centroids | Centroids as a Service
kandi X-RAY | centroids Summary
kandi X-RAY | centroids Summary
This application reads a valid geojson FeatureCollection and returns a valid geojson FeatureColleciton of centroids.
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Top functions reviewed by kandi - BETA
- Generate a list of centroids
- Get the centroids of a polygon
- Check if a file is allowed
- List of centroids
centroids Key Features
centroids Examples and Code Snippets
Community Discussions
Trending Discussions on centroids
QUESTION
I am trying to learn the k-means clustering algorithm in MATLAB without using inbuilt k-means function. Say I have the data of size 1x100 and I want to group them into two clusters. So how can I do this. I want to visualize the two centroids and data together on a plot in MATLAB. Note : When I plot in MATLAB, I am able to see only data but not the data and two centroids simultaneously.
Any help in this regard is highly appreciated.
...ANSWER
Answered 2021-Jun-08 at 09:03A minimal K-means clustering algorithm in matlab could be:
QUESTION
I am using spgwr::ggwr()
to fit generalized geographically weighted regression with Poisson model and log-link function. The results provide local coefficient estimates, but i am missing how to get their standard errors (or t statistics) to compute pseudo p-values.
Below is a toy example using SpatialEpi::NYleukemia
dataset:
ANSWER
Answered 2021-Jun-06 at 15:55You may obtain standard errors from local coefficients running the function GWmodel::ggwr.basic
. Function spgwr::ggwr()
returns coefficients but no standard errors.
QUESTION
I have a 4 column dataframe which I extracted from the iris dataset. I use kmeans to plot 3 clusters from all possible combinations of 2 columns.
However, there seems to be something wrong with the output, especially since the cluster centers are not placed at the center of the clusters. I have provided examples of the output. Only cluster_1 seems OK but the other 3 look completely wrong .
How best can I fix my clustering? This is the sample code I am using
...ANSWER
Answered 2021-May-31 at 23:51You compute the clusters in four dimensions. Note this implies the centroids are four-dimensional points too. Then you plot two-dimensional projections of the clusters. So when you plot the centroids, you have to pick out the same two dimensions that you just used for the scatterplot of the individual points.
QUESTION
in geopandas I use this code to create centroid parameter from geometric parameter.
...ANSWER
Answered 2021-May-25 at 12:43To get the representative points that always fall within their corresponding polygons can be done in geopandas
with the function called representative_point()
. Here is a demo code that creates and plots the polygons and their rep. points.
QUESTION
I have 2 data frames:
df1
...ANSWER
Answered 2021-May-14 at 04:01You will need to prepare the data in certain format to feed into plotly so plotly know which point is which, and which point should be connected by a line. Below is a way to achieve it.
QUESTION
From this book here
...ANSWER
Answered 2021-Mar-17 at 15:46Although RStudio told me, all packages were up to date, the problem continued to exist. The solution was a full update of R and all packages. The process on Windows:
- Run
installr::update()
from Rgui.exe (in \R\R-4.0.4\bin\x64). - Update Windows environment variable
R_LIBS
the the new \R\R-4.0.4\library. - update Rprofile.site in \R\R-4.0.4\etc and make sure there is only one
.libPaths()
. (There has to be a line.libPaths("C:/R/R-4.0.4/library")
or just add it.) - Check if there are pending package updates in RStudio
QUESTION
First off, sorry for the length of the post.
I'm working on a project to classify plants based on an image of the leaf. In order to reduce the variance of the data I need to rotate the image so the stem would be horizontally aligned at the bottom of the Image (at 270 degrees).
Where I am at so far...
What I have done so far is to create a thresholded image and from there find contours and draw an ellipse around the object (in many cases it fails to involve the whole object so the stem is left out...), after that, I create 4 regions (with the edges of the ellipse) and try to calculate the minimum value region, this is due to the assumption that at any of this points the stem must be found and thus it will be the less populated region (mostly because it will be surrounded by 0's), this is obviously not working as I would like to.
After that I calculate the angle to rotate in two different ways, the first one involves the atan2
function, this only requires the point I want to move from (the centre of mass of the least populated region) and where x=image width / 2
and y = height
. This method works in some cases, but in most cases, I don't get the desired angle, sometimes a negative angle is required and it yields a positive one, ending up with the stem at the top. In some other cases, it just fails in an awful manner.
My second approach is an attempt to calculate the angle based on 3 points: centre of the image, centre of mass of the least populated region and 270º point. Then using an arccos
function, and translating its result to degrees.
Both approaches are failing for me.
Questions
- Do you think this is a proper approach or I'm just making things more complicated than I should?
- How can I find the stem of the leaf (this is not optional, it must be the stem)? because my idea is not working so well...
- How can I determine the angle in a robust way? because of the same reason in the second question...
Here are some samples and the results I'm getting (the binary mask). The rectangles denote the regions I'm comparing, the red line across the ellipse is the major axis of the ellipse, the pink circle is the centre of mass inside the minimum region, the red circle denotes the 270º reference point (for the angle), and the white dot represents the centre of the image.
