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! Vector norm: demonstrate usage of the function interface
program example_get_norm
use stdlib_linalg, only: get_norm, linalg_state_type
implicit none
real :: a(3,3), nrm, nrmd(3)
integer :: j
type(linalg_state_type) :: err
! a = [ -3.00000000 0.00000000 3.00000000
! -2.00000000 1.00000000 4.00000000
! -1.00000000 2.00000000 5.00000000 ]
a = reshape([(j-4,j=1,9)], [3,3])
print "(' a = [ ',3(g0,3x),2(/9x,3(g0,3x)),']')", transpose(a)
! Norm with integer input
call get_norm(a, nrm, 2)
print *, 'Euclidean norm = ',nrm ! 8.30662346
! Norm with character input
call get_norm(a, nrm, '2')
print *, 'Euclidean norm = ',nrm ! 8.30662346
! Euclidean norm of row arrays, a(i,:)
call get_norm(a, nrmd, 2, dim=2)
print *, 'Rows norms = ',nrmd ! 4.24264050 4.58257580 5.47722578
! Euclidean norm of columns arrays, a(:,i)
call get_norm(a, nrmd, 2, dim=1)
print *, 'Columns norms = ',nrmd ! 3.74165750 2.23606801 7.07106781
! Infinity norms
call get_norm(a, nrm, 'inf')
print *, 'maxval(||a||) = ',nrm ! 5.00000000
call get_norm(a, nrmd, 'inf', dim=2)
print *, 'maxval(||a(i,:)||) = ',nrmd ! 3.00000000 4.00000000 5.00000000
call get_norm(a, nrm, '-inf')
print *, 'minval(||a||) = ',nrm ! 0.00000000
call get_norm(a, nrmd, '-inf', dim=1)
print *, 'minval(||a(:,i)||) = ',nrmd ! 1.00000000 0.00000000 3.00000000
! Catch Error:
! [norm] returned Value Error: dimension 4 is out of rank for shape(a)= [3, 3]
call get_norm(a, nrmd, 'inf', dim=4, err=err)
print *, 'invalid: ',err%print()
end program example_get_norm
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