Discrete subscripts

[h_amini]

Hello there

Can the subscripts of an array be discontinuous?

For example, how can I define a rank-one array (I) containing the elements I(5), I(6), I(21) and I(22).

Regards

Hamid

[Steven_L_Intel1]

You can't define an array like that, but you can reference those elements with a vector subscript, for example:

I([5,6,21,22])

[h_amini]

Quoting - Steve Lionel (Intel)

You can't define an array like that, but you can reference those elements with a vector subscript, for example:

I([5,6,21,22])

Thank you for this. Do you mean using something like the following program?

INTEGER I(4)

I = (/5,6,21,22/)

I(5)=50; I(6)=60; I(21)=210; I(22)=220

PRINT*, I(5), I(6), I(21), I(22)

END

[h_amini]

Quoting - h.amini

Quoting - Steve Lionel (Intel)

You can't define an array like that, but you can reference those elements with a vector subscript, for example:

I([5,6,21,22])

Thank you for this. Do you mean using something like the following program?

INTEGER I(4)

I = (/5,6,21,22/)

I(5)=50; I(6)=60; I(21)=210; I(22)=220

PRINT*, I(5), I(6), I(21), I(22)

END

Something should be wrong. He program works with more subscripts, e.g. I(7), I(8), I(23) and I(24).

INTEGER I(4)

I = (/5,6,21,22/)

I(5)=50; I(6)=60; I(21)=210; I(22)=220

I(7)=70; I(8)=80; I(23)=230; I(24)=240

PRINT*, I(5), I(6), I(21), I(22)

PRINT*, I(7), I(8), I(23), I(24)

END

[Steven_L_Intel1]

No, that's not what I meant. The program you have here is invalid as array I is dimensioned (4) and you are referencing far outside its bounds.

What I meant was something more like this:

[plain]INTEGER I(25)

I(5)=50; I(6)=60; I(21)=210; I(22)=220

I(7)=70; I(8)=80; I(23)=230; I(24)=240

PRINT*, I([5,6,21,22])

PRINT*, I([7,8,23,24])

END[/plain]

[h_amini]

Quoting - Steve Lionel (Intel)

No, that's not what I meant. The program you have here is invalid as array I is dimensioned (4) and you are referencing far outside its bounds.

What I meant was something more like this:

[plain]INTEGER I(25)

I(5)=50; I(6)=60; I(21)=210; I(22)=220

I(7)=70; I(8)=80; I(23)=230; I(24)=240

PRINT*, I([5,6,21,22])

PRINT*, I([7,8,23,24])

END[/plain]

Many thanks. But you defined a 25-element array. I wanted to have elements as less as possible, which would be an 8-element array for the above example (or 4-element for the first example).

[Steven_L_Intel1]

As I indicated earlier, you can't do that in Fortran. I suppose what you could do is define a second array with indexes into the first, but this would not save you any storage.

[h_amini]

Quoting - Steve Lionel (Intel)

As I indicated earlier, you can't do that in Fortran. I suppose what you could do is define a second array with indexes into the first, but this would not save you any storage.

So the best solution seems to be defining an array with elements from the minimum to the maximum values. As I need dynamic variables, the program in post 4 will be:

INTEGER, ALLOCATABLE :: I(:)

M = 5; N = 24

ALLOCATE (I(M:N))

I(5)=50; I(6)=60 ; I(21)=210; I(22)=220

I(7)=70; I(8)=80 ; I(23)=230; I(24)=240

PRINT*, I(5), I(6), I(21), I(22)

PRINT*, I(7), I(8), I(23), I(24)

END

Thanks very much

Hamid