I’m trying to apply a function over all pixels of an image (in my specific case I want to do some colour approximation per pixel, but I don’t think this is relevant for the problem) in an efficient way. The thing is that I’ve found different approaches to do so, but all of them apply a funct…
Tag: numpy
Insert a matrix in matplolib
I want to import a numpy matrix in a matplotlib plot. Let’s say that I have this matrix: In a scale from 0 to 3 of the x axis, I want to plot the points This is the code I use: and this is the outcome: Yet, if I have to use a large array of let’s say (1000×1000) elements
What am I doing wrong to calculate V from numpy array? I can not get array with “V” values
#ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() Answer The issues are the following: You are comparing an array instead of a value in a condition, which is ambiguous. Try 0 < value < a instead 0 < x < a To give an example of what you are doi…
positive weights and negative weights [closed]
Closed. This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago. Improve this question I have an array named as weights – I am trying for hours to get an a…
How to convert a pandas dataframe column to an image array i.e. a numpy array with shape (n,n) in Python?
Suppose my dataframe has 750 rows in a column and I want to convert that column to an image array of (20,20) numpy array. How to do that? EDIT1: I want to use the array for ax.contourf (x,y,z) as z. I got x,y by doing x,y=np.meshgrid(df3.x,df.y) now I want to convert another column to an (n,n) array to vary t…
How to change inf values in numpy array for the previous non inf value?
I have a numpy array that may contain inf values. The numpy array is a 1D vector of numbers. Is there a way to change the inf values of the array for the previous value of the array (which is not inf)? So if the 1000th index of the array is an inf it should replace it by the 999th
Which numpy index is copy and which is view?
Question Regarding Numpy Indexing which can either return copy or view, please confirm if my understandings are correct. If not, please provide explanations and provide pointers to the related specifications. Q: Basic slicing The Numpy Indexing documentation has Basic Slicing and Indexing section. I believe t…
How am I going wrong in glMultiDrawArraysIndirect function?
I’m programming using Python and Modern OpenGL, and I tried to implement the glMultiDrawArraysIndirect function in my code to draw a simple shape, I want to apply it later on to a more complex thing, but this is just a simple test that I don’t know exactly where the error is. In the VBO there is a…
How to get the last index of model’s prediction?
I am new to PyTorch. I have a variable pred which has a list of a tensor. So I wanted to access the last element which is the class. I did that by first converting the list into a tensor. Now, how do I access the last element or is there any better/efficient way of doing this? EDIT: For further
How to use np.unique on big arrays?
I work with geospatial images in tif format. Thanks to the rasterio lib I can exploit these images as numpy arrays of dimension (nb_bands, x, y). Here I manipulate an image that contains patches of unique values that I would like to count. (they were generated with the scipy.ndimage.label function). My idea w…