains information on the selected base generator and its current state.
On exit: contains updated information on the state of the generator.
- 9:
– IntegerOutput
-
On exit: the pseudorandom numbers from the specified hypergeometric distribution.
- 10:
– NagError *Input/Output
-
The NAG error argument (see
Section 3.7 in How to Use the NAG Library and its Documentation).
Not applicable.
Please consult the
x06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this function. Please also consult the
Users' Note for your implementation for any additional implementation-specific information.
None.
The example program prints
pseudorandom integers from a hypergeometric distribution with
,
and
, generated by a single call to
nag_rand_hypergeometric (g05tec), after initialization by
nag_rand_init_repeatable (g05kfc).
None.