CompressorZFP

The CompressorZFP Operator is compressor that uses a lossy but optionally error-bounded compression to achieve high compression ratios.

ZFP provides compressed-array classes that support high throughput read and write random access to individual array elements. ZFP also supports serial and parallel (OpenMP and CUDA) compression of whole arrays, e.g., for applications that read and write large data sets to and from disk.

ADIOS2 provides a CompressorZFP operator that lets you compress an decompress variables. Below there is an example of how to invoke CompressorZFP operator:

adios2::IO io = adios.DeclareIO("Output");
auto ZFPOp    = adios.DefineOperator("CompressorZFP", adios2::ops::LossyZFP);

auto var_r32 = io.DefineVariable<float>("r32", shape, start, count);
var_r32.AddOperation(ZFPOp, {{adios2::ops::zfp::key::rate, rate}});

CompressorZFP Specific parameters

The CompressorZFP operator accepts the following operator specific parameters:

`CompressorZFP` available parameters
`accuracy`	Fixed absolute error tolerance
`rate`	Fixed number of bits in a compression unit
`precision`	Fixed number of uncompressed bits per value
`backend`	Backend device: `cuda` `omp` `serial`

CompressorZFP Execution Policy

CompressorZFP can run in multiple backend devices: GPUs (CUDA), OpenMP, and in the host CPU. By default CompressorZFP will choose its backend following the above order upon the availability of the device adapter.

Exceptionally, if its corresponding ADIOS2 variable contains a CUDA memory address, this is a CUDA buffer, the CUDA backend will be called if available.

In any case, the user can manually set the backend using the ZFPOperator specific parameter backend.