# Help with error message

**URL:** <https://numba.discourse.group/t/help-with-error-message/304>\
**Category:** Support: What is this error message?\
**Created:** [October 21, 2020, 7:09pm UTC](https://numba.discourse.group/t/help-with-error-message/304 "2020-10-21T19:09:06Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![jrjames83](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@jrjames83](https://numba.discourse.group/u/jrjames83)\
**Post date:** [October 21, 2020, 7:09pm UTC](https://numba.discourse.group/t/help-with-error-message/304/1 "2020-10-21T19:09:06Z")

</div>

Just discovered this discourse group.

Figured I would cross-post my SO question which contains the code and stack trace. [https://stackoverflow.com/questions/64469950/numba-numpy-understanding-error-message](https://stackoverflow.com/questions/64469950/numba-numpy-understanding-error-message)

A little more context:  
My dataset is a pandas dataframe with a single column. That column is an array of values, having some irregular length. I need to run union commands for all elements, as shown in the example code. I’m going to pass in the .values attribute of that column into my process\_values function.

a) is this a good use case for numba? I’m trying to improve on pandas .apply method.  
b) can you help be decrypt the error message?

Thanks so much,

Jeff

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**Author:** ![luk-f-a](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/luk-f-a/32/56_2.png) [@luk-f-a](https://numba.discourse.group/u/luk-f-a)\
**Post date:** [October 21, 2020, 8:51pm UTC](https://numba.discourse.group/t/help-with-error-message/304/2 "2020-10-21T20:51:11Z")

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hi @jrjames83, I have replied on SO. Let me know if it’s clear how to solve it using lists.

Luk

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<div class="post-metadata">

**Author:** ![jrjames83](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@jrjames83](https://numba.discourse.group/u/jrjames83)\
**Post date:** [October 21, 2020, 8:52pm UTC](https://numba.discourse.group/t/help-with-error-message/304/3 "2020-10-21T20:52:47Z")

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Nice! Taking a look @luk-f-a. Appreciate the quick reply.

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<div class="post-metadata">

**Author:** ![jrjames83](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@jrjames83](https://numba.discourse.group/u/jrjames83)\
**Post date:** [October 21, 2020, 9:08pm UTC](https://numba.discourse.group/t/help-with-error-message/304/4 "2020-10-21T21:08:12Z")

</div>

```python
from numba import jit
from numba.typed import List

indices = np.arange(8806806, dtype=np.int64)
sizes = np.ones(8806806, dtype=np.int64)
connected_components = 8806806

@jit(npython=True)
def root(p: int) -> int:
    while p != indices[p]:
        indices[p] = indices[indices[p]]
        p = indices[p]
    return p

@jit(npython=True)
def connected( p: int, q: int) -> bool: 
    return root(p) == root(q)

@jit(npython=True)
def union( p: int, q: int) -> None:
    root1 = root(p)
    root2 = root(q)
    if root1 == root2:
        return

    if (sizes[root1] < sizes[root2]):
        indices[root1] = root2
        sizes[root2] += sizes[root1]
    else:
        indices[root2] = root1
        sizes[root1] += sizes[root2]

    connected_components -= 1
    
@jit(nopython=True)
def process_values(arr):
    for row in arr:
        for first, second in zip(arr, arr[1:]):
            union(first, second)
            
          

mylist = List()
for x in [[8018361, 4645960], [8018361, 4645960]]:
    new_list = List()
    new_list.extend(x)
    mylist.append(new_list)

process_values(mylist)

```

`mylist` evidently gets created, but now:

```auto
---------------------------------------------------------------------------
TypingError Traceback (most recent call last)
<ipython-input-64-6e08ff92ded5> in <module>
     48 
     49 
---> 50 process_values(mylist)
     51 
     52 

/opt/conda/lib/python3.7/site-packages/numba/core/dispatcher.py in _compile_for_args(self, *args, **kws)
    399 e.patch_message(msg)
    400 
--> 401 error_rewrite(e, 'typing')
    402 except errors.UnsupportedError as e:
    403 # Something unsupported is present in the user code, add help info

/opt/conda/lib/python3.7/site-packages/numba/core/dispatcher.py in error_rewrite(e, issue_type)
    342 raise e
    343 else:
--> 344 reraise(type(e), e, None)
    345 
    346 argtypes = []

/opt/conda/lib/python3.7/site-packages/numba/core/utils.py in reraise(tp, value, tb)
     78 value = tp()
     79 if value. __traceback__ is not tb:
---> 80 raise value.with_traceback(tb)
     81 raise value
     82 

TypingError: Failed in nopython mode pipeline (step: nopython frontend)
Internal error at <numba.core.typeinfer.CallConstraint object at 0x7f2127283ed0>.
"<class 'numba.core.cpu.CPUTargetOptions'> does not support option: 'npython'"
[1] During: resolving callee type: type(CPUDispatcher(<function union at 0x7f21272b2320>))
[2] During: typing of call at <ipython-input-64-6e08ff92ded5> (39)

Enable logging at debug level for details.

File "<ipython-input-64-6e08ff92ded5>", line 39:
def process_values(arr):
    <source elided>
        for first, second in zip(arr, arr[1:]):
            union(first, second)
            ^

```

What are the patterns then for getting my original array of arrays into this typed list format?

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<div class="post-metadata">

**Author:** ![luk-f-a](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/luk-f-a/32/56_2.png) [@luk-f-a](https://numba.discourse.group/u/luk-f-a)\
**Post date:** [October 22, 2020, 7:45am UTC](https://numba.discourse.group/t/help-with-error-message/304/5 "2020-10-22T07:45:53Z")

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you just had a typo, `@jit(npython=True)` should be `@jit(nopython=True)`

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<div class="post-metadata">

**Author:** ![jrjames83](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@jrjames83](https://numba.discourse.group/u/jrjames83)\
**Post date:** [October 23, 2020, 8:12pm UTC](https://numba.discourse.group/t/help-with-error-message/304/6 "2020-10-23T20:12:56Z")

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Thanks @luk-f-a - good catch. I’ll report back with any updates and what the code ends up looking like.

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<div class="post-metadata">

**Author:** ![ehsantn](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/ehsantn/32/258_2.png) [@ehsantn](https://numba.discourse.group/u/ehsantn)\
**Post date:** [March 12, 2021, 8:53pm UTC](https://numba.discourse.group/t/help-with-error-message/304/7 "2021-03-12T20:53:59Z")

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@jrjames83 [Bodo](https://numba.discourse.group/t/introducing-bodo-community-edition-for-pandas-acceleration/604) supports accelerating Pandas apply functions directly (usually great speedups). For example, you can just pass a Series with array of array input to Bodo:

```
import numpy as np
import pandas as pd
import bodo

    
@bodo.jit
def process_values(arr):
    print(arr)

process_values(
    pd.Series(
        [np.array([8018361, 4645960]),
            np.array([1137555, 7763897]),
            np.array([7532943, 2248813]),
            np.array([5352737, 71466, 3590473, 5352738, 2712260])], dtype='object')) 

```

Could you post your original Pandas code with apply so I can suggest how to use Bodo?