jax-ml/jax · error · TypeError

dynamic_slice: unrecognized index {pidx.index}

Error message

dynamic_slice: unrecognized index {pidx.index}

What it means

Second catch-all TypeError in to_dynamic_slice, raised in the start-index-building loop when an index type passed validation categorization but has no dynamic-slice start contribution. Indicates an internally unrecognized IndexType.

Source

Thrown at jax/_src/numpy/indexing.py:562

        axis, = pidx.consumed_axes
        size = self.shape[axis]
        start, stop, stride = pidx.index.indices(size)
        assert stride in [-1, 1]  # validated above
        if stride < 0:
          new_start = stop + 1 + abs(start - stop - 1) % abs(stride)
          start_indices.append(new_start)
          slice_sizes.append(max(0, start + 1 - new_start))
          rev_axes.append(axis)
        else:
          start_indices.append(start)
          slice_sizes.append(max(0, stop - start))
      elif pidx.typ == IndexType.DYNAMIC_SLICE:
        assert isinstance(pidx.index, indexing.Slice)
        start_indices.append(pidx.index.start)
        slice_sizes.append(pidx.index.size)
        trivial_slicing = False
      else:
        raise TypeError(f"dynamic_slice: unrecognized index {pidx.index}")

    if len(start_indices) > 1:
      # We must be careful with dtypes because dynamic_slice requires all
      # start indices to have matching types.
      dt = lax_utils.int_dtype_for_shape(self.shape, signed=True)
      start_indices = [lax.convert_element_type(i, dt) for i in start_indices]

    return _DynamicSliceIndexer(
      start_indices=start_indices,
      slice_sizes=slice_sizes,
      rev_axes=rev_axes,
      squeeze_axes=squeeze_axes,
      newaxis_dims=newaxis_dims,
      normalize_indices=normalize_indices,
      trivial_slicing=trivial_slicing,
    )

  def is_advanced_int_indexer(self):

View on GitHub (pinned to 1e1c6a8fc0)

Solutions

1. Use only standard index types (int, slice, None, ..., scalar tracers)
2. Check for a JAX version mismatch between jax and jaxlib
3. File an issue with a minimal reproducer if using supported constructs

When it happens

Trigger: An index type that is not INTEGER/ELLIPSIS/NONE/SLICE/DYNAMIC_SLICE/ARRAY/BOOLEAN reaches the second loop of to_dynamic_slice — essentially an internal inconsistency or new index kind without dynamic support.

Common situations: Extending JAX with custom index types; mismatched JAX internal versions; extremely rare for end users.

Related errors

• dynamic_slice: only unit steps supported in slice. Got {pidx
• dynamic_slice: only scalar indices allowed. Got index of typ
• dynamic_slice: indices must be scalars or slices. Got index
• dynamic_slice: unrecognized index {pidx.index} at position {
• Value of type {type(self)} is not convertible to integer ind

AI-assisted analysis of jax-ml/jax@1e1c6a8fc0 (2026-08-27). Data as JSON: /api/errors/578efd6ca2c9f217. Report an issue: GitHub.