ggml-org/llama.cpp b12228

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ggml : implement the backward pass for TRI (#30712)

• ggml: implement the backward pass for TRI

GGML_OP_TRI had no case in the backward switch, so a trainable graph containing it aborted with "unsupported ggml op for backward pass: TRI". The op is linear, so its gradient is masked the same way. The incoming gradient is not necessarily contiguous (the backward of a transpose hands over a view) and ggml_tri requires contiguity, so it is made contiguous first.

test_tri gains a post_transpose variant (out = transpose(tri(a))) that aborts as above without this change.

• ggml : simplify the TRI backward pass

Pass the gradient directly to ggml_tri and drop the transpose test. The existing TRI cases cover the backward pass for contiguous F32 gradients.