Generate and return the (weighted) mean of an input sample of nsam observations with ndim = 1 or 2 attributes, optionally weighted by the input weight.
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Detailed Description

Generate and return the (weighted) mean of an input sample of nsam observations with ndim = 1 or 2 attributes, optionally weighted by the input weight.

Parameters

[in]	sample	: The `contiguous` array of shape `(nsam)`, `(ndim, nsam)` or `(nsam, ndim)` of, type `complex` of kind any supported by the processor (e.g., CK, CK32, CK64, or CK128), type `real` of kind any supported by the processor (e.g., RK, RK32, RK64, or RK128), containing the sample whose `mean` is to be computed.
[in]	dim	: The input scalar `integer` of default kind IK representing the dimension (`1` or `2`) of the input `sample` along which the mean must be computed. If `dim = 1`, the input `sample` of rank `2` is assumed to have the shape `(nsam, ndim)`. If `dim = 2`, the input `sample` of rank `2` is assumed to have the shape `(ndim, nsam)`. The input `dim` must always be `1` or missing for an input `sample` of rank `1`. (optional. If missing, the mean of the whole input `sample` is computed.)
[in]	weight	: The `contiguous` vector of length `nsam` of type `integer` of default kind IK, or type `real` of the same kind as that of the output `mean`, containing the corresponding weights of the data points in the input `sample`. (optional, default = a vector of ones.)

Returns

mean : The output object of the same type and kind as the input sample.

When the input sample has the shape (nsam), or (:,:) and dim is missing, the output mean is a scalar.
When the input sample has the shape (nsam, ndim) or (ndim, nsam), the output mean is a vector of length ndim.

Possible calling interfaces ⛓

: use pm_sampleMean, only: getMean

! 1D sample.

mean = getMean(sample(1 : nsam))

mean = getMean(sample(1 : nsam), weight(1 : nsam))

mean = getMean(sample(1 : nsam), dim)

mean = getMean(sample(1 : nsam), dim, weight(1 : nsam))

! 2D sample.

mean(1 : ndim) = getMean(sample(:,:))

mean(1 : ndim) = getMean(sample(:,:), weight(1 : nsam))

mean(1 : ndim) = getMean(sample(:,:), dim)

mean(1 : ndim) = getMean(sample(:,:), dim, weight(1 : nsam))

pm_sampleMean::getMean
Generate and return the (weighted) mean of an input sample of nsam observations with ndim = 1 or 2 at...
Definition: pm_sampleMean.F90:229

pm_sampleMean
This module contains classes and procedures for computing the first moment (i.e., the statistical mea...
Definition: pm_sampleMean.F90:104

Warning: The condition all(0. <= weight) must hold for the corresponding input arguments.
The condition 1 <= dim .and. dim <= rank(sample) must hold for the corresponding input arguments.
The condition size(sample, dim) == size(weight, 1) must hold for the corresponding input arguments.
These conditions are verified only if the library is built with the preprocessor macro CHECK_ENABLED=1.; The pure procedure(s) documented herein become impure when the ParaMonte library is compiled with preprocessor macro CHECK_ENABLED=1.
By default, these procedures are pure in release build and impure in debug and testing builds.

Note

If the input sample is to be an array of type integer, simply convert the sample to an array of type real of the desired kind for the output real mean of the sample.
There is no point in accepting an input sample of type integer since it will be inevitably converted to an array of type real within the procedure to avoid potential integer overflow.
Furthermore, an sample of type integer creates ambiguity about the kind of the real-valued returned mean by the procedure.
It is therefore sensible to offer interfaces for only weights of type integer of default kind and real of the same kind as the sample.

Note that the mean of any one or two-dimensional sample can be simply computed via the Fortran intrinsic routine sum():

integer                         :: i
integer , parameter             :: NDIM = 3_IK
integer , parameter             :: NSAM = 1000_IK
real    , parameter             :: sample(NDIM,NSAM) = reshape([( real(i,RK), i = 1, NSAM )], shape = shape(sample))
real    , allocatable   :: mean(:)
mean = sum(sample, dim = 1) / size(transpose(sample), dim = 1)  ! assuming the first dimension represents the observations.
mean = sum(sample, dim = 2) / size(sample, dim = 2)             ! assuming the second dimension represents the observations.

The mean of a whole multidimensional array can be obtained by either

reshaping the array to a vector form and passing it to this procedure, or
mapping the array to a 1-dimensional pointer array of the same size as the ndim dimensional array.

See the examples below.

Developer Remark:: An XY input sample interface is impossible due to ambiguity with existing interfaces.

