[tmva][pymva] Deprecate the PyKeras method

README/ReleaseNotes/v640/index.md

@@ -39,6 +39,7 @@ The following people have contributed to this new version:
 * Comparing C++ `nullptr` objects with `None` in Python now raises a `TypeError`, as announced in the ROOT 6.38 release notes. Use truth-value checks like `if not x` or `x is None` instead.
 * The `TGLIncludes.h` and `TGLWSIncludes.h` that were deprecated in ROOT 6.38 and scheduled for removal are gone now. Please include your required headers like `<GL/gl.h>` or `<GL/glu.h>` directly.
 * The GLEW headers (`GL/eglew.h`, `GL/glew.h`, `GL/glxew.h`, and `GL/wglew.h`) that were installed when building ROOT with `builtin_glew=ON` are no longer installed. This is done because ROOT is moving away from GLEW for loading OpenGL extensions.
+* The TMVA `PyKeras` method is deprecated. It was broken by the API changes in Keras 3, released in November 2023 and part of TensorFlow 2.16 or newer. The `PyKeras` method will be removed in ROOT 6.42 (unless an updated implementation for Keras 3 that matches usage, performance and stability requirements will be found unexpectedly).
 
 ## Build System
 

tmva/pymva/CMakeLists.txt

@@ -36,4 +36,7 @@ ROOT_STANDARD_LIBRARY_PACKAGE(PyMVA
     TMVA
 )
 
+# To avoid deprecation warnings during build of ROOT.
+target_compile_definitions(PyMVA PUBLIC PYMVA_BUILDS_ITSELF)
+
 ROOT_ADD_TEST_SUBDIRECTORY(test)

tmva/pymva/src/MethodPyKeras.cxx

@@ -182,6 +182,10 @@ void MethodPyKeras::InitKeras() {
    // initialize first Keras. This is done only here when class has
    // all state variable set from options or read from XML file
    // Import Keras
+   Log() << kWARNING
+         << "The PyKeras TMVA method was deprecated in ROOT 6.40 and will be removed in ROOT 6.42, since it was broken "
+            "by the API changes in Keras 3, released in November 2023 and part of TensorFlow 2.16 or newer."
+         << Endl;
 
    if (fUseTFKeras)
       Log() << kINFO << "Setting up tf.keras" << Endl;

tmva/tmva/inc/TMVA/Types.h

@@ -42,6 +42,8 @@
 
 #include "RtypesCore.h"
 
+#include <ROOT/RConfig.hxx> // for R__DEPRECATED
+
 #include "TString.h"
 
 namespace TMVA {
@@ -100,7 +102,12 @@ namespace TMVA {
          kPyRandomForest ,
          kPyAdaBoost     ,
          kPyGTB          ,
+#ifdef PYMVA_BUILDS_ITSELF
          kPyKeras        ,
+#else
+         kPyKeras
+            R__DEPRECATED(6, 42, "the PyKeras method is dropped since it didn't support Keras 3 (TensorFlow 2.16+)"),
+#endif
          kPyTorch        ,
          kC50            ,
          kRSNNS          ,

tutorials/CMakeLists.txt

@@ -326,7 +326,7 @@ if(NOT TARGET Gui)
 endif()
 
 if (NOT ROOT_tmva_FOUND)
-  list(APPEND tmva_veto machine_learning/*.C machine_learning/*.py machine_learning/envelope/*.C machine_learning/keras/*.C machine_learning/keras/*.py machine_learning/pytorch/*.py )
+  list(APPEND tmva_veto machine_learning/*.C machine_learning/*.py machine_learning/envelope/*.C machine_learning/pytorch/*.py )
 else()
   #copy input data files
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/machine_learning/data/tmva_class_example.root ${CMAKE_CURRENT_BINARY_DIR}/machine_learning/data COPYONLY)
@@ -650,10 +650,6 @@ set (machine_learning-TMVA_SOFIE_RDataFrame_JIT-depends tutorial-machine_learnin
 set (machine_learning-TMVA_SOFIE_Keras_HiggsModel-depends tutorial-machine_learning-TMVA_SOFIE_RDataFrame_JIT)
 set (machine_learning-TMVA_SOFIE_RDataFrame-depends tutorial-machine_learning-TMVA_SOFIE_Keras_HiggsModel)
 set (machine_learning-TMVA_SOFIE_Inference-depends tutorial-machine_learning-TMVA_SOFIE_RDataFrame)
-set (machine_learning-keras-RegressionKeras-depends tutorial-machine_learning-pytorch-RegressionPyTorch-py)
-set (machine_learning-keras-ClassificationKeras-depends tutorial-machine_learning-pytorch-ClassificationPyTorch-py)
-set (machine_learning-keras-ApplicationRegressionKeras-depends tutorial-machine_learning-keras-RegressionKeras-py)
-set (machine_learning-keras-ApplicationClassificationKeras-depends tutorial-machine_learning-keras-ClassificationKeras-py)
 
 #--List long-running tutorials to label them as "longtest"
 set (long_running
@@ -846,11 +842,6 @@ if(ROOT_pyroot_FOUND)
   # Disable tutorial showing connection to the HTCondor service at CERN
   list(APPEND pyveto analysis/dataframe/distrdf004_dask_lxbatch.py)
 
-  if(NOT tmva-pymva)
-    file(GLOB tmva_veto_py RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} machine_learning/keras/*.py)
-    list(APPEND pyveto ${tmva_veto_py})
-  endif()
-
   if (ROOT_KERAS_FOUND)
     set (machine_learning-TMVA_SOFIE_RDataFrame-py-depends tutorial-machine_learning-TMVA_SOFIE_Keras_HiggsModel)
   endif()
@@ -953,7 +944,6 @@ if(ROOT_pyroot_FOUND)
       machine_learning/TMVA_SOFIE_Inference.py
       machine_learning/TMVA_SOFIE_Models.py
       machine_learning/TMVA_SOFIE_RDataFrame.py
-      machine_learning/keras/*.py
   )
   file(GLOB requires_torch   RELATIVE ${CMAKE_CURRENT_SOURCE_DIR}
       machine_learning/pytorch/*.py