 equivalent function for "imfilter" and "filter2" in torch?

Hi,
I am trying to write these matlab code in torch, but I do not know what is the true function to do this? 


```
> mu1 = filter2(win, img1, 'valid');
> filtered_im1 = imfilter(im1, downsample_filter, 'symmetric', 'same');
> 
```

 I would really appreciate it if anyone can tell how to do this. 