Thanks, Judd. As it happened, I went to C this time, for expediency sake...
Judd Taylor wrote:
> Hi Christopher!
>
> I'm glad to hear you're working with PDL.
>
> There's no built-in direct access member for using the SDgetdimscale()
> function like there is for the SDgetcal() functions. I inherited the
> PDL::IO::HDF code from elsewhere, and I add new features to it on an
> "extreme" basis (meaning if no one asks for the feature, it's not going in).
>
> However, a low-level PerlXS sub is generated for that function, so you
> should be able to get to it. The trick will be preparing the data array
> that will hold the output values.
>
> I'll build this function in for the next release, but since it's part of
> PDL itself now, you'll have to wait for the next stable to be ready to
> go to use that.
>
> In the mean time, I _think_ the below should work. You'll only need to
> know the dataset name and dimension name as input.
>
> Let me know if you have any trouble with it. If you do, then I'll
> probably want to take a look at the HDF file you're using and do some
> further testing here.
>
> -Judd
>
>
>
> my $want_file = "some_hdf_file.hdf";
> my $want_dataset = "some_dataset_name";
> my $want_dim = "some_dim_name";
>
>
> # Make a PDL::IO::HDF::SD object:
> #
> my $hdf = PDL::IO::HDF::SD->new( $want_file );
>
>
> # Get the dim id, based on the stored dimension information that's already in
> # the $hdf object's internals:
> #
> my $dim_id = $hdf->{DATASET}->{$want_dataset}->{DIMS}->{$want_dim}->{DIMID};
>
>
> # We will still need to call the internal _SDdiminfo() to get the number type
> # for the dim scale (it's not already cached, like the dim id). Might as
> # well get the dim size here also.
> # NOTE: these aren't optional vars. We're allocating memory for the C call
> here!
> #
> my $scale_type = 0;
> my $dimname = " "x(PDL::IO::HDF->MAX_NC_NAME+1);
> my $dimsize = 0;
> my $num_type = 0;
> my $n_attrs = 0;
> my $res = PDL::IO::HDF::SD::_SDdiminfo( $dim_id, $dimname, $dimsize,
> $num_type, $n_attrs );
> die "_SDdiminfo() failed!\n"
> if( $res == PDL::IO::HDF->FAIL );
>
>
> # Allocate a PDL variable that can be used as a C array to hold the output
> # dim scale data:
> #
> my $scale = zeroes( $PDL::IO::HDF::SDinvtypeTMAP2->{$num_type}, $dimsize );
>
>
> # Call the internal SDgetdimscale() function:
> #
> $res = PDL::IO::HDF::SD::_SDgetdimscale( $dim_id, $scale );
> die "_SDgetdimscale() failed!\n"
> if( $res == PDL::IO::HDF->FAIL );
>
> # The dimension scale data is now stored in the $scale piddle!
>
>
>
>
>
>
>
>
> On Fri, 2008-03-07 at 15:39 -0500, Christopher Lynnes wrote:
>> Judd,
>> Does PDL::IO::HDF::SD have the getdimscale call? (The man page is
>> silent on this topic...) If so, what is the syntax? Can I give it a
>> dim name or do I need to track down the dimid?
>>
>> Thanks!
>
> --
> ____________________________
> Judd Taylor
> Software Engineer
>
> Orbital Systems, Ltd.
> 3807 Carbon Rd.
> Irving, TX 75038-3415
>
> [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
> (972) 915-3669 x127
>
--
Christopher Lynnes
Code 610.2, NASA/GSFC
301-614-5185
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