A bug when there is no point satisfy disp < maxdisp

[youmi-zym]

Hi: I find there are some images' disparity of SceneFlow are bigger than maxdisp,

mask = disp_true < args.maxdisp
mask.detach_()

mask is all zero here, there will be a error when calculating loss, and it can't be backward.

An example:

The code will run well with batch-size bigger than 1, but batch-size=1 will lead this bug

my advice is before model forward, check wether mask is all 0:

mask = (disp_true < args.max_disp)
mask = mask.detach().type_as(disp_true)
if mask.sum() < 1.0:
    continue

[JiaRenChang]

Hi, @youmi-zym Thank you. I will modified it.