Return value of function not defined lr_decay

[nedtaylor]

Related to #21, warning when compiling with ifx.

ifx 2023.2.0 20230721

Warning does not occur in compilation of mod_lr_decay.f90. Warning only arises when a module or program uses the learning_rate_decay module (found in file mod_lr_decay.f90).

(base) [ntt203@phy-cdt16 build]$ make
[  0%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_constants.f90.o
...
[ 31%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_input4d_layer.f90.o
[ 32%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_lr_decay.f90.o
[ 33%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_maxpool2d_layer.f90.o
...
[ 37%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_optimiser.f90.o
/tmp/ifx16713391811BbRBG/ifxItJuj9.i90: warning #6178: The return value of this FUNCTION has not been defined.   [LR_DECAY]
[ 37%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_network.f90.o
...
[ 40%] Building Fortran object CMakeFiles/athena.dir/src/athena.f90.o
/tmp/ifx0214165105ctfpsh/ifx9j5FEk.i90: warning #6178: The return value of this FUNCTION has not been defined.   [LR_DECAY]
[ 41%] Building Fortran object CMakeFiles/athena.dir/src/lib/mod_base_layer_sub.f90.o
...
[ 44%] Linking Fortran static library libathena.a
[ 44%] Built target athena

[nedtaylor]

This seems to have no effect on the unit tests. The code seems to work fine. They are warnings and not compilation errors.

The odd thing is that, from what I can see, the file format is identical to that of the layer_setup() functions found in all the layer modules.

[nedtaylor]

This appears to be a compiler issue, not a code issue. This won't be fixed by me then (unless new information comes to light).

https://fortran-lang.discourse.group/t/the-return-value-of-this-function-has-not-been-defined/7858