I tried several coding approaches, maybe you can show me the way. I'll explain why I gave up on avStartWatch.

I have an xml file, template.xml, that contains a considerable amount of html and javascript to create the various graphs that I want to use. I pinched this code from astrojet.h5 (after converting it to xml). I modified the astrojet file slightly and replaced numbers relating to the array dimensions with strings that I can later detect and replace.

This is the procedure that works. In my Fortran program I read template.xml and write test.xml with my dataset (dset) and appropriately modified html and javascript to create the graphs. Now I can open test.xml with avOpen and view the data with the 3D graphs, and use avGetObject and avWriteElement to change the array one entry at a time and view the changes while live.

When I try using avStartWatch after the avOpen, asking to watch dset, it creates a second dataset called dset(2). If I use avStartWatch without having opened test.xml then dset is the only dataset, but I do not have the graphs that I need. How can I get access to the graph code in test.xml without loading the dset dataset? If I open test.xml with AV, delete dset and save the file as test_null.xml, this new file with just the graph code, no dataset, cannot be opened by AV (not surprisingly).

Am I missing something obvious?

That's right, Jim, it's all about using the existing excellent graphing code (presumably the work of John Readey). My approach works, but making a subroutine call to update each array entry chews up a lot of CPU, and if I were to update the display on a continuous basis it would slow my program down too much. It would be very nice to be able to write directly to the dataset memory, which (in principle) is really just a matter of getting the address of that block. Your suggestion sounds promising. I didn't think of modifying the graph (etc) properties as a way of getting them to use a different dataset.
I'll report back when I've tried this...

... Looking at the graph/plot code in the xml file, I see that references to the dataset name ("dset") occur in the javascript. This code handles the sliders that move slices around, the very nice feature that I'm particularly interested in having. It looks as if the javascript would need to be modified "on the fly" in order to make the plots use a different dataset. This seems to be a bridge too far...

Gib

You make it sound so easy, Jim. I'm not saying you are wrong, but have you looked at the code in astrojet.h5? I'm not sure that it is as straightforward as you indicate.

I have tried some variations on what you suggest, handicapped of course by my primitive level of understanding of how it all works. The first observation is that the name of the dataset (currently "dset") crops up in several places. The dataset definition contains definitions for a number of sections, "slice1", "slice2", "slice3", "sec1", "sec2", "sec3" that are used to construct the graphs.

If I manually edit the file and change the dataset name to "dsetold", leaving all the other references to "dset" as they are, then avOpen() the file and avStartWatch() a new dataset called "dset", then view the result, I see two datasets as expected, "dsetold" and "dset". "dsetold" still has the various sections associated with it, "dset" has no sections associated. The graphs are all blank - it seems that they have not been linked to the new dataset "dset". If I click on a page with a slider a runtime error is generated. (I think this could be related to the fact that although "dsetold" is a 0-based array, the array "dset" that was created by avStartWatch() is 1-based. Without expecting it to have any effect, I changed my Fortran to make dset 0-based - it did nothing.) EDIT: Correction - this error is not related to the array basing, since it occurs when viewing the file before the avStartWatch() call. Clearly it is an effect of changing the name of the dataset, but it isn't fixed by adding back a dataset called "dset".

I'd be very grateful if you could give more explicit instructions as to how I can do this.

Thanks
Gib

I've realized that the path I'm on is taking me to the avLoadTemplate() routine, which in principle does exactly what I want. I have therefore made a template file with the dataset dset removed. I can load this then create a dataset called dset with avStartWatch(). So far so good. I found that by manually creating the required dset sections in AV (i.e. slice1, slice2, etc.) I can get some of the graph functionality. so set about creating these using library calls. My first attempt to use avCreateNewSection() is not successful. Here is the code (minus a couple of declarations):

character(*), parameter :: dsetpath = '/dset'
integer(int_ptr_kind()) :: object, item
integer :: N, viewerId, status, indx(3), lbnd(3), dim3d(3)
logical :: load_template = .true.

N = 50
allocate(dset(0:N-1,0:N-1,0:N-1))
dim3d = shape(dset)
lbnd = 0

if (load_template) then
call avLoadTemplate('template_nodset.xml','',status)
call avStartWatch(loc(dset),3,dim3d, AV_REAL4,"dset",status)
call avLBound(loc(dset),lbnd,status)
call make_test_array(N,dset)
call avNewViewer(viewerId)
call avVisible(viewerId, AV_TRUE, status)
object = avGetObject(dsetpath)
write(*,*) 'dset object: ',object
call avCreateNewSection(object, "slice1", item)
write(*,*) 'slice1 item: ',item
write(*,*) 'Hit enter to end ...'
read(*,*)
stop
endif

This doesn't indicate any errors, the value returned for object looks reasonable (17707532) but the value returned for item is 0, which doesn't look right, and AV does not show that a section has been created for "dset". Can someone tell me how to use avCreateNewSection() to create a section?

