011. sum and other array functions have an optional dimension argument

topic: Arrays

sum-dim.f90 | | |

integer :: v(2,3)  ! 2x3 matrix

v(1,:) = [1, 2, 3]
v(2,:) = 10*v(1,:)  ! [10, 20, 30]

print *, v  ! elements in column-major order

print *, sum(v)         ! sum all elements: 66
print *, sum(v, dim=1)  ! sum each col (along row dim): 11 22 33
print *, sum(v, dim=2)  ! sum each row (along col dim): 6 60

end

Output1

           1          10           2          20           3          30
          66
          11          22          33
           6          60

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sum and other array functions have an optional dim(ension) argument

integer :: v(2,3) ! 2x3 matrix
v(1,:) = [1,2,3]
v(2,:) = 10*v(1,:) ! set to [10,20,30]
print*,sum(v) ! all elements: 66
print*,sum(v,dim=1) ! sum each row: 6 60
print*,sum(v,dim=2) ! sum each col: 11 22 33

— FortranTip (@fortrantip) December 18, 2021

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Compiled using GNU Fortran (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0 with no flags