ParaMonte Fortran 2.0.0 Parallel Monte Carlo and Machine Learning LibrarySee the latest version documentation.

Generate and return a scalar (or a vector of length size or an array of the same shape as the input p) containing the odds of getting a head in a single (or a series) of coin-flipping experiment(s).
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## Detailed Description

Generate and return a scalar (or a vector of length size or an array of the same shape as the input p) containing the odds of getting a head in a single (or a series) of coin-flipping experiment(s).

The coin can be optionally biased toward getting a head (.true.) with the input user-specified probability p.

Parameters
 [in] p : The input scalar or array of arbitrary rank of type real of kind any supported by the processor (e.g., RK, RK32, RK64, or RK128) within the range [0, 1], representing the probability of success/yes/true (or getting head in a coin-flip). A value other than p = 0.5 corresponds to a biased coin-flip experiment. If the input argument size is present, then p must be a scalar. If the input argument size is missing, then p can be a scalar or array of arbitrary rank and shape. (optional, default = 0.5) [in] size : The input scalar of type integer of default kind IK, representing the size of the output rand vector. (optional, if present, then p must be a scalar and the output will be a vector.)
Returns
rand : The output scalar or vector of length size, or array of the same shape as the input p of type logical of default kind LK, containing the Bernoulli-distributed random output value.

Possible calling interfaces

rand = isHead() ! single fair-coin flipping.
rand = isHead(p) ! elemental coin-flipping with p as the odds of success.
rand(1:size) = isHead(p, size) ! non-elemental coin-flipping of size times with p as the odds of success.
!
Generate and return a scalar (or a vector of length size or an array of the same shape as the input p...
This module contains classes and procedures for generating Bernoulli-distributed random numbers.
Definition: pm_distBern.F90:39
Warning
The input value for p must be a number between 0 and 1.
This condition is verified only if the library is built with the preprocessor macro CHECK_ENABLED=1.
Keep in mind that the interface isHead() uses a default single-precision value p = .5.
On the current hardware technology, this corresponds to a 32-bit real precision.
This implies a repeat cycle of $$\sim10^6$$ for the generated random numbers.
If more random numbers are needed, specify the value p = .5_RKG, where RKG refers to a higher real precision kind capable of generating the desired number of random coin-flipping.
Remarks
The procedures under discussion are impure.
The procedures under this generic interface are elemental when p is present and the size argument is missing.
Note
The procedure isHead() without any input arguments is equivalent to getUnifRand() without any input arguments.
getBernRand
setBernRand
getUnifRand
setUnifRand

Example usage

1program example
2
3 use pm_kind, only: SK, IK, LK
4 use pm_kind, only: RK, RKS, RKD, RKH
5 use pm_io, only: display_type
7
8 implicit none
9
10 type(display_type) :: disp
11
12 disp = display_type(file = "main.out.F90")
13
14 call disp%skip()
15 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")
16 call disp%show("! Flip a potentially biased coin (as determined by the success rate p).")
17 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")
18 call disp%skip()
19
20 call disp%show("isHead() ! flip a fair coin.")
22 call disp%skip()
23
24 call disp%show("isHead(size = 5_IK) ! flip a fair coin 5 times.")
25 call disp%show( isHead(size = 5_IK) )
26 call disp%skip()
27
28 call disp%show("isHead(p = 0.5_RKS) ! flip a fair coin with real-32bit precision.")
29 call disp%show( isHead(p = 0.5_RKS) )
30 call disp%skip()
31
32 call disp%show("isHead(p = 0.5_RKD) ! flip a fair coin with real-64bit precision.")
33 call disp%show( isHead(p = 0.5_RKD) )
34 call disp%skip()
35
36 call disp%show("isHead(p = 0.5_RKH) ! flip a fair coin with real-128bit precision.")
37 call disp%show( isHead(p = 0.5_RKH) )
38 call disp%skip()
39
40 call disp%show("isHead(0.25) ! flip an unfair coin with 0.25 odds of success.")
42 call disp%skip()
43
44 call disp%show("isHead(0.25, size = 5_IK) ! flip an unfair coin with 0.25 odds of success 5 times.")
45 call disp%show( isHead(0.25, size = 5_IK) )
46 call disp%skip()
47
48 call disp%show("isHead(p = [0.05, 0.25, 0.75, 0.95]) ! flip four different unfair coins.")
49 call disp%show( isHead(p = [0.05, 0.25, 0.75, 0.95]) )
50 call disp%skip()
51
52end program example
This is a generic method of the derived type display_type with pass attribute.
Definition: pm_io.F90:11726
This is a generic method of the derived type display_type with pass attribute.
Definition: pm_io.F90:11508
This module contains classes and procedures for input/output (IO) or generic display operations on st...
Definition: pm_io.F90:252
type(display_type) disp
This is a scalar module variable an object of type display_type for general display.
Definition: pm_io.F90:11393
This module defines the relevant Fortran kind type-parameters frequently used in the ParaMonte librar...
Definition: pm_kind.F90:268
integer, parameter RK
The default real kind in the ParaMonte library: real64 in Fortran, c_double in C-Fortran Interoperati...
Definition: pm_kind.F90:543
integer, parameter LK
The default logical kind in the ParaMonte library: kind(.true.) in Fortran, kind(....
Definition: pm_kind.F90:541
integer, parameter IK
The default integer kind in the ParaMonte library: int32 in Fortran, c_int32_t in C-Fortran Interoper...
Definition: pm_kind.F90:540
integer, parameter RKD
The double precision real kind in Fortran mode. On most platforms, this is an 64-bit real kind.
Definition: pm_kind.F90:568
integer, parameter SK
The default character kind in the ParaMonte library: kind("a") in Fortran, c_char in C-Fortran Intero...
Definition: pm_kind.F90:539
integer, parameter RKH
The scalar integer constant of intrinsic default kind, representing the highest-precision real kind t...
Definition: pm_kind.F90:858
integer, parameter RKS
The single-precision real kind in Fortran mode. On most platforms, this is an 32-bit real kind.
Definition: pm_kind.F90:567
Generate and return an object of type display_type.
Definition: pm_io.F90:10282

