TSStandardize on subset of variables

[meanpenguin]

No sure if it's a bug or I'm not using it as intended.... I need standardize some of the columns

TSStandardize seems like it can take a list of column numbers to standardize

in

    def setups(self, dl: DataLoader):
        ...
        if self.by_var and is_listy(self.by_var):
        ...

Since I don't want the first column standardized, calling

   batch_tfms = TSStandardize(by_sample=False, by_var=[1,2,3] , verbose=True)

Get the following error

/usr/local/lib/python3.7/dist-packages/fastcore/dispatch.py in __call__(self, *args, **kwargs)
    116         elif self.inst is not None: f = MethodType(f, self.inst)
    117         elif self.owner is not None: f = MethodType(f, self.owner)
--> 118         return f(*args, **kwargs)
    119 
    120     def __get__(self, inst, owner):

/usr/local/lib/python3.7/dist-packages/tsai/data/preprocessing.py in encodes(self, o)
    131                 self.mean = torch_nanmean(o, dim=self.axes, keepdim=self.axes!=())
    132                 self.std = torch.clamp_min(torch_nanstd(o, dim=self.axes, keepdim=self.axes!=()), self.eps)
--> 133         return (o - self.mean) / self.std
    134 
    135     def decodes(self, o:TSTensor):

/usr/local/lib/python3.7/dist-packages/fastai/torch_core.py in __torch_function__(self, func, types, args, kwargs)
    338         convert=False
    339         if _torch_handled(args, self._opt, func): convert,types = type(self),(torch.Tensor,)
--> 340         res = super().__torch_function__(func, types, args=args, kwargs=kwargs)
    341         if convert: res = convert(res)
    342         if isinstance(res, TensorBase): res.set_meta(self, as_copy=True)

/usr/local/lib/python3.7/dist-packages/torch/_tensor.py in __torch_function__(cls, func, types, args, kwargs)
   1021 
   1022         with _C.DisableTorchFunction():
-> 1023             ret = func(*args, **kwargs)
   1024             return _convert(ret, cls)
   1025 

RuntimeError: The size of tensor a (2) must match the size of tensor b (6) at non-singleton dimension 1

See linked Notebook
https://colab.research.google.com/drive/1Nf5GVA4oPM32wjl1STVIOEIn2bHCR5J0?usp=sharing

[oguiza]

I created an issue to address this. It's more an enhancement than a proper issue. It's been implemented as #141.