See also: getVar
setMean
setVarMean

Example usage ⛓

: 1program example

2

3 use pm_kind, only: SK, IK

4 use pm_kind, only: TKG => RKS ! All other real types are also supported.

5 use pm_sampleMean, only: getMean

6 use pm_arrayRange, only: getRange

7 use pm_distUnif, only: getUnifRand

8 use pm_io, only: display_type

9

10 implicit none

11

12 integer(IK) :: idim, ndim, nsam

13 type(display_type) :: disp

14 disp = display_type(file = "main.out.F90")

15

16 call disp%skip()

17 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

18 call disp%show("!Compute the mean of a 1-D array.")

19 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

20 call disp%skip()

21

22 block

23 real(TKG) :: mean

24 real(TKG), allocatable :: sample(:)

25 call disp%skip()

26 call disp%show("nsam = getUnifRand(1, 5)")

27 nsam = getUnifRand(1, 5)

28 call disp%show("sample = getUnifRand(0., 1., nsam)")

29 sample = getUnifRand(0., 1., nsam)

30 call disp%show("sample")

31 call disp%show( sample )

32 call disp%show("getMean(sample)")

33 call disp%show( getMean(sample) )

34 call disp%show("mean = getMean(sample, dim = 1_IK)")

35 mean = getMean(sample, dim = 1_IK)

36 call disp%show("mean")

37 call disp%show( mean )

38 call disp%skip()

39 end block

40

41 call disp%skip()

42 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

43 call disp%show("!Compute the mean of a 2-D array along a specific dimension.")

44 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

45 call disp%skip()

46

47 block

48 real(TKG), allocatable :: mean(:)

49 real(TKG), allocatable :: sample(:,:)

50 call disp%skip()

51 call disp%show("ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)")

52 ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)

53 call disp%show("sample = getUnifRand(0., 1., ndim, nsam)")

54 sample = getUnifRand(0., 1., ndim, nsam)

55 call disp%show("sample")

56 call disp%show( sample )

57 call disp%show("getMean(sample)")

58 call disp%show( getMean(sample) )

59 call disp%show("mean = getMean(sample, dim = 2_IK)")

60 mean = getMean(sample, dim = 2_IK)

61 call disp%show("mean")

62 call disp%show( mean )

63 call disp%show("mean = getMean(transpose(sample), dim = 1_IK)")

64 mean = getMean(transpose(sample), dim = 1_IK)

65 call disp%show("mean")

66 call disp%show( mean )

67 call disp%skip()

68 end block

69

70 call disp%skip()

71 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

72 call disp%show("!Compute the mean of a 1-D weighted array.")

73 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

74 call disp%skip()

75

76 block

77 real(TKG) :: mean

78 real(TKG), allocatable :: sample(:)

79 integer(IK), allocatable :: weight(:)

80 call disp%skip()

81 call disp%show("nsam = getUnifRand(1, 5)")

82 nsam = getUnifRand(1, 5)

83 call disp%show("sample = getUnifRand(0., 1., nsam)")

84 sample = getUnifRand(0., 1., nsam)

85 call disp%show("sample")

86 call disp%show( sample )

87 call disp%show("weight = getUnifRand(1, 9, nsam)")

88 weight = getUnifRand(1, 9, nsam)

89 call disp%show("weight")

90 call disp%show( weight )

91 call disp%show("mean = getMean(sample)")

92 mean = getMean(sample)

93 call disp%show("mean")

94 call disp%show( mean )

95 call disp%show("mean = getMean(sample, weight)")

96 mean = getMean(sample, weight)

97 call disp%show("mean")

98 call disp%show( mean )

99 call disp%show("mean = getMean(sample, 1_IK, weight)")

100 mean = getMean(sample, 1_IK, weight)

101 call disp%show("mean")

102 call disp%show( mean )

103 call disp%skip()

104 end block

105

106 call disp%skip()

107 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

108 call disp%show("!Compute the mean of a 1-D weighted array.")

