What does colon mean in fortran?

Question

I'm trying to convert fortran code to matlab, I was wondering if someone could help me with this subroutine. I'm specifically asking what does the colon mean in these lines?

SUB Taper (a(), co(), Re(), Im())

FOR nd = 0 TO 31

         n1 = 8 * nd: n2 = a(n1 + 4): n1 = a(n1): n0 = 255 - nd
         a = .5 * (1 - co(n1)): b = .5 * (1 - co(n2))
         Re(nd) = a * Re(nd): Im(nd) = b * Im(nd)
         Re(n0) = b * Re(n0): Im(n0) = a * Im(n0)

NEXT

END SUB

That looks more like VB than Fortran. – francescalus Feb 26 '14 at 22:05 — francescalus, Feb 26 '14 at 22:05

score 2 · Answer 1 · edited May 23 '17 at 10:26

2

The code fragment in your question has not a valid Fortran syntax. It is VB and colon is used as statement separator

edited May 23 '17 at 10:26

Community

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answered Feb 27 '14 at 09:54

Peter Petrik

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score -1 · Answer 2 · answered Feb 26 '14 at 21:59

-1

Fortran90 and up allow you to access a single array value given an index, and access a subarray given a range of indices separated by a colon.

Fortran = Beginning : End : Increment
MatLab  = Beginning : Increment : End

There is a table at the bottom of page 5 in this doc that shows the Fortran and MatLab equivalents.

answered Feb 26 '14 at 21:59

Drewness

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That is true, and there is also the colon edit descriptor in Fortran. However, neither of these applies as the code fragment is not Fortran. – francescalus Feb 26 '14 at 22:36
@francescalus - Agreed. – Drewness Feb 26 '14 at 22:37
So yea it is actually basic, I thought the whole time it was fortran! That clears up a lot : P – Chris Feb 26 '14 at 22:53

What does colon mean in fortran?

2 Answers2