35,387 questions
Best practices
0
votes
0
replies
12
views
Advise of best practices for updating and deleting vectors in a large PolarDB table?
My application requires that vector embeddings are frequently updated or deleted. For example, when a user edits a blog post, its corresponding text embedding needs to be re-calculated and updated in ...
- 471
0
votes
0
answers
34
views
PolarDB vector database data import
I tried to import some MD files into PolarDB vector database. Some files hit errors like follow:
Failed file: monthly_2021_07_05.md
Log file: import_with_errors.log
Error context:
2025-10-28 17:23:07,...
- 21
0
votes
1
answer
76
views
Performing product operation on consecutive true segments in a vector
I have two vectors of equal length, one integer vector and one boolean vector. I want to calculate the product of elements in the integer vector where the corresponding boolean vector has consecutive ...
- 3
5
votes
0
answers
209
views
Why is my user-defined contiguous 2D array not dramatically faster than std::vector<std::vector<>>?
I implemented a simple 2D array wrapper using a single contiguous std::vector and, benchmarked it against std::vector<std::vector<>>.
Surprisingly, array2d is just slightly faster!
#...
- 151
0
votes
1
answer
108
views
How to remove duplicate rows based on array column subset relationship?
I have a DolphinDB table with an array vector column. I need to remove duplicate rows based on subset relationships within that column.
Sample Input:
sym
prices
a
[3,4,5,6]
a
[3,4,5]
a
[2,4,5,6]
a
[5,...
- 33
-1
votes
1
answer
113
views
Integer or Double vector? [duplicate]
print(krit)
names weight
1 may 36
2 mayer 49
3 mayo 35
4 mali 50
> mean(krit$weight)
[1] 42.5
> typeof(weight)
[1] "double"
> typeof(names)
[1] "character&...
0
votes
1
answer
45
views
Multiple CDFS on the same plot with specified ranges
I was trying to do something for a project where I create two random 3D vectors, project them onto a 2D plane by removing their x-component, taking the dot product between the two to find their ...
- 1
Advice
0
votes
3
replies
114
views
How to adjust vector length in quiver plot?
This is the program I am using:
fig, ax = plt.subplots(figsize=(4, 4))
t, dt = np.linspace(-4, 4, 10, retstep=True)
x = t
y = t**3 - 9*t
xy = np.stack((x, y), axis=1)
n = len(xy)
d1ydx1 = np....
- 1,226
Best practices
0
votes
3
replies
90
views
How to plot unit tangent and unit normal vectors on a parameterized curve?
I am working to practice on some simple parameterized curve given by:
import numpy as np
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(6, 3))
t = np.linspace(-4, 4, 100)
x = t
y = ...
- 1,226
0
votes
1
answer
47
views
Why does the use of "enlist" in the cross-sectional engine sometimes result in errors and sometimes work normally?
I am using the cross-sectional engine and need to store multiple rows of fields as a single array vector. However, I have encountered several issues during the process:
The scenarios I attempted are ...
- 21
-8
votes
2
answers
234
views
My code fails to compile with "no match for 'operator=='" error [closed]
I tried using the std::getline() function with a vector, and I want to make something that turns the following user input:
3
AA AA
BB BB
CC CC
into the following output:
AA AA, BB BB, and CC CC [...
0
votes
1
answer
128
views
Trouble cycling through values in a for loop and filling a list in R
I'm trying to estimate the population growth of a population with different growths rates, shown below
r <-c(0.5, 1.0, 1.5, 2, 2.5, 2.6, 2.7, 2.8, 2.9)
I'm trying to fill N_List with the ...
0
votes
1
answer
43
views
How to reshape vector by duplicating each element twice?
I'm working with DolphinDB V3.00.3 and need to transform a vector by duplicating each element consecutively, while keeping the original order and final vector length the same as the input.
Example
...
0
votes
0
answers
30
views
ECU Extract Import in Comasso BSWDT Tool
I have to import ecu extract ARXML file into the COMASSO toolchain. I find the option in file->import->BCT->EcuExtract.
when I try to import ecu extract then tool requires .oaw and .ext files ...
1
vote
1
answer
65
views
Any memory safety concerns when using Haskell's vector unsafeFreeze / unsafeThaw on unpinned vector?
Apart from the known safety concerns documented for unsafeFreeze / unsafeThaw, is there any issue using these functions with non-pinned backing data (that is, as I understand everything except Vector....
- 9,458