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Merged
bdestombe merged 1 commit into from
Mar 13, 2024
Merged

Update attributes_encodings.py #332

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12 changes: 8 additions & 4 deletions nlmod/dims/attributes_encodings.py
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Original file line number Diff line number Diff line change
Expand Up @@ -229,9 +229,13 @@ def get_encodings(

def compute_scale_and_offset(min_value, max_value):
"""
Computes the scale_factor and offset for the dataset using a min_value and max_value,
and int16. Useful for maximizing the compression of a dataset.

Reduce precision of the dataset by storing it as int16 and thereby reducing the precision.

Computes the scale_factor and offset for the dataset using a min_value and max_value to
transform the range of the dataset to the range of valid int16 values. The packed value
is computed as:
packed_value = (unpacked_value - add_offset) / scale_factor

Parameters
----------
min_value : float
Expand All @@ -250,7 +254,7 @@ def compute_scale_and_offset(min_value, max_value):
# from -32766 to 32767, because -32767 is the default fillvalue.
width = 32766 + 32767
scale_factor = (max_value - min_value) / width
add_offset = 1.0 + scale_factor * (width - 1) / 2
add_offset = max_value - scale_factor * 32767
return scale_factor, add_offset


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