109 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

110 call disp%skip()

111

112 block

113 real(TKG) :: mean

114 real(TKG), allocatable :: sample(:)

115 real(TKG), allocatable :: weight(:)

116 call disp%skip()

117 call disp%show("nsam = getUnifRand(1, 5)")

118 nsam = getUnifRand(1, 5)

119 call disp%show("sample = getUnifRand(0., 1., nsam)")

120 sample = getUnifRand(0., 1., nsam)

121 call disp%show("sample")

122 call disp%show( sample )

123 call disp%show("weight = getUnifRand(0., 1., nsam)")

124 weight = getUnifRand(0., 1., nsam)

125 call disp%show("weight")

126 call disp%show( weight )

127 call disp%show("mean = getMean(sample)")

128 mean = getMean(sample)

129 call disp%show("mean")

130 call disp%show( mean )

131 call disp%show("mean = getMean(sample, weight)")

132 mean = getMean(sample, weight)

133 call disp%show("mean")

134 call disp%show( mean )

135 call disp%show("mean = getMean(sample, 1_IK, weight)")

136 mean = getMean(sample, 1_IK, weight)

137 call disp%show("mean")

138 call disp%show( mean )

139 call disp%skip()

140 end block

141

142 call disp%skip()

143 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

144 call disp%show("!Compute the mean of a 2-D weighted array along a specific dimension.")

145 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

146 call disp%skip()

147

148 block

149 real(TKG), allocatable :: mean(:)

150 real(TKG), allocatable :: sample(:,:)

151 real(TKG), allocatable :: weight(:)

152 call disp%skip()

153 call disp%show("ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)")

154 ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)

155 call disp%show("sample = getUnifRand(0., 1., ndim, nsam)")

156 sample = getUnifRand(0., 1., ndim, nsam)

157 call disp%show("sample")

158 call disp%show( sample )

159 call disp%show("weight = getUnifRand(0., 1., nsam)")

160 weight = getUnifRand(0., 1., nsam)

161 call disp%show("weight")

162 call disp%show( weight )

163 call disp%show("getMean(sample, [(weight, idim = 1, ndim)])")

164 call disp%show( getMean(sample, [(weight, idim = 1, ndim)]) )

165 call disp%show("mean = getMean(sample, 2_IK, weight)")

166 mean = getMean(sample, 2_IK, weight)

167 call disp%show("mean")

168 call disp%show( mean )

169 call disp%show("mean = getMean(transpose(sample), 1_IK, weight)")

170 mean = getMean(transpose(sample), 1_IK, weight)

171 call disp%show("mean")

172 call disp%show( mean )

173 call disp%skip()

174 end block

175

176 call disp%skip()

177 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

178 call disp%show("!Compute the mean of a multidimensional array by associating it with a 1D pointer.")

179 call disp%show("!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

180 call disp%skip()

181

182 block

183 integer(IK) :: nslice

184 real(TKG), allocatable :: mean

185 real(TKG), allocatable, target :: sample(:,:,:)

186 real(TKG), pointer :: samptr(:)

187 call disp%skip()

188 call disp%show("ndim = getUnifRand(1, 2); nsam = getUnifRand(1, 3); nslice = getUnifRand(1, 4)")

189 ndim = getUnifRand(1, 2); nsam = getUnifRand(1, 3); nslice = getUnifRand(1, 4)

190 call disp%show("sample = getUnifRand(0., 1., ndim, nsam, nslice)")

191 sample = getUnifRand(0., 1., ndim, nsam, nslice)

192 call disp%show("sample")

193 call disp%show( sample )

194 call disp%show("shape(sample)")

195 call disp%show( shape(sample) )

196 call disp%show("samptr(1:product(shape(sample))) => sample")

197 samptr(1:product(shape(sample))) => sample

198 call disp%show("mean = getMean(samptr)")

199 mean = getMean(samptr)

200 call disp%show("nullify(samptr)")

201 nullify(samptr)

202 call disp%show("mean")

203 call disp%show( mean )

204 call disp%show("mean = getMean(reshape(sample, [product(shape(sample))]))")

205 mean = getMean(reshape(sample, [product(shape(sample))]))

206 call disp%show("mean")

207 call disp%show( mean )

208 call disp%skip()

209 end block

210

211end program example

pm_arrayRange::getRange
Generate minimally-spaced character, integer, real sequences or sequences at fixed intervals of size ...
Definition: pm_arrayRange.F90:135

pm_distUnif::getUnifRand
Generate and return a scalar or a contiguous array of rank 1 of length s1 of randomly uniformly distr...
Definition: pm_distUnif.F90:4150

pm_io::show
This is a generic method of the derived type display_type with pass attribute.
Definition: pm_io.F90:11726

pm_io::skip
This is a generic method of the derived type display_type with pass attribute.
Definition: pm_io.F90:11508

pm_arrayRange
This module contains procedures and generic interfaces for generating ranges of discrete character,...
Definition: pm_arrayRange.F90:36

pm_distUnif
This module contains classes and procedures for computing various statistical quantities related to t...
Definition: pm_distUnif.F90:274

pm_io
This module contains classes and procedures for input/output (IO) or generic display operations on st...
Definition: pm_io.F90:252

pm_io::disp
type(display_type) disp
This is a scalar module variable an object of type display_type for general display.
Definition: pm_io.F90:11393

pm_kind
This module defines the relevant Fortran kind type-parameters frequently used in the ParaMonte librar...
Definition: pm_kind.F90:268

pm_kind::IK
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

pm_kind::SK
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

pm_kind::RKS
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

pm_io::display_type
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!Compute the mean of a 1-D array.

