Two named structures with the same name that won't concatenate. Anysuggestions?

So, I'm really confused. The current code I am building repeatedly
uses the line:

cld = [[cld], [startCld(flist[i], pInd, lat[pInd],
lon[pInd], date[pInd], time[pInd])]]

where "cld" is an array of named structures and "startCld" is a
function that creates a named structure. In both cases, the array is
named "cirrusStruct." The concatenation above works 70 times in a
row, however, on the 71st time it fails and gives the following error:

% Unable to concatenate variables because the dimensions do not agree:
<STRUCT Array[1]>.
% Execution halted at: FINDTHINCIRRUS 467 /home/jsolbrig/geoprof-
lidar/findThinCirrus.pro
% $MAIN$

Now, after the error has occurred, if I use the "startCld" routine
from command line to create a structure "a," then type "help, cld, a, /
structure" they appear to be exactly alike, however still will not
concatenate.

IDL> help, cld, a
CLD STRUCT = -> CIRRUSSTRUCT Array[70]
A STRUCT = -> CIRRUSSTRUCT Array[1]

IDL> help, cld, a, /str
;Help info for "help, cld, /str"
** Structure CIRRUSSTRUCT, 12 tags, length=112, data length=108:
STARTDATE LONG 20060701
STARTTIME DOUBLE 0.016666668
STARTFILE STRING '/sn1/jsolbrig/GEOPROF-Lidar/
jul06/2006182000103_00927_CS_2B-GEOPROF-
LIDAR_GRANULE_P1_R04_E00.hdf.zip'
ENDFILE STRING '/sn1/jsolbrig/GEOPROF-Lidar/
jul06/2006182000103_00927_CS_2B-GEOPROF-
LIDAR_GRANULE_P1_R04_E00.hdf.zip'
STARTPROF DOUBLE 151.00000
ENDPROF DOUBLE 151.00000
STARTLAT DOUBLE -1.4628147
ENDLAT DOUBLE -1.4628147
STARTLON DOUBLE 25.093336
ENDLON DOUBLE 25.093336
MAXTHK DOUBLE 0.0000000
MINTHK DOUBLE 0.0000000

;Help info for "help, a, /str"
** Structure CIRRUSSTRUCT, 12 tags, length=112, data length=108:
STARTDATE LONG 20060701
STARTTIME DOUBLE 9.8166666
STARTFILE STRING '/sn1/jsolbrig/GEOPROF-Lidar/
jul06/2006182081529_00932_CS_2B-GEOPROF-
LIDAR_GRANULE_P1_R04_E00.hdf.zip'
ENDFILE STRING ''
STARTPROF DOUBLE 35189.000
ENDPROF DOUBLE 0.0000000
STARTLAT DOUBLE 18.281832
ENDLAT DOUBLE 0.0000000
STARTLON DOUBLE -118.93538
ENDLON DOUBLE 0.0000000
MAXTHK DOUBLE 0.0000000
MINTHK DOUBLE 0.0000000

;Concatenating arrays of structures
DL> cld = [[cld], [a]]
% Unable to concatenate variables because the dimensions do not agree:
A.
% Execution halted at: FINDTHINCIRRUS 467 /home/jsolbrig/geoprof-
lidar/findThinCirrus.pro
% $MAIN$


After what I've said above, there are still a couple more points that
should be made.
1) The routine I am working on has previously concatenated up to
4,000 structures into the same array.
2) One of the 70 previous structures is coming directly from the
same portion of the code that is failing.

endif else if true1[pInd] eq 0 and true2[pInd] eq 1 then begin
;continuing previous cloud
prevBase = layBase[cirrusLays[1], pInd]
prevTop = layTop[cirrusLays[1], pInd]

;starting second cloud
cldMax = n_elements(cld)
cld = [[cld], [startCld(flist[i], pInd, lat[pInd],
lon[pInd], date[pInd], time[pInd])]] ;FAILS HERE
prevBase = [prevBase, layBase[cirrusLays[0], pInd]]
prevTop = [prevTop, layTop[cirrusLays[0], pInd]]
twoCldStep[pInd] = 3


If anyone has a suggestion as to how to fix this problem, I would
greatly appreciate your input.

I have solved my problem, but am still unsure why my method worked
many, many times, then decided to quit working. I would really like
to know so I don't so either I don't do something dumb again, or I can
avoid a subtle little problem I haven't thought of yet.

Thanks

On Aug 29, 1:26 am, "J. Solbrig" <JSolb...@gmail.com> wrote:
> I have solved my problem, but am still unsure why my method worked
> many, many times, then decided to quit working. I would really like
> to know so I don't so either I don't do something dumb again, or I can
> avoid a subtle little problem I haven't thought of yet.
>
> Thanks

Hi,

I think the issue may be a little clouded by the fact that your
example is with named structures. It really isn't an issue about
structures but about arrays of any type. Here's a simplifed example
of what you tried above...

SeaDAS> x = {XSTRUCT, A: 0, B: 'boo'}
SeaDAS> a = REPLICATE(x, 70)
SeaDAS> b = [[a],[x]]
% Unable to concatenate variables because the dimensions do not agree:
X.
% Execution halted at: $MAIN$
SeaDAS> help, [a,x]
<Expression> STRUCT = -> XSTRUCT Array[71]
SeaDAS> help, [[a],[a]]
<Expression> STRUCT = -> XSTRUCT Array[70, 2]


The form of concatenation that looks like [[a],[b]] tries to create
an new array with a second dimension. The form of concatenation that
looks like [a,b] simply appends b to a (which what I think you want).

Cheers,
Ben