namelist input of multidimensional array?
in [Fortran]
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From: jshine on 20 Jan 2010 13:06 I'm curious if anyone has some example code of how to input a 2-D (or, in principle, n-D) array via a namelist file in Fortran 95 (I'm using a reasonably current "gfortran" compiler)? I can load a 1-D array (a vector) easily enough and have tried a number of permutations on that syntax, but I haven't been successful yet. ...nor have I found any good examples of this via Google or in any of my Fortran books. Any help will be appreciated! Thanks, -Jon
From: Richard Maine on 20 Jan 2010 13:33 jshine <jtomshine(a)gmail.com> wrote: > I'm curious if anyone has some example code of how to input a 2-D (or, > in principle, n-D) array via a namelist file in Fortran 95 (I'm using > a reasonably current "gfortran" compiler)? I can load a 1-D array (a > vector) easily enough and have tried a number of permutations on that > syntax, but I haven't been successful yet. ...nor have I found any > good examples of this via Google or in any of my Fortran books. You input the elements in array sequence order, as in x = 1,2,3,4 which, for an x dimensioned 2x2, gets you the array 1 3 2 4 You do have to understand array sequence order. There is no explicit separation of rows/columns. Nor is there any kind of slice notation. -- Richard Maine | Good judgment comes from experience; email: last name at domain . net | experience comes from bad judgment. domain: summertriangle | -- Mark Twain
From: glen herrmannsfeldt on 20 Jan 2010 15:09 Richard Maine <nospam(a)see.signature> wrote: > jshine <jtomshine(a)gmail.com> wrote: >> I'm curious if anyone has some example code of how to input a 2-D (or, >> in principle, n-D) array via a namelist file in Fortran 95 (I'm using >> a reasonably current "gfortran" compiler)? I can load a 1-D array (a >> vector) easily enough and have tried a number of permutations on that >> syntax, but I haven't been successful yet. ...nor have I found any >> good examples of this via Google or in any of my Fortran books. > You input the elements in array sequence order, as in > x = 1,2,3,4 > which, for an x dimensioned 2x2, gets you the array > 1 3 > 2 4 > You do have to understand array sequence order. There is no explicit > separation of rows/columns. Nor is there any kind of slice notation. It seems that for F2003 (10.10.1.1) that subscripts, strides, and substring expressions are allowed. The example given uses: &TODAY I = 12345, X(1) = 12345, X(3:4) = 2*1.5, I=6, ! This is a comment. P = ..ISN.T_BOB.S.., Z = (123,0)/ (It might wrap when I post it, but the comment should be on the end of the first line.) If an array name or structure is used then a list of elements not longer than needed to fill the given array/structure is allowed (as Richard indicated). Multipliers can be used in place of repeated constants. The example is a shorter form of: X(3:4)= 1.5, 1.5, or of X(3)=1.5, X(4)=1.5, One that seems not to be allowed is vector subscripts. Also, null elements (commas without any value in between) are allowed, as are null elements with a multiplier. (Useful for filling parts of a large array.) -- glen
From: Ron Shepard on 20 Jan 2010 15:10 In article <1jcm55s.1gyb0g61fu8gvcN%nospam(a)see.signature>, nospam(a)see.signature (Richard Maine) wrote: > jshine <jtomshine(a)gmail.com> wrote: > > > I'm curious if anyone has some example code of how to input a 2-D (or, > > in principle, n-D) array via a namelist file in Fortran 95 (I'm using > > a reasonably current "gfortran" compiler)? I can load a 1-D array (a > > vector) easily enough and have tried a number of permutations on that > > syntax, but I haven't been successful yet. ...nor have I found any > > good examples of this via Google or in any of my Fortran books. > > You input the elements in array sequence order, as in > > x = 1,2,3,4 > > which, for an x dimensioned 2x2, gets you the array > > 1 3 > 2 4 > > You do have to understand array sequence order. There is no explicit > separation of rows/columns. Nor is there any kind of slice notation. The above is correct (of course), but here is another answer. You can use namelist write statements to write out the data, and in almost all situations that output is in the correct format to be read by some subsequent namelist read statement. I think this works also for user defined data types. I don't remember the exact situations now, but the exceptions to this write/read symmetry involve character items with embedded spaces or quote characters (',"). $.02 -Ron Shepard
From: Richard Maine on 20 Jan 2010 16:57
glen herrmannsfeldt <gah(a)ugcs.caltech.edu> wrote: > Richard Maine <nospam(a)see.signature> wrote: > > Nor is there any kind of slice notation. > > It seems that for F2003 (10.10.1.1) that subscripts, strides, > and substring expressions are allowed. Oh, I had forgotten about that. (I pretty much stopped using namelist myself at about the time it was standardized). Thanks for the correction. I was probably thinking about how you can't do things like x(k)=12345 because the k isn't available. -- Richard Maine | Good judgment comes from experience; email: last name at domain . net | experience comes from bad judgment. domain: summertriangle | -- Mark Twain |