In daily use, vectors and matrices are more practical than higher-order arrays,
and Fortran does not support array generics, we can use reshape to reshape vectors into higher-order arrays.
real :: x(2,3,4)
x = reshape(randn(mean=0.0, std=1.0, ndim=2*3*4), [2,3,4])
randuGenerate an uniformly distributed data scalar or vector.
Experimental.
Impure function.
random = randu(start, end [, ndim])
random/start/end should keep the same type and kind.
start: Shall be an integer/real scalar.
This argument is intenet(in).
end: Shall be an integer/real scalar.
This argument is inetent(in).
ndim: Shall be an integer scalar.
This argument is intent(in) and optional.
Returns an integer/real scalar or rank-1 array.
program demo_stats_randu
use forlab_stats, only: randu
print *, "running `demo_stats_randu`.."
print *, randu(start=1, end=2)
print *, randu(start=1.0, end=2.0, ndim=3)
print *, reshape(randu(1.0, 2.0, 2*2), [2,2])
!> Possible output:
!! 2
!! 1.65676987 1.11625218 1.03502560
!! 1.74973476 1.82997108 1.77998054 1.14384007
end program demo_stats_randu
randnGenerate a normal distributed data scalar or vector.
Experimental.
Impure function.
random = randn(mean, std [, ndim])
random/mean/std should keep the same type and kind.
mean: Shall be an integer/real scalar.
This argument is intenet(in).
std: Shall be an integer/real scalar.
This argument is inetent(in).
ndim: Shall be an integer scalar.
This argument is intent(in) and optional.
Returns an integer/real scalar or rank-1 array.
program demo_stats_randn
use forlab_stats, only: randn
print *, "running `demo_stats_randn`.."
print *, randn(mean=0.0, std=2.0)
print *, randn(mean=0.0, std=2.0, ndim=3)
print *, reshape(randn(0.0, 2.0, 2*2), [2,2])
!> Chi-square distribution of 3 degrees of freedom
print *, sum(randn(mean=0.0, std=1.0, ndim=3)**2)
print *, sum(reshape(randn(mean=0.0, std=1.0, ndim=5*3), [5, 3])**2, dim=2)
!> Possible output:
!! -0.387298465
!! -1.37615824 -0.529266298 5.43095016
!! -1.35311902 1.81701779 0.772518456 -0.269844353
!! 9.45483303
!! 0.962645471 0.698421597 0.687875450 4.75956964 1.71025097
end program demo_stats_randn