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

Only one dimension can be -1

Error message

Only one dimension can be -1

What it means

Error "Only one dimension can be -1" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/01-math-foundations/12-tensor-operations/code/tensors.py:105

        if not isinstance(indices, tuple):
            indices = (indices,)
        if len(indices) == len(self._shape):
            return self._data[self._flat_index(indices)]
        raise IndexError("Partial indexing not supported in this basic implementation")

    def __setitem__(self, indices, value):
        if not isinstance(indices, tuple):
            indices = (indices,)
        self._data[self._flat_index(indices)] = value

    def reshape(self, new_shape):
        new_shape = list(new_shape)
        neg_idx = -1
        known_product = 1
        for i, s in enumerate(new_shape):
            if s == -1:
                if neg_idx != -1:
                    raise ValueError("Only one dimension can be -1")
                neg_idx = i
            else:
                known_product *= s

        if neg_idx != -1:
            new_shape[neg_idx] = self.size // known_product

        total = reduce(lambda a, b: a * b, new_shape, 1)
        if total != self.size:
            raise ValueError(
                f"Cannot reshape {self.size} elements into shape {tuple(new_shape)}"
            )

        result = Tensor.__new__(Tensor)
        result._data = self._data[:]
        result._shape = tuple(new_shape)
        result._strides = self._compute_strides(result._shape)
        return result

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/01-math-foundations/12-tensor-operations/code/tensors.py:105 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/3f38f057054d861e. Report an issue: GitHub.