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https://issues.apache.org/jira/browse/SIS-384?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Desruisseaux updated SIS-384:
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Fix Version/s: 1.5
> (Affine → Passthrough → Affine) should be simplified as (Affine →
> Passthrough) or (Passthrough → Affine)
> --------------------------------------------------------------------------------------------------------
>
> Key: SIS-384
> URL: https://issues.apache.org/jira/browse/SIS-384
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: Referencing
> Affects Versions: 0.5, 0.6, 0.7, 0.8, 1.0, 1.1, 1.2, 1.3, 1.4
> Reporter: Martin Desruisseaux
> Priority: Minor
> Labels: performance
> Fix For: 1.5
>
>
> Below is an example of concatenated math transform. An "Affine" operation
> appears twice: before and after the "Passthrough" operation:
> {noformat}
> Concat_MT[
> Param_MT["Affine",
> Parameter["num_row", 5],
> Parameter["num_col", 5],
> Parameter["elt_0_0", 0.025],
> Parameter["elt_0_4", 3.0125],
> Parameter["elt_1_1", -0.025],
> Parameter["elt_1_4", 44.9875]],
> PassThrough_MT[2, 1, Param_MT["Interpolation 1D",
> Parameter["values", {2.0, 10.0, 20.0, 35.0, 50.0, 75.0, 100.0}]]],
> Param_MT["Affine",
> Parameter["num_row", 5],
> Parameter["num_col", 5],
> Parameter["elt_3_3", 3600000.0],
> Parameter["elt_3_4", 1.5127128E12]]]
> {noformat}
> The last "Affine" operates only on passthrough coordinates. Consequently it
> could be moved before the "Passthrouh" operation, which would allow
> concatenation with the first "Affine" operation. It should not change the
> operation result, but can improve performance.
> This optimization is possible only for "Affine" that operate only on
> pass-through coordinates. If the last "Affine" does not comply with this
> condition, maybe the first "Affine" does. So we will need to test both.
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