Gib

Thanks Jim, this debug stepping and viewing might be useful.

I have found that I can make things almost work by adding the required sections manually in AV after my program fires it up, so it is natural to try adding sections using library calls. It seems to me a rather fundamental problem that I can't get this to work. The documentation is a bit ambiguous, in that it doesn't say what 'object' points to:

Fortran syntax
subroutine avCreateNewSection(object, name, item)
integer(int_ptr_kind()), intent(IN) :: object
character(*), intent(IN) :: name
integer(int_Ptr_kind()), intent(OUT) :: item
end subroutine avCreateNewSection

I assumed that it would point to the dataset, i.e. object = avGetObject('/dset'), but that does not work - avCreateNewSection(object,"slice1",item) returns item = 0.

Can someone tell me how to add a section using the Fortran library routines?

I haven't done what you are doing but I do muck around with graphs.

For avCreatGraph3DObj I supply as 1st argument avGraphs(hRoot), where hRoot is the result from avGetObject("/").

I am guessing that you will need something like avDatasets(hRoot) to get a handle to the data sets

If I were to venture a guess

avCreateNewSection(avGraphs(avGetObject("/")), "dset/slice1", item)
or
avCreateNewSection((avGetObject("data:/dset")), "slice1", item)

Where "data:" might be different (?dataset:?)

It is a sad fact that the documentation lags behind this marvolus work. My guess the documentation was one of these auto-generated pieces of work. The doc is full of properties and methods but is void of context. The lack of context is a difficult barrier to overcome when trying to learn how to program with the API.

Jim Dempsey

Hi Jim, I appreciate your efforts. Yes, I have created dset (with avStartWatch) when trying to add a section. I can see dset in AV, and can add sections manually there.

hRoot = avGetObject("/") returns 16788532 (good)
hData = avGetObject("/dset") returns 16790060 (good)
avGetObject("data:.dset") and avGetObject("dataset:/dset") both return 0 (bad)

It looks as if hData must be the right object handle for dset. But
call avCreateNewSection(hData,"slice1",item)
gives item = 0, as does
call avCreateNewSection(hRoot,"dset/slice1",item)
and in both cases AV shows that nothing was created.

I'm starting to wonder if it really is possible to do this with Fortran. Maybe this is one of the things that was not completed. It is a great shame about the documentation, but not surprising - who likes to write the docs? I was hoping that John Readey might show up. Perhaps it wasn't diplomatic, or even considerate, to address my post to him personally. :-(

Gib

This is fun (if you are a bit twisted and have lots of time - time is the constraint for me). Thanks for reminding me that there is source code. Looking in AvObjMod.f90 I see that the first argument to avCreateNewSection() is actually a handle to the Sections collection, which is obtained by avSections(hData). I added
hSections = avSections(hData)
and put a checkpoint on this statement. To my surprise, when I debug and Step Into the code at this point, I find myself at a line of code in the middle of the function AVSETLBOUND() in AvObjMod.cpp. This makes no sense to me, and doesn't throw any light on the failure of avSections() to return a handle (it returns 0).

Your idea of trying to do this with a C++ function sounds sensible, but I'm not sure if I'm up to the task, I mean within a reasonable amount of time.

I stubbornly persisted a bit longer, and discovered that the debugger was putting me in the wrong function (only about 8 lines from the expected place) because the library was out of synch with the source file AvModObj.cpp, in fact the source had been last saved about 5 min after the library was created, in 2006. Who knows what that signifies, but when I rebuilt the library (after minor surgery on the make file) the debugger started behaving in a more understandable way. Poking around the code I realized that the sequence of handle fetches required to make a new section and give it some properties is this:

hData = avGetObject("/root/dset")
hDataspace = avDataspace(hData)
hSections = avSections(hDataspace)
call avCreateNewSection(hSections, sectionname, hSection)
call avSetStart(hSection, dim, start, status)
! etc.

It works! I can update the data by writing directly to memory, as required. I'm not totally in the clear yet, because there are some funny things happening with the colours that I don't understand, but I'm very happy that it runs without generating errors. I must be almost out of the woods.

And today's my birthday - this is my best present :-)

Colours fixed, all working now. Whew!

Gib