# Questions tagged [scipy]

SciPy is a Python-based ecosystem of open-source software for mathematics, science, and engineering.

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42 views

### handling symbolical and numerical nested integrals

I'm working on reproducing a calculation from this paper https://arxiv.org/abs/1712.03972 for my thesis but I'm struggling with how to properly implement the nested integrals in Python, specifically ...
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1k views

### 10th-order Runge-Kutta Method

I want to apply the 10th-order Runge-Kutta method, but I am having trouble finding the coefficients. I read Ernst Hairer's article, he used the stage s=17 and ...
20 views

### Use of scipy.linalg.cython_lapack.dgbsv in cython script

I was working into accellerating a solver for baded matrix using cython. The base case is the following pure python code : ...
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1 vote
130 views

### Preconditioner Implementation with matrix-free methods (sparse iterative solvers)

How can I define preconditioners (SPILU, SPAI, etc.) for sparse iterative methods (TFQMR, GMRES, CGS, etc.) for the matrix-free left-hand side? I defined $Ax=b$ using matrix-free $A$ (with ...
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### Solve beam equation with elastic term using scipy solve_bvp

I want to solve the beam equation with distributed load and elatic term (which depends on how much the beam interact with the terrain) : $$EI\frac{d^4w}{dx^4}+k*(w(x)-t(x))=q(x)$$ where $q(x)$ is a ...
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1 vote
208 views

### How to run scipy.optimize.minimize with L-BFGS-B for maxiter (completely)

I want to run the below code for maxiter = 20001. I don't want it to stop by some default criteria. ...
55 views

### Find peaks method for finding elusive peaks

I'm currently utilizing the find_peaks function to identify peaks within this spectrum. However, despite consulting similar queries on Stack Overflow, my attempts to incorporate features such as ...
62 views

### How to calculate the numerical integration and plot the result in python?

I am trying to solve the question below in McQuarrie Physical-Chemistry book. The first step of the exercise, I solved. However, the second step involves a numerical integration. I can develop a code ...
85 views

### BSplines from scipy not defined on whole range of the knots

I am looking at the construction of BSplines out of curiosity. I created a small code that uses scipy.interpolate.BSpline to create basic splines. I get the following basic splines for order 0, 1 and ...
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### solve_ivp method=ODE23 time step not decreasing in order

My time step with the function scipy.integrate.solve_ivp is not decreasing in t_span fluctuating (reaching values below or ...
126 views

### Different Results for Double Pendulum

In this study, (Hidden Fractals in the Dynamics of the Compound Double Pendulum) the authors provide various fliptime fractals (of a double pendulum) for different length combinations. However, when I ...
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### scipy exp model fitting: prevent coefficients blowup

I'm trying to fit a few X-Y points that look like exponential. I used the following scipy code: ...
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67 views

### Hyperbolic integral of the second kind

The elliptic integral of the second kind is given by $$E(t,m) = \int_{0}^t \sqrt{1-m \sin(s)^2} \operatorname{ds}$$ and there is for instance a scipy function ellipeinc that computes it. The ...
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### using scipy.sparse.linalg.eigsh for degenerate states in Bose Hubbard model

I am currently writing a code for the Bose-Hubbard model, and I am calculating the ground states and single-particle density matrix for different values of U and J. As U=0, one would see how the ...
153 views

### BFGS Constrained Optimization Failure Due to Precision Loss

I am trying to optimize the following objective function according to some constraints. However, the optimization fails at the first iteration with the message that the desired error was not ...
1 vote
490 views

### optimizing piecewise linear objective functions (perhaps non convex) with equality constraints

When I do my project, I need to optimize piecewise linear objective functions (perhaps non convex) with equality constraints. The piecewise linear objective function may be not convex like this in the ...
109 views

### How to minimize a numerical integration in python?

I need some help to minimize a numerical integration. It's about a classical problem in physics (hydrogen atom). It can be solved analytically but I need to solve it numerically in Python. We have an ...
83 views

### Singular Matrix Error in Incomplete LU Decomposition

I’m currently working on solving the following PDE: $$$$-(\mu_x \frac{\partial^2 u}{\partial x^2} + \mu_y \frac{\partial^2 u}{\partial y^2}) = f(x, y)$$$$ Where a right hand ...
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2k views

### What algorithm(s) do numpy and scipy use to calculate matrix inverses?

I am solving differential equations that require inverting dense square matrices, and I wanted to know what algorithm(s) do numpy and scipy use to calculate matrix inverses?
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### Numerical calculation of Lyapunov exponents using SciPy's built-in solve_ivp

I have previously successfully implemented the QR decomposition method in MATLAB to calculate Lyapunov exponents for Lorenz equations. See here. This method integrates the stacked system, i.e. the ...
• 307
112 views

### How to use a custom OdeSolver in Scipy's solve_ivp

In Scipy's solve_ivp documentation, we see the method argument can be either a string or a user-defined ...
• 307
476 views

### Number of function calls and jacobian calls in scipy.root

Just as an exercise, I am numerically solving the following system of equations: $$$$\begin{cases} x^2 + y^2 = 32 \\ 3x + 7y = 15 \end{cases}$$$$ ...
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178 views

### Solving system of ODEs, where time derivative approaches infinity due top initial condition

I am trying to solve a problem in python using scipy's solve_ivp. The system of ODEs I am trying to solve is for coupled where I am solving for two time-dependent ...
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177 views

### Weights for equidistant samples in power law fitting

I am working on fitting analytical curves to experimental data obtained in real viscoelastic tests (in fact, static creep tests). The setting of the problem is: the experimental data I have is a set ...
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314 views

### 2D integrals in Python with specified points of interest

Note: This is my first question on stackexchange; please tell me if I'm doing something incorrectly. I am trying to calculate a series of a 2D integrals in Python with an integrand that has several ...
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1 vote
321 views

### Using solve_ivp for a PDE: how to handle multiple time-dependent variables?

I am trying to build a Python code that solves a set of coupled differential equations which will be spatially discretized by the method of lines advancing in time. I am planning to use ...
482 views

### Solving IVP backward in time via python

I'm having difficulty solving an initial value problem (IVP) in Python backwards in time. The code is at the end of this post. First, please let me state my simplified problem. The forward IVP is ...
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### Matching the limits of integration with the proper variables in a complicated case when using scipy.integrate.nquad

I need to integrate expressions containing powers of the function: ...
416 views

### Accelerating the computation of scipy.sparse.linalg.expm_multiply

I have a tridiagonal antiHermitian matrix ($-i*Hami*t$) with nonzero elements only along the upper diagonal and lower diagonal, and the goal is to know the action of exponential of such matrix on a ...
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1 vote
146 views

### Possible bug with scipy.optimize SHGO sobol: TypeError: <lambda>() takes 1 positional argument but 3 were given

I have been trying to perform some global optimization with SciPy optimizer SHGO and I've had issues with the sampling method 'sobol'. Specifically, I get an error ...
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### Interpolating 2D data on a hemisphere in order to have $C^2$ function but no overshoot

I am interpolating a 2D dataset on a hemisphere, and I am currently using scipy.Rbf that I like for its simplicity. I am defining the norm of the interpolator with ...
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788 views

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1 vote
803 views

### Finding the parameters of a function via curve fit

I'm trying to estimate the parameters (v, n, k) defined in fit_func. I tried the default least squares fit but I couldn't find the parameters successfully. ...
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