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Thread: Fit straight line to pandas time series data with semilog plot
Post: RE: Fit straight line to pandas time series data w...
| For some reason the fit became more accurate when I changed x = np.arange(df.iloc[:,-1:].size) to x = np.linspace(0,1,len(df.iloc[:,-1:])). Grateful for an explanation if this really is the solution. |
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schniefen |
Homework |
2 |
1,531 |
Mar-06-2023, 07:24 PM |
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Thread: Fit straight line to pandas time series data with semilog plot
Post: Fit straight line to pandas time series data with ...
| I have sets of data, which look like this:
[attachment=2270]
I do the following:
df=pd.read_csv('data.csv')
timestamp_fields = ['Year', 'Month', 'Day', 'Hour', 'Minute','Second']
df['Date']=pd.to_d... |
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schniefen |
Homework |
2 |
1,531 |
Mar-06-2023, 05:16 PM |
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Thread: Plot time series data
Post: RE: Plot time series data
| (Mar-04-2023, 03:56 PM)noisefloor Wrote: Hi,
if you combine the first six columns to one column holding a datetime object, plotting should be easy.
Regards, noisefloor
Here is my current solution,... |
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schniefen |
Homework |
3 |
1,309 |
Mar-04-2023, 04:14 PM |
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Thread: Plot time series data
Post: Plot time series data
| I have a long list of data looking like this:
[attachment=2269]
Minute and Second are always zero since the data is the 1 hour average of a measurement, which is the last column. I would like to plo... |
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schniefen |
Homework |
3 |
1,309 |
Mar-04-2023, 02:17 PM |
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Thread: extract lower/upper antitriangular matrix
Post: extract lower/upper antitriangular matrix
| In numpy you can use np.tril(x) to extract the lower triangular matrix of an array x. However, I am interested in extracting the lower (upper) antitriangular matrix, that is, with zeros above (below) ... |
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schniefen |
Homework |
2 |
1,411 |
Dec-09-2022, 05:43 PM |
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Thread: rotate error function
Post: rotate error function
| I would like to rotate a function that is defined in terms of the error function, see here. I am unsure how to go about it, but I would like the resulting plot to be diagonal along the line y=-bx, whe... |
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schniefen |
Homework |
0 |
888 |
Dec-07-2022, 02:40 PM |
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Thread: animating 2d heat map
Post: animating 2d heat map
| Consider the following heat map:
from scipy import special
import numpy as np
import matplotlib.pyplot as plt
u0=200
r0x=25
r0y=25
rmax=2.5
alpha=2
t=0.575
y, x = np.meshgrid(np.linspace(0, 50, 100... |
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schniefen |
Homework |
0 |
1,341 |
Nov-20-2022, 10:00 PM |
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Thread: Simple animation -- time evolution of function
Post: Simple animation -- time evolution of function
| I would like to animate how a function evolves over time. I would like to do this using only plt.blablabla, not ax.blablabla. The function is defined as follows:
import numpy as np
from scipy import ... |
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schniefen |
Homework |
0 |
1,020 |
Nov-20-2022, 08:05 PM |
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Thread: Plotting periodic function with fft
Post: Plotting periodic function with fft
| I want to plot a T-periodic function using a restricted set of Fourier coefficients. The function equals sin(x/tau) for 0<=x<(2*pi*tau) and 0 for (2*pi*tau)<=x<T (it is periodically repeat... |
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schniefen |
Homework |
0 |
1,012 |
Nov-10-2022, 11:53 AM |
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Thread: 4D array with only elements on one side of the diagonal
Post: 4D array with only elements on one side of the dia...
