issue_comments: 690367604

The numpy example is fixed but the dask rechunked example is still broken.

python a = dask.array.ones((10,5), chunks=(1,3)) dask.optimize(xr.DataArray(a))[0].compute() # works dask.optimize(xr.DataArray(a).chunk(5))[0].compute() # error

``` IndexError Traceback (most recent call last) <ipython-input-8-5663bc8bc82a> in <module> ----> 1 dask.optimize(xr.DataArray(a).chunk(5))[0].compute()

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/xarray/core/dataarray.py in compute(self, kwargs) 838 """ 839 new = self.copy(deep=False) --> 840 return new.load(kwargs) 841 842 def persist(self, **kwargs) -> "DataArray":

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/xarray/core/dataarray.py in load(self, kwargs) 812 dask.array.compute 813 """ --> 814 ds = self._to_temp_dataset().load(kwargs) 815 new = self._from_temp_dataset(ds) 816 self._variable = new._variable

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/xarray/core/dataset.py in load(self, kwargs) 656 657 # evaluate all the dask arrays simultaneously --> 658 evaluated_data = da.compute(*lazy_data.values(), kwargs) 659 660 for k, data in zip(lazy_data, evaluated_data):

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/base.py in compute(args, kwargs) 445 postcomputes.append(x.dask_postcompute()) 446 --> 447 results = schedule(dsk, keys, kwargs) 448 return repack([f(r, a) for r, (f, a) in zip(results, postcomputes)]) 449

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/threaded.py in get(dsk, result, cache, num_workers, pool, **kwargs) 74 pools[thread][num_workers] = pool 75 ---> 76 results = get_async( 77 pool.apply_async, 78 len(pool._pool),

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/local.py in get_async(apply_async, num_workers, dsk, result, cache, get_id, rerun_exceptions_locally, pack_exception, raise_exception, callbacks, dumps, loads, **kwargs) 484 _execute_task(task, data) # Re-execute locally 485 else: --> 486 raise_exception(exc, tb) 487 res, worker_id = loads(res_info) 488 state["cache"][key] = res

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/local.py in reraise(exc, tb) 314 if exc.traceback is not tb: 315 raise exc.with_traceback(tb) --> 316 raise exc 317 318

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/local.py in execute_task(key, task_info, dumps, loads, get_id, pack_exception) 220 try: 221 task, data = loads(task_info) --> 222 result = _execute_task(task, data) 223 id = get_id() 224 result = dumps((result, id))

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/core.py in _execute_task(arg, cache, dsk) 119 # temporaries by their reference count and can execute certain 120 # operations in-place. --> 121 return func(*(_execute_task(a, cache) for a in args)) 122 elif not ishashable(arg): 123 return arg

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/array/core.py in concatenate3(arrays) 4407 if not ndim: 4408 return arrays -> 4409 chunks = chunks_from_arrays(arrays) 4410 shape = tuple(map(sum, chunks)) 4411

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/array/core.py in chunks_from_arrays(arrays) 4178 4179 while isinstance(arrays, (list, tuple)): -> 4180 result.append(tuple([shape(deepfirst(a))[dim] for a in arrays])) 4181 arrays = arrays[0] 4182 dim += 1

~/miniconda3/envs/dcpy/lib/python3.8/site-packages/dask/array/core.py in <listcomp>(.0) 4178 4179 while isinstance(arrays, (list, tuple)): -> 4180 result.append(tuple([shape(deepfirst(a))[dim] for a in arrays])) 4181 arrays = arrays[0] 4182 dim += 1

IndexError: tuple index out of range ```