Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions #129

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36 changes: 29 additions & 7 deletions arraycontext/container/traversal.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

or any other such traversal.
"""
def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
if type(_ary) is leaf_class:
return map_func(_ary)
else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
except NotAnArrayContainerError:
return map_func(_ary)
else:
return reduce_func([
rec(subary) for _, subary in iterable
])
subary_results = [
rec(subary) for _, subary in iterable]
filtered_subary_results = [
result for result in subary_results
if result is not None]
if len(filtered_subary_results) > 0:
return reduce_func(filtered_subary_results)
else:
return None

return rec(ary)
result = rec(ary)

if result is None:
raise ValueError("cannot reduce empty array container")
Comment on lines +488 to +489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.

@majosmmajosmDec 27, 2021

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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?

The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?

@alexfiklalexfiklDec 27, 2021

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For reference, calling np.max on an empty list raises

>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.

@inducerinducerDec 28, 2021

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The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.

That's a great point. I had not thought far enough to realize that, but I agree now.

Should that maybe be fixed instead?

I think that's exactly what we should do.

We should probably do something like that in actx.np too.

I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.

One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.

@inducerinducerDec 28, 2021

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Did some work towards that:

That latter PR needs some more work done to it. @majosm, could you take a look?


return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
# NOTE: this wrapper matches the signature of `deserialize_container`
# to make plugging into `_multimap_array_container_impl` easier
def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
return reduce_func([subary for _, subary in iterable])
filtered_subary_results = [
result for _, result in iterable
if result is not None]
if len(filtered_subary_results) > 0:
return reduce_func(filtered_subary_results)
else:
return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
map_func, *args,
reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

if result is None:
raise ValueError("cannot reduce empty array container")
Comment on lines +529 to +530

@inducerinducerDec 27, 2021

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As above.


return result

# }}}


Expand Down
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

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The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

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Owner
Choose a reason for hiding this comment

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Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
#129
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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CollaboratorAuthor
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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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Collaborator
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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
#129
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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CollaboratorAuthor
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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

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The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

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Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Owner
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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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CollaboratorAuthor
Choose a reason for hiding this comment

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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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Collaborator
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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

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Copy Markdown

Owner
Choose a reason for hiding this comment

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The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

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Owner
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Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
#129
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Owner
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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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Copy Markdown

CollaboratorAuthor
Choose a reason for hiding this comment

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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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Collaborator
Choose a reason for hiding this comment

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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

Copy link


Copy Markdown

Owner
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Allow empty sub-containers in reductions#129

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Allow empty sub-containers in reductions
#129
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36 changes: 29 additions & 7 deletions
arraycontext/container/traversal.py

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -464,7 +464,7 @@ def rec_map_reduce_array_container(

 or any other such traversal.
 """
 def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 def rec(_ary: ArrayOrContainerT) -> Optional[ArrayOrContainerT]:
 if type(_ary) is leaf_class:
 return map_func(_ary)
 else:
Expand All@@ -473,11 +473,22 @@ def rec(_ary: ArrayOrContainerT) -> ArrayOrContainerT:
 except NotAnArrayContainerError:
 return map_func(_ary)
 else:
 return reduce_func([
 rec(subary) for _, subary in iterable
 ])
 subary_results = [
 rec(subary) for _, subary in iterable]
 filtered_subary_results = [
 result for result in subary_results
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

 return rec(ary)
 result = rec(ary)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+488
 to 
+489

@inducerinducerDec 27, 2021

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Personally, I think reducing over an empty container is well-defined: just return the neutral element. reduce_func should be trusted to do the right thing. What was the reasoning for putting in this error message? Basically, what I'm pushing for is to get rid of it and return reduce_func([]) instead.
@majosmmajosmDec 27, 2021

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CollaboratorAuthor
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If reduce_func worked for an empty list, I think this PR wouldn't be needed, right?
The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs. Should that maybe be fixed instead?
@alexfiklalexfiklDec 27, 2021

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Collaborator
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For reference, calling np.max on an empty list raises
>>> np.max([])
ValueError: zero-size array to reduction operation maximum which has no identity

and requires specifying an initial value with np.max([], initial=np.inf). We should probably do something like that in actx.np too.
@inducerinducerDec 28, 2021

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Owner
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The motivation for this was for things like actx.np.max where reduce_func doesn't (currently) behave nicely for empty inputs.
That's a great point. I had not thought far enough to realize that, but I agree now.
Should that maybe be fixed instead?
I think that's exactly what we should do.
We should probably do something like that in actx.np too.
I agree. While I wasn't loving numpy's interface of "no implicit neutral" element at first, I think it makes sense from the perspective of integers. I think we should aim to replicate this, both at the level of actx.np, and for the array container reductions under discussion here.
One subtlety is the ValueError for empty arrays. For symbolically-shaped pytato arrays, it may not be possible to do a perfect job.
@inducerinducerDec 28, 2021

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Did some work towards that:
That latter PR needs some more work done to it. @majosm, could you take a look?

 return result


def rec_multimap_reduce_array_container(
Expand All@@ -503,12 +514,23 @@ def rec_multimap_reduce_array_container(
 # NOTE: this wrapper matches the signature of `deserialize_container`
 # to make plugging into `_multimap_array_container_impl` easier
 def _reduce_wrapper(ary: ContainerT, iterable: Iterable[Tuple[Any, Any]]) -> Any:
 return reduce_func([subary for _, subary in iterable])
 filtered_subary_results = [
 result for _, result in iterable
 if result is not None]
 if len(filtered_subary_results) > 0:
 return reduce_func(filtered_subary_results)
 else:
 return None

return _multimap_array_container_impl(
result = _multimap_array_container_impl(
 map_func, *args,
 reduce_func=_reduce_wrapper, leaf_cls=leaf_class, recursive=True)

 if result is None:
 raise ValueError("cannot reduce empty array container")

Comment on lines

+529
 to 
+530

@inducerinducerDec 27, 2021

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As above.

 return result

# }}}


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