My current Solution
...ANSWER
Answered 2021-Apr-23 at 21:58Here's what I mean, and this needs to be refined. This draws an imaginary line through the image center every 5 pixels along the top edge, and then every 5 pixels along the left edge, adds up the pixel values on both sides of the line, and prints the min and max ratios. The fourth value of the tuple should be the angle of rotation.
QUESTION
I have a 2D grid of cells, like so:
I want to find the "centroids," or the places in each room that can see the most other cells. For example, "centroid" 1 can see 500 other cells, "centroid" 2 can see 400 other cells (NOT included in the first 500), and so on (if there's a better name for this let me know).
I'm currently doing this with the code below.
...ANSWER
Answered 2021-Apr-29 at 00:11For a big speedup (from quadratic in the number of rooms to linear), you could decide to check just a few integer slopes at each point. These are equivalence classes of visibility, i.e., if cell x can see cell y along such a line, and cell y can see cell z along the same line, then all 3 cells can see each other. Then you only need to compute each "visibility interval" along a particular line once, rather than per-cell.
You would probably want to check at least horizontal, vertical and both 45-degree diagonal slopes. For horizontal, start at cell (1, 1), and move right until you hit a wall, let's say at (5, 1). Then the cells (1, 1), (2, 1), (3, 1) and (4, 1) can all see each other along this slope, so although you started at (1, 1), there's no need to repeat the computation for the other 3 cells -- just add a copy of this list (or even a pointer to it, which is faster) to the visibility lists for all 4 cells. Keep heading right, and repeat the process as soon as you hit a non-wall. Then begin again on the next row.
Visibility checking for 45-degree diagonals is slightly harder, but not much, and checking for other slopes in which we advance 1 horizontally and some k vertically (or vice versa) is about the same. (Checking for for general slopes, like for every 2 steps right go up 3, is perhaps a bit trickier.)
Provided you use pointers rather than list copies, for a given slope, this approach spends amortised constant time per cell: Although finding the k horizontally-visible neighbours of some cell takes O(k) time, it means no further horizontal processing needs to be done for any of them. So if you check a constant number of slopes (e.g., the four I suggested), this is O(n) time overall to process n cells. In contrast, I think your current approach takes at least O(nq) time, where q is the average number of cells visible to a cell.
QUESTION
im really new for gpu coding i found this Kmeans cupy code my propouse is work with a large data base (n,3) for example to realize about the timing difference on gpu and cpu , i wanna have a huge number of clusters but i am getting a memory management error. Can someone give me the route I should take to research and fix it, i already research but i have not a clear start yet.
...ANSWER
Answered 2021-Apr-26 at 13:21Assuming that CuPy is clever enough not to create explicit copies of the broadcasted input of var_kernel
, the output distances
has to have a size of 2 * num * num_clusters
which are exactly the 6,400,000,000 Bytes it is trying to allocate. You could have a way smaller memory footprint by never actually writing the distances to memory which means fusing the var_kernel
with argmin
. See this part of the docs.
If I understand the example there correctly, this should work:
QUESTION
Until now, I've been handling translucency by sorting my translucent triangles back to front. This works very well for quads, but I'd like to incorporate translucency in my models now.
I've thought of separating the translucent tris out and sorting them in the same way as my quads. Sorting by their centroids, then streaming the results into an IBO for just them each frame. But the number of triangles in a model, and the need to transform them on the CPU according to a table of bones, and blend shapes, and some other things in my vertex shader... This doesn't seem like a good solution in performance or sanity.
My models are about 4K tris each, with maybe 20 in a scene at worst, and I'd really like to lean into a simple cute style that relies on translucency, which doesn't have to be physically accurate, or draw objects behind 4 or more layers of translucency.
What technique might work well for my situation, in 2021? I'm using OpenGL 3.3 but I'll use another version if new features exist for this.
...ANSWER
Answered 2021-Apr-20 at 12:34Afaik, there's no easy solution to what you want to do. However, there are some things that you can do:
- Don't sort triangles at all, and only sort individual draw calls. This is the easiest solution and is utilised by most games, if they use translucent/transparent objects in the first place. Of course, this might not have the best looks (though it works well with convex shapes), but it will have very good performance.
- Order-independet transparency: There are some pixel shader based techniques for rendering transparent/translucent objects without having to sort anything at all. These techniques usually are approximations (there are also some non-approximate algorithms) and tend work the best for things like smoke (where small errors aren't as noticable), or when not many transparent/translucent triangles overlap each other anyway.
- Compute Shaders: You can use a compute shader to transform your individual vertices according to your animation, and then use another compute shader to sort the triangles on the GPU. That is probably the most straight-forward improvement of what you'd otherwise do on the CPU, and there are many examples for sorting stuff on the GPU out there. But, if you've never worked with compute shaders before, it might be a bit hard to wrap your head around their strengths and limitations at first.
- Ray Tracing: This would probably be the most complex way to solve that problem, since you'll need specific hardware, generate corresponding data structures and a few new shaders, and on top of that, even with modern hardware, ray tracing is quite costly (though probably still faster than sorting triangles on the CPU each frame). But it also doesn't need your triangles to be sorted and will actually work perfectly well even if different translucent objects are intersecting/interleaving each other.
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Install centroids
You can use centroids like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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