| Given the parameters n and m, I'd like to initialize a n x n4D array where each entry is an m x m matrix, and where each column of the matrix is an array of type numpy.linspace(0,1,m). Furthermore, I'... |
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schniefen |
General Coding Help |
0 |
1,682 |
Dec-24-2020, 11:32 AM |
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Thread: Level curves don't match after rotation
Post: RE: Level curves don't match after rotation
| This has been solved. The curves do match, it is just that, when the function is rotated, its central axes changes, and in the square, it is longer than that of the non-rotated one. |
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schniefen |
General Coding Help |
1 |
1,531 |
Dec-14-2020, 09:56 PM |
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Thread: Level curves don't match after rotation
Post: Level curves don't match after rotation
| Consider the general 2D Gaussian function, centered at (0.5,0.5),
A*exp(-a*(-0.5 + x)**2-b*(-0.5 + x)*(-0.5 + y)-c*(-0.5 + y)**2)where the covariance matrix can be written in terms of the coefficient... |
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schniefen |
General Coding Help |
1 |
1,531 |
Dec-14-2020, 06:01 PM |
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Thread: Rotate 2D Gaussian given parameters
Post: RE: Rotate 2D Gaussian given parameters
| A rotation by 45 degrees, with the means (0.5,0.5) fixed, gives a’=(a-b+c)/2, b’=a-c=0 and c’=(a+b+c)/2 for a counterclockwise rotation and a’=(a+b+c)/2, b’=a-c=0 and c’=(a-b+c)/2 for a clockwise rota... |
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schniefen |
General Coding Help |
4 |
2,896 |
Dec-11-2020, 03:34 PM |
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Thread: Rotate 2D Gaussian given parameters
Post: RE: Rotate 2D Gaussian given parameters
| (Dec-10-2020, 06:44 PM)schniefen Wrote: (Dec-10-2020, 06:37 PM)ndc85430 Wrote: Can't you make use of a rotation matrix? For each point (x, y) the rotation matrix would give you new points (x', y')... |
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schniefen |
General Coding Help |
4 |
2,896 |
Dec-10-2020, 06:45 PM |
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Thread: Rotate 2D Gaussian given parameters
Post: RE: Rotate 2D Gaussian given parameters
| (Dec-10-2020, 06:37 PM)ndc85430 Wrote: Can't you make use of a rotation matrix? For each point (x, y) the rotation matrix would give you new points (x', y') and then you simply compute f at those ne... |
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schniefen |
General Coding Help |
4 |
2,896 |
Dec-10-2020, 06:44 PM |
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Thread: Rotate 2D Gaussian given parameters
Post: Rotate 2D Gaussian given parameters
| I have a Gaussian function of the form:
def f(x,y):
a=some number
b=...
c=...
return 3*np.exp(-a*(-0.5 + x)**2+b*(x-0.5)*(y-0.5)-c*(-0.5 + y)**2)This is a Gaussian function symmetric around ... |
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schniefen |
General Coding Help |
4 |
2,896 |
Dec-10-2020, 06:17 PM |
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Thread: Plotting “simple” diagram with gridlines at specified intervals
Post: RE: Plotting “simple” diagram with gridlines at sp...
| (Dec-03-2020, 11:46 AM)schniefen Wrote: I’d like to plot a diagram according to the sketch in the link. The lines emanating from the y-axis should be dotted, and the boxes above the x-axis are suppo... |
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schniefen |
General Coding Help |
1 |
2,407 |
Dec-03-2020, 05:54 PM |
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Thread: Plotting “simple” diagram with gridlines at specified intervals
Post: Plotting “simple” diagram with gridlines at specif...
| I’d like to plot a diagram according to the sketch in the link. The lines emanating from the y-axis should be dotted, and the boxes above the x-axis are supposed to be squares. The square enclosed by ... |
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schniefen |
General Coding Help |
1 |
2,407 |
Dec-03-2020, 11:46 AM |
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Thread: How to plot level surfaces
Post: How to plot level surfaces
| This is a nice introduction on how to plot level curves given a function z=f(x,y), i.e. via plt.contour. Is there an extension to this in 3D? I'd like to plot some surfaces of C=f(x,y,z), where C is a... |
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schniefen |
General Coding Help |
0 |
1,640 |
Nov-19-2020, 07:08 PM |
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Thread: Getting largest indices of array less than or equal to an array of numbers
Post: RE: Getting largest indices of array less than or ...
| Current solution:
y_i=np.linspace(np.zeros(d),np.ones(d),m+1)
y=np.random.uniform(0,1,d)
ind=np.zeros(d)
for k in range(d):
k_i=y_i[:,k]
i=np.argmax(k_i >= y[k])
in... |
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schniefen |
Homework |
5 |
2,616 |
Nov-02-2020, 08:14 PM |
