Trait zarrs::array::codec::ArrayPartialDecoderTraits
source · pub trait ArrayPartialDecoderTraits: Send + Sync {
// Required methods
fn data_type(&self) -> &DataType;
fn partial_decode_opt(
&self,
array_subsets: &[ArraySubset],
options: &CodecOptions,
) -> Result<Vec<ArrayBytes<'_>>, CodecError>;
// Provided method
fn partial_decode(
&self,
array_subsets: &[ArraySubset],
) -> Result<Vec<ArrayBytes<'_>>, CodecError> { ... }
}
Expand description
Partial array decoder traits.
Required Methods§
sourcefn partial_decode_opt(
&self,
array_subsets: &[ArraySubset],
options: &CodecOptions,
) -> Result<Vec<ArrayBytes<'_>>, CodecError>
fn partial_decode_opt( &self, array_subsets: &[ArraySubset], options: &CodecOptions, ) -> Result<Vec<ArrayBytes<'_>>, CodecError>
Explicit options version of partial_decode
.
Provided Methods§
sourcefn partial_decode(
&self,
array_subsets: &[ArraySubset],
) -> Result<Vec<ArrayBytes<'_>>, CodecError>
fn partial_decode( &self, array_subsets: &[ArraySubset], ) -> Result<Vec<ArrayBytes<'_>>, CodecError>
Partially decode a chunk with default codec options.
If the inner input_handle
is a bytes decoder and partial decoding returns None
, then the array subsets have the fill value.
Use partial_decode_opt
to control codec options.
§Errors
Returns CodecError
if a codec fails or an array subset is invalid.
Examples found in repository?
examples/sharded_array_write_read.rs (line 139)
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fn sharded_array_write_read() -> Result<(), Box<dyn std::error::Error>> {
use zarrs::{
array::{
codec::{self, array_to_bytes::sharding::ShardingCodecBuilder},
DataType, FillValue,
},
array_subset::ArraySubset,
node::Node,
storage::store,
};
use rayon::prelude::{IntoParallelIterator, ParallelIterator};
use std::sync::Arc;
// Create a store
// let path = tempfile::TempDir::new()?;
// let mut store: ReadableWritableListableStorage = Arc::new(store::FilesystemStore::new(path.path())?);
// let mut store: ReadableWritableListableStorage = Arc::new(store::FilesystemStore::new("tests/data/sharded_array_write_read.zarr")?);
let mut store: ReadableWritableListableStorage = Arc::new(store::MemoryStore::new());
if let Some(arg1) = std::env::args().collect::<Vec<_>>().get(1) {
if arg1 == "--usage-log" {
let log_writer = Arc::new(std::sync::Mutex::new(
// std::io::BufWriter::new(
std::io::stdout(),
// )
));
let usage_log = Arc::new(UsageLogStorageTransformer::new(log_writer, || {
chrono::Utc::now().format("[%T%.3f] ").to_string()
}));
store = usage_log
.clone()
.create_readable_writable_listable_transformer(store);
}
}
// Create a group
let group_path = "/group";
let mut group = zarrs::group::GroupBuilder::new().build(store.clone(), group_path)?;
// Update group metadata
group
.attributes_mut()
.insert("foo".into(), serde_json::Value::String("bar".into()));
// Write group metadata to store
group.store_metadata()?;
// Create an array
let array_path = "/group/array";
let shard_shape = vec![4, 8];
let inner_chunk_shape = vec![4, 4];
let mut sharding_codec_builder =
ShardingCodecBuilder::new(inner_chunk_shape.as_slice().try_into()?);
sharding_codec_builder.bytes_to_bytes_codecs(vec![
#[cfg(feature = "gzip")]
Box::new(codec::GzipCodec::new(5)?),
]);
let array = zarrs::array::ArrayBuilder::new(
vec![8, 8], // array shape
DataType::UInt16,
shard_shape.try_into()?,
FillValue::from(0u16),
)
.array_to_bytes_codec(Box::new(sharding_codec_builder.build()))
.dimension_names(["y", "x"].into())
// .storage_transformers(vec![].into())
.build(store.clone(), array_path)?;
// Write array metadata to store
array.store_metadata()?;
// The array metadata is
println!(
"The array metadata is:\n{}\n",
serde_json::to_string_pretty(&array.metadata()).unwrap()
);
// Write some shards (in parallel)
(0..2).into_par_iter().try_for_each(|s| {
let chunk_grid = array.chunk_grid();
let chunk_indices = vec![s, 0];
if let Some(chunk_shape) = chunk_grid.chunk_shape(&chunk_indices, array.shape())? {
let chunk_array = ndarray::ArrayD::<u16>::from_shape_fn(
chunk_shape
.iter()
.map(|u| u.get() as usize)
.collect::<Vec<_>>(),
|ij| {
(s * chunk_shape[0].get() * chunk_shape[1].get()
+ ij[0] as u64 * chunk_shape[1].get()
+ ij[1] as u64) as u16
},
);
array.store_chunk_ndarray(&chunk_indices, chunk_array)
} else {
Err(zarrs::array::ArrayError::InvalidChunkGridIndicesError(
chunk_indices.to_vec(),
))
}
})?;
// Read the whole array
let subset_all = ArraySubset::new_with_shape(array.shape().to_vec()); // the center 4x2 region
let data_all = array.retrieve_array_subset_ndarray::<u16>(&subset_all)?;
println!("The whole array is:\n{data_all}\n");
// Read a shard back from the store
let shard_indices = vec![1, 0];
let data_shard = array.retrieve_chunk_ndarray::<u16>(&shard_indices)?;
println!("Shard [1,0] is:\n{data_shard}\n");
// Read an inner chunk from the store
let subset_chunk_1_0 = ArraySubset::new_with_ranges(&[4..8, 0..4]);
let data_chunk = array.retrieve_array_subset_ndarray::<u16>(&subset_chunk_1_0)?;
println!("Chunk [1,0] is:\n{data_chunk}\n");
// Read the central 4x2 subset of the array
let subset_4x2 = ArraySubset::new_with_ranges(&[2..6, 3..5]); // the center 4x2 region
let data_4x2 = array.retrieve_array_subset_ndarray::<u16>(&subset_4x2)?;
println!("The middle 4x2 subset is:\n{data_4x2}\n");
// Decode inner chunks
// In some cases, it might be preferable to decode inner chunks in a shard directly.
// If using the partial decoder, then the shard index will only be read once from the store.
let partial_decoder = array.partial_decoder(&[0, 0])?;
let inner_chunks_to_decode = vec![
ArraySubset::new_with_start_shape(vec![0, 0], inner_chunk_shape.clone())?,
ArraySubset::new_with_start_shape(vec![0, 4], inner_chunk_shape.clone())?,
];
let decoded_inner_chunks_bytes = partial_decoder.partial_decode(&inner_chunks_to_decode)?;
println!("Decoded inner chunks:");
for (inner_chunk_subset, decoded_inner_chunk) in
std::iter::zip(inner_chunks_to_decode, decoded_inner_chunks_bytes)
{
let ndarray = bytes_to_ndarray::<u16>(
&inner_chunk_shape,
decoded_inner_chunk.into_fixed()?.into_owned(),
)?;
println!("{inner_chunk_subset}\n{ndarray}\n");
}
// Show the hierarchy
let node = Node::open(&store, "/").unwrap();
let tree = node.hierarchy_tree();
println!("The Zarr hierarchy tree is:\n{}", tree);
println!(
"The keys in the store are:\n[{}]",
store.list().unwrap_or_default().iter().format(", ")
);
Ok(())
}