Questions tagged [numpy-ndarray]
Numpy Ndarray refers to the N-dimensional array type that describes the collection of the same type in the Python library NumPy. Use this tag for questions related to this array type.
numpy-ndarray
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Storing numpy arrays in PostgreSQL: BYTEA vs. ARRAY for large integer arrays
I'm aware that PostgreSQL supports storing arrays directly. Is it more effective to store large numpy arrays of integers using PostgreSQL's native ARRAY type compared to BYTEA? Specifically, my arrays ...
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Why reshape is needed for Sequential models after minmaxscaler class? and how to use?
My recent project is based on 'Stock Prediciton" I'm working on df["Open"] as nd.array.
Trying to understand intuitively how this works and whether my predicted data will be correct or ...
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ndarray a obtained from b.diagonal() has its value changed after the b modification
I'm a bit confused by the behavior of the below code and wondering if someone could shed some light on this. Basically, I have a matrix called mat which is a numpy ndarray. I get its diagonal using ...
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Place pixels on a grid [closed]
I have a two dimensional numpy array: myarray=[[0,0],[1,1],[2,2]]
I also have a grid of points: mygrid=[[70,70],[100,100],[30,30]]
I want to efficiently create a new array which contains points of ...
- 143
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Extracting the values of Fipy diffusion and convection terms
I am new to Fipy and I was wondering if there is a way how to extract the values of a diffusion or convections terms. in the case of a cell variable this is easy but diffusion or convections are in ...
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Conditionally changing elements of a numpy array using for loop
I have a two dimensional numpy array, and I'm wanting to change all of the 'male' values to 0 and all of the 'female' values to 1.
If I try to assign arr2D[row,element] to a specific value,
I get an ...
4
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2
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Optimal multiplication of two 3D arrays having a variable dimension
I would like to multiply tensors R = {R_1, R_2, ..., R_M} and X = {X_1, X_2, ..., X_M} where R_i and X_i are 3×3 and 3×N_i matrices, respectively. How can I make maximum use of NumPy functionalities ...
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Numba njit making function call involving long expressions extremely slow
I am writing a finite volume code to solve the inviscid, compressible Euler equations. As a part of this, I am performing what is known as the Cauchy-Kovalevskaya process. A code snippet is given ...
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Numpy array slicing with a comma
There are multiple questions on StackOverflow, asking how the comma syntax works, but most of them refer to m[:,n] which refers to the nth column. Similarly, m[n,:] refers to the nth row. I find this ...
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np.ones(30011,30011) needs 7.2GB, but Task Manager shows 5.3GB
A 30,011x30,011 of 64-bit floats takes 7.2GB. There are many explanations for why one might see np.zeros([30011,30011]) take up (say) a miniscule 0.7MB. However, my Windows 2010 Task Manager also ...
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Simplest equivalent implementation of numpy.ma.notmasked_edges() for use in JAX
I have a square numpy.ndarray and a numpy boolean mask of the same shape. I want to find the first element in each row of the array that is not masked.
My code currently relies on numpy.ma....
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NumPy array size and performance differences for int8 vs bool dtype
I am trying to use numpy's nbytes attribute to examine the memory usage of arrays with different dtype. I noticed the following:
>>> np.zeros(1024, dtype='int64').nbytes / 1024 # in kB
8.0
...
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TypeError: unhashable type: 'numpy.ndarray' in array to set
in this def i get TypeError: unhashable type: 'numpy.ndarray' in line retrieved_indices_set = set(retrieved_indices)
def evaluate_retrieval(query_idx, retrieved_indices, relevant_indices):
# ...
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Why is numpy shuffle not working in a loop?
Thanks very much in advance.
I have a numpy array called X_test
X_test.shape
(11829, 16, 9)
I am trying to shuffle the 2nd column of each element of the array with the code below. However, X_test_s ...
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CFS thredds data don't work in xarray lib
I need to get u,v at 10 meters from CFS thredds from the historic forecast, but, when I open and try to get the variables, the error: FunctionalityNotEnabledError: Functionality not enabled pops.
My ...
