HDF5 export and compare precision

This example shows how to use HDF5 format to export and compare simple precision versus double precision.

Note

This example requires the Premium ServerContext. For more information, see Server context.

Import the dpf-core module and its examples files, and then create a temporary directory.

import os
import tempfile

from ansys.dpf import core as dpf
from ansys.dpf.core import examples
from ansys.dpf.core import operators as ops


dpf.set_default_server_context(dpf.AvailableServerContexts.premium)

tmpdir = tempfile.mkdtemp()

Create the model and get the stresses, displacements, and mesh.

transient = examples.download_transient_result()
model = dpf.Model(transient)

stress = model.results.stress()
displacement = model.results.displacement()
mesh = model.metadata.meshed_region

Create the HDF5 export operator. The HDF5 module should already be loaded.

h5op = ops.serialization.serialize_to_hdf5()
print(h5op)

DPF serialize_to_hdf5 Operator:
  Serialize the inputs in an hdf5 format.
  Inputs:
         file_path [string]: output file path with .h5 extension
         export_floats [bool]: converts double to float to reduce file size (default is true)
         export_flat_vectors [bool]: if true, vectors and matrices data are exported flat (x1,y1,z1,x2,y2,z2..) (default is false)
         data (ellipsis) []: only the data set explicitly to export is exported
  Run the operator to get its result

Connect the correct time scoping to the results operators (stress and displacement).

timeIds = list(range(1, model.metadata.time_freq_support.n_sets + 1))
timeIds

stress.inputs.time_scoping.connect(timeIds)
displacement.inputs.time_scoping.connect(timeIds)

Connect inputs of the HDF5 export operator.

h5op.inputs.data1.connect(stress.outputs)
h5op.inputs.data2.connect(displacement.outputs)
h5op.inputs.data3.connect(mesh)

Export with simple precision.

h5op.inputs.file_path.connect(os.path.join(tmpdir, "dpf_float.h5"))
h5op.run()

Export with double precision.

h5op.inputs.export_floats.connect(False)
h5op.inputs.file_path.connect(os.path.join(tmpdir, "dpf_double.h5"))
h5op.run()

Compare simple precision versus double precision.

float_precision = os.stat(os.path.join(tmpdir, "dpf_float.h5")).st_size
double_precision = os.stat(os.path.join(tmpdir, "dpf_double.h5")).st_size
print(
    f"size with float precision: {float_precision}\n"
    f"size with double precision: {double_precision}"
)

size with float precision: 6703264
size with double precision: 13112464