4!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

5

6

7nsam = getUnifRand(1, 5)

8sample = getUnifRand(0., 1., nsam)

9sample

10+0.859427989, +0.353745699, +0.293616951, +0.262036860

11getMean(sample)

12+0.442206860

13mean = getMean(sample, dim = 1_IK)

14mean

15+0.442206860

16

17

18!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

19!Compute the mean of a 2-D array along a specific dimension.

20!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

21

22

23ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)

24sample = getUnifRand(0., 1., ndim, nsam)

25sample

26+0.336883903, +0.978171170, +0.686017036

27+0.551356018, +0.250263155, +0.141360044

28getMean(sample)

29+0.490675211

30mean = getMean(sample, dim = 2_IK)

31mean

32+0.667024076, +0.314326406

33mean = getMean(transpose(sample), dim = 1_IK)

34mean

35+0.667024076, +0.314326406

36

37

38!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

39!Compute the mean of a 1-D weighted array.

40!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

41

42

43nsam = getUnifRand(1, 5)

44sample = getUnifRand(0., 1., nsam)

45sample

46+0.307034671, +0.588855505, +0.269147933, +0.759839654, +0.727329195

47weight = getUnifRand(1, 9, nsam)

48weight

49+9, +2, +1, +1, +3

50mean = getMean(sample)

51mean

52+0.530441403

53mean = getMean(sample, weight)

54mean

55+0.446999907

56mean = getMean(sample, 1_IK, weight)

57mean

58+0.446999907

59

60

61!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

62!Compute the mean of a 1-D weighted array.

63!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

64

65

66nsam = getUnifRand(1, 5)

67sample = getUnifRand(0., 1., nsam)

68sample

69+0.596352220

70weight = getUnifRand(0., 1., nsam)

71weight

72+0.957002521

73mean = getMean(sample)

74mean

75+0.596352220

76mean = getMean(sample, weight)

77mean

78+0.596352220

79mean = getMean(sample, 1_IK, weight)

80mean

81+0.596352220

82

83

84!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

85!Compute the mean of a 2-D weighted array along a specific dimension.

86!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

87

88

89ndim = getUnifRand(1, 3); nsam = getUnifRand(1, 5)

90sample = getUnifRand(0., 1., ndim, nsam)

91sample

92+0.613177538, +0.954005778, +0.143002987, +0.308543265, +0.799150944

93weight = getUnifRand(0., 1., nsam)

94weight

95+0.558582485, +0.612668514, +0.499010265, +0.254969299, +0.483779669

96getMean(sample, [(weight, idim = 1, ndim)])

97+0.607569635

98mean = getMean(sample, 2_IK, weight)

99mean

100+0.607569575

101mean = getMean(transpose(sample), 1_IK, weight)

102mean

103+0.607569575

104

105

106!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

107!Compute the mean of a multidimensional array by associating it with a 1D pointer.

108!%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

109

110

111ndim = getUnifRand(1, 2); nsam = getUnifRand(1, 3); nslice = getUnifRand(1, 4)

112sample = getUnifRand(0., 1., ndim, nsam, nslice)

113sample

114slice(:,:,1) =

115+0.756028056

116shape(sample)

117+1, +1, +1

118samptr(1:product(shape(sample))) => sample

119mean = getMean(samptr)

120nullify(samptr)

121mean

122+0.756028056

123mean = getMean(reshape(sample, [product(shape(sample))]))

124mean

125+0.756028056

126

127

Test:: test_pm_sampleMean

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.
For details on the naming abbreviations, see this page.
For details on the naming conventions, see this page.
This software is distributed under the MIT license with additional terms outlined below.

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.
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.

This software is available to the public under a highly permissive license.
Help us justify its continued development and maintenance by acknowledging its benefit to society, distributing it, and contributing to it.

Copyright: Computational Data Science Lab

Author:: Amir Shahmoradi, April 21, 2017, 1:54 AM, Institute for Computational Engineering and Sciences (ICES), The University of Texas Austin

Definition at line 229 of file pm_sampleMean.F90.

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

src/fortran/main/pm_sampleMean.F90