Signed-off-by: Jakob Weigand [email protected]

Fixes #5886.

Description

When SSIMLoss is called with a tensor of batchsize > 1, SSIMMetric is called for each batch item individually. The result of each call to SSIMMetric is stored in ssim_val. Subsequently, ssim_val is concatenated to ssim_value, which is a collection of all calls to SSIMMetric. Before the concatenation both ssim_val and ssim_value are given a new view of size 1. As ssim_value collects the results of all earlier calls to SSIMMetric, .view(1) raises an error for the second call (as ssim_value has a different absolute size). This commit changes the behavior of the view call, to always use the current size of ssim_value, avoiding this issue but keeping the behavior to concatenate in a single row vector.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.