OneHot broken? - Githubissues

Dear Keops developers,

Together with @amic-github, we have been trying to implement a reduction formula which involves a one_hot LazyTensor but we got a very strange error which makes me think that something has been broken in a recent update.

The following code

import torch
from pykeops.torch import LazyTensor

use_cuda = torch.cuda.is_available()
dtype = torch.cuda.FloatTensor if use_cuda else torch.FloatTensor

x=torch.tensor([0.,5.,10.]).type(dtype).reshape(3,1)
xi=LazyTensor(x[:,None,:])
y = xi.one_hot(42)
y.sum(1)

returns the following error on Google Colab

[KeOps] Compiling cuda jit compiler engine ... OK
[pyKeOps] Compiling nvrtc binder for python ... OK
OneHot

---------------------------------------------------------------------------

NameError                                 Traceback (most recent call last)

[<ipython-input-2-3a5c9c813431>](https://localhost:8080/#) in <module>()
      8 xi=LazyTensor(x[:,None,:])
      9 y = xi.one_hot(42)
---> 10 y.sum(1)

12 frames

[/usr/local/lib/python3.7/dist-packages/pykeops/common/lazy_tensor.py](https://localhost:8080/#) in sum(self, axis, dim, **kwargs)
   1798             return self.unary("Sum", dimres=1)
   1799         else:
-> 1800             return self.reduction("Sum", axis=axis, **kwargs)
   1801 
   1802     def sum_reduction(self, axis=None, dim=None, **kwargs):

[/usr/local/lib/python3.7/dist-packages/pykeops/common/lazy_tensor.py](https://localhost:8080/#) in reduction(self, reduction_op, other, opt_arg, axis, dim, call, is_complex, **kwargs)
    753             )
    754         if call and len(res.symbolic_variables) == 0 and res._dtype is not None:
--> 755             return res()
    756         else:
    757             return res

[/usr/local/lib/python3.7/dist-packages/pykeops/common/lazy_tensor.py](https://localhost:8080/#) in __call__(self, *args, **kwargs)
    935             args = (self.other.variables[0],)
    936 
--> 937         return self.callfun(*args, *self.variables, **self.kwargs)
    938 
    939     def __str__(self):

[/usr/local/lib/python3.7/dist-packages/pykeops/torch/generic/generic_red.py](https://localhost:8080/#) in __call__(self, backend, device_id, ranges, out, *args)
    634             ny,
    635             out,
--> 636             *args
    637         )
    638 

[/usr/local/lib/python3.7/dist-packages/pykeops/torch/generic/generic_red.py](https://localhost:8080/#) in forward(ctx, formula, aliases, backend, dtype, device_id_request, ranges, optional_flags, rec_multVar_highdim, nx, ny, out, *args)
     87             dtype,
     88             "torch",
---> 89             optional_flags,
     90         ).import_module()
     91 

[/usr/local/lib/python3.7/dist-packages/keopscore/utils/Cache.py](https://localhost:8080/#) in __call__(self, *args)
     66                     self.library[str_id] = self.cls(params, fast_init=True)
     67                 else:
---> 68                     obj = self.cls(*args)
     69                     self.library_params[str_id] = obj.params
     70                     self.library[str_id] = obj

[/usr/local/lib/python3.7/dist-packages/pykeops/common/keops_io/LoadKeOps_nvrtc.py](https://localhost:8080/#) in __init__(self, fast_init, *args)
     13 class LoadKeOps_nvrtc_class(LoadKeOps):
     14     def __init__(self, *args, fast_init=False):
---> 15         super().__init__(*args, fast_init=fast_init)
     16 
     17     def init_phase2(self):

[/usr/local/lib/python3.7/dist-packages/pykeops/common/keops_io/LoadKeOps.py](https://localhost:8080/#) in __init__(self, fast_init, *args)
     16             self.params = args[0]
     17         else:
---> 18             self.init(*args)
     19         self.dimout = self.params.dim
     20         self.tagIJ = self.params.tagI

[/usr/local/lib/python3.7/dist-packages/pykeops/common/keops_io/LoadKeOps.py](https://localhost:8080/#) in init(self, tagCPUGPU, tag1D2D, tagHostDevice, use_ranges, device_id_request, formula, aliases, nargs, dtype, lang, optional_flags)
    139             tag1D2D,
    140             self.params.use_half,
--> 141             device_id_request,
    142         )
    143 

[/usr/local/lib/python3.7/dist-packages/keopscore/utils/Cache.py](https://localhost:8080/#) in __call__(self, *args)
     25         str_id = "".join(list(str(arg) for arg in args)) + str(env_param)
     26         if not str_id in self.library:
---> 27             self.library[str_id] = self.fun(*args)
     28         return self.library[str_id]
     29 

[/usr/local/lib/python3.7/dist-packages/keopscore/get_keops_dll.py](https://localhost:8080/#) in get_keops_dll_impl(map_reduce_id, red_formula_string, enable_chunks, enable_finalchunks, mul_var_highdim, aliases, *args)
     91         set_enable_finalchunk(enable_finalchunks)
     92         set_mult_var_highdim(mul_var_highdim)
---> 93         red_formula = GetReduction(red_formula_string, aliases)
     94         if use_final_chunks(red_formula) and map_reduce_id != "GpuReduc2D":
     95             use_chunk_mode = 2

[/usr/local/lib/python3.7/dist-packages/keopscore/formulas/GetReduction.py](https://localhost:8080/#) in __new__(self, red_formula_string, aliases)
     25                     varname, var = alias.split("=")
     26                     aliases_dict[varname] = eval(var)
---> 27             reduction = eval(red_formula_string, globals(), aliases_dict)
     28             GetReduction.library[string_id_hash] = reduction
     29             return reduction

/usr/local/lib/python3.7/dist-packages/keopscore/formulas/GetReduction.py in <module>()

NameError: name 'OneHot' is not defined

Note also that the answer of @jeanfeydy in https://github.com/getkeops/keops/issues/24#issuecomment-536018052 which involves the one_hot function returns the same error (but I guess it did work back in 2019).

What do you think?

Thanks!

getkeops / keops

OneHot broken? #263