Develop Reference

Sympy not able to calculate minimum of a cubic root with an interval set

So I was working on a project and I came across this error related to sympy:
Traceback (most recent call last):
File "c:\Users\Andres\OneDrive - Centre d'Estudis Monlau\z.ottro\final program try 1\testing area 2.py", line 4, in <module>
Ymin = minimum(root(x,3), x, domain=Interval(-7,7))
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\calculus\util.py", line 837, in minimum
return function_range(f, symbol, domain).inf
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\calculus\util.py", line 220, in function_range range_int += Interval(vals.inf, vals.sup, left_open, right_open)
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\sets\sets.py", line 274, in inf
return self._inf
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\sets\sets.py", line 1910, in _inf
return Min(*self)
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\functions\elementary\miscellaneous.py", line 391, in __new__
args = frozenset(cls._new_args_filter(args))
File "C:\Users\Andres\AppData\Local\Programs\Python\Python39\lib\site-packages\sympy\functions\elementary\miscellaneous.py", line 564, in _new_args_filter
raise ValueError("The argument '%s' is not comparable." % arg)
ValueError: The argument '(-7)**(1/3)' is not comparable.
I was able to isolate where happened and recreate the error with these lines:
from sympy import *
x = Symbol("x")
Ymin = minimum(root(x,3), x, domain=Interval(-7,7))
I'm not undrestanding why it's happening, as when is root(x,2) it doasn't have this problem. Does anyone have a clue?

Okey i found an answer online posted by user6655984(stackoverflow) and i wanted to share it online:
expression = root(Abs(x), 3)*sign(x)

IndexError: list index out of range-QGIS

I Try to make plugin in qgis and I have a problem. Below is my code:
destination_layer = QgsProject.instance().mapLayersByName('Destination')[0]
matrix = QgsProject.instance().mapLayersByName('join')[0]
for f in matrix.getFeatures():
origin_expr = QgsExpression('Site Name={}'.format(f['Site Name']))
destination_expr = QgsExpression('Site Name={}'.format(f['Site Name_2']))
origin_feature = origin_layer.getFeatures(QgsFeatureRequest(origin_expr))
origin_coords = [(f.geometry().asPoint().x(), f.geometry().asPoint().y())
for f in origin_feature]
destination_feature = destination_layer.getFeatures(QgsFeatureRequest(destination_expr))
destination_coords = [(f.geometry().asPoint().x(), f.geometry().asPoint().y())
for f in destination_feature]
params = {
'INPUT':'NCR Road',
'START_POINT':'{},{}'.format(origin_coords[0][0], origin_coords[0][1]),
'END_POINT':'{},{}'.format(destination_coords[0][0], destination_coords[0][1]),
'STRATEGY':0,
'ENTRY_COST_CALCULATION_METHOD':0,
'DIRECTION_FIELD':'',
'VALUE_FORWARD':'',
'VALUE_BACKWARD':'',
'VALUE_BOTH':'',
'DEFAULT_DIRECTION':2,
'SPEED_FIELD':'',
'DEFAULT_SPEED':50,
'TOLERANCE':0,
'OUTPUT': 'Shortest Path Layer' }
print('Executing analysis')
processing.runAndLoadResults("qneat3:shortestpathpointtopoint", params)
Then when I run my code, it show this error:
Traceback (most recent call last):
File "C:\PROGRA~1\QGIS32~1.0\apps\Python39\lib\code.py", line 90, in runcode
exec(code, self.locals)
File "<input>", line 1, in <module>
File "<string>", line 16, in <module>
IndexError: list index out of range
Why it is not working in plugin?

We need more information like which code is on line 90? Anyway I would double check and making sure your index is doing correct things
'START_POINT':'{},{}'.format(origin_coords[0][0], origin_coords[0][1]),
'END_POINT':'{},{}'.format(destination_coords[0][0], destination_coords[0][1]),
And
destination_layer = QgsProject.instance().mapLayersByName('Destination')[0]
matrix = QgsProject.instance().mapLayersByName('join')[0]

Curses addstr() variable instead of integer causes error?

I've started working on a curses program in python and I have come across this issue. The code "logo.addstr(count, 1, line)" gives this error:
Traceback (most recent call last):
File "intro.py", line 90, in <module>
curses.wrapper(main)
File "/usr/lib/python3.7/curses/__init__.py", line 102, in wrapper
return func(stdscr, *args, **kwds)
File "intro.py", line 22, in main
show_rank_logo()
File "intro.py", line 87, in show_rank_logo
logo.addstr(count, 1, line)
_curses.error: addwstr() returned ERR
If you replace "count" with 1, the lines will show up but on one line (as it should). This file is ASCII art so I want it to display in the window (named logo) all at once. This is why I added a count to the loop. But the variable which equals 1 somehow gives an error.
def show_rank_logo():
logo = curses.newwin(35, 105, 1, 51)
logo.box()
count = 1
with open('platinum_logo.txt') as file:
for line in file.readlines():
logo.addstr(count, 1, line)
count += 1
logo.refresh()
Looking for any help!

Python, PIL and libtiff issue

When I do general PIL commands in Python, I get such an error message:
>>> im.save('layer_86_.tiff')
TIFFSetField: layer_86_.tiff: Unknown tag 33922.
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python34\lib\site-packages\PIL\Image.py", line 1685, in save
save_handler(self, fp, filename)
File "C:\Python34\lib\site-packages\PIL\TiffImagePlugin.py", line 1185, in _save
e = Image._getencoder(im.mode, 'libtiff', a, im.encoderconfig)
File "C:\Python34\lib\site-packages\PIL\Image.py", line 430, in _getencoder
return encoder(mode, *args + extra)
RuntimeError: Error setting from dictionary
I've seen at Github and SO similar questions, that date back to many years ago. But in my case this problem still can be reproduced. I've even installed libtiff.dll and put it in the System32 and SysWOW64 folders, but to no avail. So, how can I fix it?
This is another error message, that I see, when I try to rotate an image:
>>> from PIL import Image
>>> Image.MAX_IMAGE_PIXELS = 100000000000
>>> img = Image.open('layer_71_.tiff')
>>> img.rotate(80,expand=True)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python34\lib\site-packages\PIL\Image.py", line 1603, in rotate
return self.transform((w, h), AFFINE, matrix, resample)
File "C:\Python34\lib\site-packages\PIL\Image.py", line 1862, in transform
im.__transformer((0, 0)+size, self, method, data, resample, fill)
File "C:\Python34\lib\site-packages\PIL\Image.py", line 1910, in __transformer
image.load()
File "C:\Python34\lib\site-packages\PIL\ImageFile.py", line 245, in load
if not self.map and (not LOAD_TRUNCATED_IMAGES or t == 0) and e < 0:
TypeError: unorderable types: tuple() < int()
So it seems like PIL does not work in many cases.

Can I use a field called size in a MongoEngine document?

I have a document:
class Hamburger(Document):
size = IntField(default=0, required=True)
which I can use fine
h = Hamburger()
h.size = 5
h.save()
until I try an update_one for example
Hamburger.objects().update_one(set__size=5)
which throws this exception:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/site-packages/mongoengine/queryset/base.py", line 467, in update_one
upsert=upsert, multi=False, write_concern=write_concern, **update)
File "/usr/local/lib/python2.7/site-packages/mongoengine/queryset/base.py", line 430, in update
update = transform.update(queryset._document, **update)
File "/usr/local/lib/python2.7/site-packages/mongoengine/queryset/transform.py", line 207, in update
field = cleaned_fields[-1]
IndexError: list index out of range
It is possible to have a Document with a field called size? Is there any way to achieve this?