CarpetIOHDF5: support per-variable output compression levels

Implement variable-specific output request option 'compression_level'
so that users can specify eg.

  IOHDF5::compression_level = 1
  IOHDF5::out_vars          = "admbase::metric
                               admconstraints::hamiltonian
                               admbase::lapse{ compression_level = 0 }"

to request HDF5 dataset compression for every output variable except for the
lapse.

This modification also requires an update of thorn CactusBase/IOUtil.

darcs-hash:20061117132206-776a0-0e1d07a85cf206fa262a94fd0dd63c6f27e50fa2.gz

2 files changed, 22 insertions, 9 deletions

diff --git a/Carpet/CarpetIOHDF5/doc/documentation.tex b/Carpet/CarpetIOHDF5/doc/documentation.tex
index c0ca6b0d9..4f449c2fd 100644
--- a/Carpet/CarpetIOHDF5/doc/documentation.tex
+++ b/Carpet/CarpetIOHDF5/doc/documentation.tex
@@ -102,12 +102,13 @@ Parameters to control the \ThisThorn\ I/O method are:
 
         Each group/variable name can have an option string attached in which you
         can specify a different output frequency for that individual variable,
-	a set of individual refinement levels to be output, or an individual
-        output mode, e.g.
+	a set of individual refinement levels to be output, the compression
+        level, or an individual output mode, e.g.
 \begin{verbatim}
   IOHDF5::out_vars = "wavetoy::phi{ out_every = 4 refinement_levels = { 1 2 } }"
 \end{verbatim}
-        Option strings currently supported by \ThisThorn\ are: {\tt out\_every, out\_unchunked}, and {\tt refinement\_levels}.
+        Option strings currently supported by \ThisThorn\ are: {\tt out\_every,
+        out\_unchunked}, {\tt refinement\_levels}, and {\tt compression\_level}.
 
   \item {\tt IOHDF5::out\_dir}\\
         The directory in which to place the \ThisThorn\ output files.
@@ -125,6 +126,9 @@ Parameters to control the \ThisThorn\ I/O method are:
         with increasing values requesting higher compression rates (at the cost
         of additional runtime for outputting HDF5 data); a value of zero
         (which is the default setting for this parameter) disables compression.
+        The output compression level can also be set
+        for individual variables using the {\tt compression\_level} option in
+        an option string appended to the {\tt IOHDF5::out\_vars} parameter.
 
   \item {\tt IO::out\_single\_precision (steerable)}\\
         whether to output double-precision data in single precision
diff --git a/Carpet/CarpetIOHDF5/src/Output.cc b/Carpet/CarpetIOHDF5/src/Output.cc
index a0367ba58..6d3da697b 100644
--- a/Carpet/CarpetIOHDF5/src/Output.cc
+++ b/Carpet/CarpetIOHDF5/src/Output.cc
@@ -140,9 +140,12 @@ int WriteVarUnchunked (const cGH* const cctkGH,
         // enable compression if requested
         hid_t plist;
         HDF5_ERROR (plist = H5Pcreate (H5P_DATASET_CREATE));
-        if (compression_level) {
+        const int compression_lvl = request->compression_level >= 0 ?
+                                    request->compression_level :
+                                    compression_level;
+        if (compression_lvl) {
           HDF5_ERROR (H5Pset_chunk (plist, group.dim, shape));
-          HDF5_ERROR (H5Pset_deflate (plist, compression_level));
+          HDF5_ERROR (H5Pset_deflate (plist, compression_lvl));
         }
         HDF5_ERROR (dataset = H5Dcreate (outfile, datasetname.str().c_str(),
                                          filedatatype, dataspace, plist));
@@ -390,9 +393,12 @@ int WriteVarChunkedSequential (const cGH* const cctkGH,
           hid_t plist, dataspace, dataset;
           HDF5_ERROR (plist = H5Pcreate (H5P_DATASET_CREATE));
           // enable compression if requested
-          if (compression_level) {
+          const int compression_lvl = request->compression_level >= 0 ?
+                                      request->compression_level :
+                                      compression_level;
+          if (compression_lvl) {
             HDF5_ERROR (H5Pset_chunk (plist, group.dim, shape));
-            HDF5_ERROR (H5Pset_deflate (plist, compression_level));
+            HDF5_ERROR (H5Pset_deflate (plist, compression_lvl));
           }
           HDF5_ERROR (dataspace = H5Screate_simple (group.dim, shape, NULL));
           HDF5_ERROR (dataset = H5Dcreate (outfile, datasetname.str().c_str(),
@@ -535,9 +541,12 @@ int WriteVarChunkedParallel (const cGH* const cctkGH,
       hid_t plist, dataspace, dataset;
       HDF5_ERROR (plist = H5Pcreate (H5P_DATASET_CREATE));
       // enable compression if requested
-      if (compression_level) {
+      const int compression_lvl = request->compression_level >= 0 ?
+                                  request->compression_level :
+                                  compression_level;
+      if (compression_lvl) {
         HDF5_ERROR (H5Pset_chunk (plist, group.dim, shape));
-        HDF5_ERROR (H5Pset_deflate (plist, compression_level));
+        HDF5_ERROR (H5Pset_deflate (plist, compression_lvl));
       }
       HDF5_ERROR (dataspace = H5Screate_simple (group.dim, shape, NULL));
       HDF5_ERROR (dataset = H5Dcreate (outfile, datasetname.str().c_str(),