Example Unix compile command via Intel ifort compiler
1#!/usr/bin/env sh
2rm main.exe
3ifort -fpp -standard-semantics -O3 -Wl,-rpath,../../../lib -I../../../inc main.F90 ../../../lib/libparamonte* -o main.exe
4./main.exe

Example Windows Batch compile command via Intel ifort compiler
1del main.exe
2set PATH=..\..\..\lib;%PATH%
3ifort /fpp /standard-semantics /O3 /I:..\..\..\include main.F90 ..\..\..\lib\libparamonte*.lib /exe:main.exe
4main.exe

Example Unix / MinGW compile command via GNU gfortran compiler
1#!/usr/bin/env sh
2rm main.exe
3gfortran -cpp -ffree-line-length-none -O3 -Wl,-rpath,../../../lib -I../../../inc main.F90 ../../../lib/libparamonte* -o main.exe
4./main.exe

Example output
1
2!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3! Flip a potentially biased coin (as determined by the success rate p).
4!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
5
6isHead() ! flip a fair coin.
7F
8
9isHead(size = 5_IK) ! flip a fair coin 5 times.
10F, F, T, T, T
11
12isHead(p = 0.5_RKS) ! flip a fair coin with real-32bit precision.
13T
14
15isHead(p = 0.5_RKD) ! flip a fair coin with real-64bit precision.
16F
17
18isHead(p = 0.5_RKH) ! flip a fair coin with real-128bit precision.
19F
20
21isHead(0.25) ! flip an unfair coin with 0.25 odds of success.
22F
23
24isHead(0.25, size = 5_IK) ! flip an unfair coin with 0.25 odds of success 5 times.
25F, T, F, F, F
26
27isHead(p = [0.05, 0.25, 0.75, 0.95]) ! flip four different unfair coins.
28F, F, T, T
29
30
Test:
test_pm_distBern

Final Remarks

If you believe this algorithm or its documentation can be improved, we appreciate your contribution and help to edit this page's documentation and source file on GitHub.

1. If you use any parts or concepts from this library to any extent, please acknowledge the usage by citing the relevant publications of the ParaMonte library.
2. If you regenerate any parts/ideas from this library in a programming environment other than those currently supported by this ParaMonte library (i.e., other than C, C++, Fortran, MATLAB, Python, R), please also ask the end users to cite this original ParaMonte library.

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Help us justify its continued development and maintenance by acknowledging its benefit to society, distributing it, and contributing to it.

Author:
Amir Shahmoradi, Oct 16, 2009, 11:14 AM, Michigan

Definition at line 160 of file pm_distBern.F90.

The documentation for this interface was generated from the following file: