[ITK-users] SimpleITK R Wrapping of ChangeLabel and ChangeMap

[Mathew Guilfoyle]

I am struggling to find the correct way to specify a ChangeMap to supply to the ChangeLabel filter in the R wrapping of SimpleITK.

I can create the filter object but supplying a R list of (vector) pairs of from/to labels causes R to crash.  Looking through the SimpleITK docs the ChangeMap is specified as a std::map<double, double> structure and in the R SWIG file there is a DoubleDoubleMap() function specified which seems to be a mechanism to create the map in R.  However, despite trying various ways of using the DoubleDoubleMap I cannot get it to work.  I can create a DoubleDoubleMap object but then can't supplying the pairs of labels that define the map.  One Python example I came across uses the DoubleDoubleMap like this:

import SimpleITK as silk

changeLabel = sitk.ChangeLabelImageFilter()
changeMap  = sitk.DoubleDoubleMap()

changeMap[0] = 1
changeMap[1] = 2

etc..

Doing the equivalent indexing in R produces the error:

Error: evaluation nested too deeply: infinite recursion / options(expressions=)?
Error during wrapup: evaluation nested too deeply: infinite recursion / options(expressions=)?

Does anyone know how to correctly interact with the DoubleDoubleMap object and/or otherwise specify a change map in R?

Many thanks

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