API Reference

The zfp gem exposes three layers of API. Choose the one that fits your use case.

API	Description	When to use
Module methods	Zfp.compress, Zfp.decompress, Zfp.pack, Zfp.unpack	One-off operations; the easy path
Zfp::Codec	Reusable object with a fixed configuration	Many arrays with the same type/shape/mode
Errors	Zfp::Error and subclasses	Error handling
Internals	Zfp::Field, Zfp::Stream, Zfp::Packer, Zfp::FFI	Understanding the implementation

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Quick Reference

# Module methods
Zfp.compress(data, type:, shape:, mode:, **params)   → String (bytes)
Zfp.decompress(bytes, type:, shape:, mode:, numo: false, **params)  → Array | Numo::NArray
Zfp.pack(data, type: nil, shape: nil, mode:, **params)  → String (bytes with 32-byte header)
Zfp.unpack(bytes)  → Array | Numo::NArray

# Codec
codec = Zfp::Codec.new(type:, shape:, mode:, numo: false, **params)
codec.compress(data)     → String (bytes)
codec.decompress(bytes)  → Array | Numo::NArray
codec.pack(data)         → String (bytes with 32-byte header)

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Parameter Reference

type: — scalar type

Symbol	Ruby input	FFI type	Bytes/element
:float	Array of Float or Numo::SFloat	32-bit IEEE 754	4
:double	Array of Float or Numo::DFloat	64-bit IEEE 754	8
:int32	Array of Integer or Numo::Int32	32-bit signed	4
:int64	Array of Integer or Numo::Int64	64-bit signed	8

shape: — array dimensions

An Array of 1–4 positive integers whose product equals the element count:

shape: [1000]           # 1-D, 1000 elements
shape: [50, 252]        # 2-D, 12,600 elements
shape: [10, 30, 252]    # 3-D, 75,600 elements
shape: [4, 8, 16, 16]  # 4-D, 8,192 elements

mode: — compression mode

Symbol	Required params	Description
:reversible	(none)	Lossless, bit-exact
:fixed_rate	rate: Float	Fixed bits per value
:fixed_precision	precision: Integer	Fixed significant bits
:fixed_accuracy	tolerance: Float	Absolute error bound

numo: — Numo output flag

When true, decompress returns a Numo::NArray instead of a Ruby Array. The Numo type is inferred from type:.