# Overloading problem

**URL:** <https://numba.discourse.group/t/overloading-problem/1046>\
**Category:** Community Support\
**Created:** [December 1, 2021, 2:09pm UTC](https://numba.discourse.group/t/overloading-problem/1046 "2021-12-01T14:09:18Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![hgrecco](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/hgrecco/32/132_2.png) [@hgrecco](https://numba.discourse.group/u/hgrecco)\
**Post date:** [December 1, 2021, 2:09pm UTC](https://numba.discourse.group/t/overloading-problem/1046/1 "2021-12-01T14:09:18Z")

</div>

I was having a weird problem that I was able to simplify to this example:

```auto
import numba as nb
import numpy as np
from numpy import testing

@nb.njit
def in_range(arr, mn, mx):
    if mn is None and mx is None:
        return np.full(arr.shape, True)

    if mx is None:
        return mn <= arr

    if mn is None:
        return arr < mx

    return np.logical_and(mn <= arr, arr < mx)

print(nb.version_info)
arr = np.asarray((1, 4, 5, 8))

# 1
testing.assert_array_equal(in_range(arr, None, None),
                           np.asarray([True, True, True, True]))

# 2
testing.assert_array_equal(in_range(arr, 4, None),
                           np.asarray([False, True, True, True]))

# 3
testing.assert_array_equal(in_range(arr, None, 4),
                           np.asarray([True, False, False, False]))

# 4
testing.assert_array_equal(in_range(arr, 4, 7),
                           np.asarray([False, True, True, False]))

```

and I am getting:

```auto
No implementation of function Function(<built-in function le>) found for signature:
 
 >>> le(none, array(int64, 1d, C))

```

This example works fine if I comment `@nb.njit`. It seems that #3 is trying to reuse an implementation with the wrong types. I am using Numba 0.53

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<div class="post-metadata">

**Author:** ![gmarkall](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/gmarkall/32/42_2.png) [@gmarkall](https://numba.discourse.group/u/gmarkall)\
**Post date:** [December 9, 2021, 11:11pm UTC](https://numba.discourse.group/t/overloading-problem/1046/2 "2021-12-09T23:11:59Z")

</div>

I think you may be hitting a limitation of the branch pruner - I suspect the branch pruner doesn’t remove the `if mx is None` branch, which would be required for this to compile successfully. It may be that you would have to have separate implementations of the function (e.g. using `@overload` or `@generated_jit`) to avoid Numba attempting to compile code in “invalid” branches.

@stuartarchibald or @sklam may have some more insight here.

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<div class="post-metadata">

**Author:** ![esc](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/esc/32/49_2.png) [@esc](https://numba.discourse.group/u/esc)\
**Post date:** [December 13, 2021, 2:25pm UTC](https://numba.discourse.group/t/overloading-problem/1046/3 "2021-12-13T14:25:59Z")

</div>

This is a bit of a roundabout way at getting what you want, but it does work. In this case I used `overload` to create an implementation of `in_range` that dispatches based on type and has four different implementation depending on the types of the arguments. This can probably be cleaned and shortened a bit, but I will post it anyway as step in the right direction.

```auto
import numba as nb
import numpy as np
from numpy import testing
from numba.extending import overload

def njit_in_range(arr, mn, mx):
    pass

@overload(njit_in_range)
def ol_in_range(arr, mn, mx):
    if isinstance(mn, nb.types.NoneType) and isinstance(mx, nb.types.NoneType):
        def imp(arr, mn, mx):
            return np.full(arr.shape, True)

    elif isinstance(mx, nb.types.NoneType):
        def imp(arr, mn, mx):
            return mn <= arr

    elif isinstance(mn, nb.types.NoneType):
        def imp(arr, mn, mx):
            return arr < mx

    else:
        def imp(arr, mn, mx):
            return np.logical_and(mn <= arr, arr < mx)

    return imp

@nb.njit
def in_range(arr, mn, mx):
    return njit_in_range(arr, mn, mx)

print(nb.version_info)
arr = np.asarray((1, 4, 5, 8))

testing.assert_array_equal(in_range(arr, None, None),
                           np.asarray([True, True, True, True]))

testing.assert_array_equal(in_range(arr, 4, None),
                           np.asarray([False, True, True, True]))

testing.assert_array_equal(in_range(arr, None, 4),
                           np.asarray([True, False, False, False]))

testing.assert_array_equal(in_range(arr, 4, 7),
                           np.asarray([False, True, True, False]))

```

Hope it helps!

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<div class="post-metadata">

**Author:** ![esc](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/esc/32/49_2.png) [@esc](https://numba.discourse.group/u/esc)\
**Post date:** [December 13, 2021, 2:27pm UTC](https://numba.discourse.group/t/overloading-problem/1046/4 "2021-12-13T14:27:38Z")

</div>

Note: I used the instructions here: [A guide to using @overload — Numba 0.52.0.dev0+274.g626b40e-py3.7-linux-x86\_64.egg documentation](https://numba.pydata.org/numba-doc/dev/extending/overloading-guide.html)

---

<div class="post-metadata">

**Author:** ![hgrecco](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/hgrecco/32/132_2.png) [@hgrecco](https://numba.discourse.group/u/hgrecco)\
**Post date:** [December 27, 2021, 4:48pm UTC](https://numba.discourse.group/t/overloading-problem/1046/5 "2021-12-27T16:48:43Z")

</div>

Thanks for the suggestion, this solves the problem!

---

<div class="post-metadata">

**Author:** ![esc](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/esc/32/49_2.png) [@esc](https://numba.discourse.group/u/esc)\
**Post date:** [January 20, 2022, 10:22am UTC](https://numba.discourse.group/t/overloading-problem/1046/6 "2022-01-20T10:22:03Z")

</div>

Great, happy it worked out!