Add the Safeguarded EBCC compressor

pyproject.toml

@@ -16,7 +16,7 @@ dependencies = [
     "numcodecs-combinators[xarray]~=0.2.13",
     "numcodecs-observers~=0.1.2",
     "numcodecs-replace==0.1.0",
-    "numcodecs-safeguards==0.1.0b2",
+    "numcodecs-safeguards==0.1.0b5",
     "numcodecs-wasm==0.2.2",
     "numcodecs-wasm-bit-round==0.4.0",
     "numcodecs-wasm-ebcc==0.3.1a0",

src/climatebenchpress/compressor/compressors/safeguarded/__init__.py

@@ -1,5 +1,6 @@
 __all__ = [
     "SafeguardedBitRoundPco",
+    "SafeguardedEbcc",
     "SafeguardedSperr",
     "SafeguardedSz3",
     "SafeguardedZero",
@@ -8,6 +9,7 @@
 ]
 
 from .bitround_pco import SafeguardedBitRoundPco
+from .ebcc import SafeguardedEbcc
 from .sperr import SafeguardedSperr
 from .sz3 import SafeguardedSz3
 from .zero import SafeguardedZero

src/climatebenchpress/compressor/compressors/safeguarded/ebcc.py

@@ -0,0 +1,73 @@
+__all__ = ["SafeguardedEbcc"]
+
+import numcodecs.astype
+import numcodecs_replace
+import numcodecs_safeguards
+import numcodecs_wasm_ebcc
+import numpy as np
+from numcodecs_combinators.stack import CodecStack
+
+from ..abc import Compressor
+
+
+class SafeguardedEbcc(Compressor):
+    """Safeguarded EBCC compressor."""
+
+    name = "safeguarded-ebcc"
+    description = "Safeguarded(EBCC)"
+
+    @staticmethod
+    def abs_bound_codec(error_bound, dtype=None, **kwargs):
+        assert dtype is not None, "dtype must be provided"
+
+        return numcodecs_safeguards.SafeguardedCodec(
+            codec=CodecStack(
+                # EBCC only supports float32 data
+                numcodecs.astype.AsType(
+                    encode_dtype="float32",
+                    decode_dtype=dtype.name,
+                ),
+                # inspired by H5Z-SPERR's treatment of NaN values:
+                # https://github.com/NCAR/H5Z-SPERR/blob/72ebcb00e382886c229c5ef5a7e237fe451d5fb8/src/h5z-sperr.c#L464-L473
+                # https://github.com/NCAR/H5Z-SPERR/blob/72ebcb00e382886c229c5ef5a7e237fe451d5fb8/src/h5zsperr_helper.cpp#L179-L212
+                numcodecs_replace.ReplaceFilterCodec(replacements={np.nan: "nan_mean"}),
+                numcodecs_wasm_ebcc.Ebcc(
+                    # reasonable default recommended by Langwen Huang
+                    base_cr=100,
+                    residual="absolute",
+                    error=error_bound,
+                    chunk_shape="auto",
+                ),
+            ),
+            safeguards=[
+                dict(kind="eb", type="abs", eb=error_bound, equal_nan=True),
+            ],
+        )
+
+    @staticmethod
+    def rel_bound_codec(error_bound, dtype=None, **kwargs):
+        assert dtype is not None, "dtype must be provided"
+
+        return numcodecs_safeguards.SafeguardedCodec(
+            codec=CodecStack(
+                # EBCC only supports float32 data
+                numcodecs.astype.AsType(
+                    encode_dtype="float32",
+                    decode_dtype=dtype.name,
+                ),
+                # inspired by H5Z-SPERR's treatment of NaN values:
+                # https://github.com/NCAR/H5Z-SPERR/blob/72ebcb00e382886c229c5ef5a7e237fe451d5fb8/src/h5z-sperr.c#L464-L473
+                # https://github.com/NCAR/H5Z-SPERR/blob/72ebcb00e382886c229c5ef5a7e237fe451d5fb8/src/h5zsperr_helper.cpp#L179-L212
+                numcodecs_replace.ReplaceFilterCodec(replacements={np.nan: "nan_mean"}),
+                numcodecs_wasm_ebcc.Ebcc(
+                    # reasonable default recommended by Langwen Huang
+                    base_cr=100,
+                    residual="relative",
+                    error=error_bound,
+                    chunk_shape="auto",
+                ),
+            ),
+            safeguards=[
+                dict(kind="eb", type="rel", eb=error_bound, equal_nan=True),
+            ],
+        )