rohitg00/ai-engineering-from-scratch · error · ValueError

Invalid permutation {dims} for rank {self.rank}

Error message

Invalid permutation {dims} for rank {self.rank}

What it means

Error "Invalid permutation {dims} for rank {self.rank}" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/01-math-foundations/12-tensor-operations/code/tensors.py:151

        if not new_shape:
            new_shape = ()
        return self.reshape(new_shape)

    def unsqueeze(self, dim):
        if dim < 0:
            dim = len(self._shape) + 1 + dim
        new_shape = list(self._shape)
        new_shape.insert(dim, 1)
        return self.reshape(tuple(new_shape))

    def transpose(self, dim0, dim1):
        perm = list(range(self.rank))
        perm[dim0], perm[dim1] = perm[dim1], perm[dim0]
        return self.permute(perm)

    def permute(self, dims):
        if sorted(dims) != list(range(self.rank)):
            raise ValueError(f"Invalid permutation {dims} for rank {self.rank}")

        new_shape = tuple(self._shape[d] for d in dims)
        result = Tensor.__new__(Tensor)
        result._shape = new_shape
        result._strides = self._compute_strides(new_shape)
        result._data = [0] * self.size

        old_strides = self._strides
        for old_indices in iterproduct(*(range(s) for s in self._shape)):
            new_indices = tuple(old_indices[d] for d in dims)
            old_flat = sum(i * s for i, s in zip(old_indices, old_strides))
            new_flat = sum(
                i * s for i, s in zip(new_indices, result._strides)
            )
            result._data[new_flat] = self._data[old_flat]

        return result

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/01-math-foundations/12-tensor-operations/code/tensors.py:151 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/d3ccf49288e97f67. Report an issue: GitHub.