# Questions tagged [numerics]

Questions on the numerical functions of Mathematica, implementing numerical methods and numerical computing with Mathematica.

1,844 questions
Filter by
Sorted by
Tagged with
73 views

### Why does Mathematica store numerical values in a fresh kernel?

For some reason, when I try to do a computation in a fresh kernel, MM remembers the "old" values from the old kernel, is there a way to stop this?
122 views

### How to numerically solve this system?

Our system: \begin{align} \dot S &= \mu -\beta_1 S I_2 -\beta_2 S J-\beta_3 S A - \nu S\\[2ex] \dot {I_1} &= p \beta_1 S I_1 +q \beta_2 S J +r \beta_3 S A + \xi_1 J- b_1 I_1 \\[2ex] \dot{...
142 views
+100

85 views

87 views

### NSolve unable to solve system of equations with domain specification

I have a system of two equations in two unknowns that I would like to solve with NSolve within a specified region. However, while Mathematica solves the system if I omit the domain specification, it ...
59 views

### Issues with Nintegrate - different methods yielding different values (both giving warnings)

I am integrating the following function \begin{equation} \frac{1}{2d^{2}}\times\frac{\sqrt{\omega_{c}\left|t_1-t_2\right|}-\sqrt{\pi}e^{\frac{1}{\omega_{c}\left|t_1-t_2\right|}}\text{erfc}\left(\frac{...
73 views

### Plotting with NMaximize

I have the following: ...
62 views

### surprised Rationalize will sometimes leave a Real unchanged [closed]

I was surprised that Rationalize will sometimes leave a Real unchanged even if the fractional part of the Real is well above zero. ...
99 views

109 views

### FindRoot with a big range

I have a variable sig that is related to the variables (b,zQ,zh) given by torootsig, so I ...
126 views

In the open source Mathematica implementation called Mathics, an issue was raised where Mathics computes Rationalize[-11.5, 1] as -12 rather than Mathematica which ...
55 views

### Numerical Investigation of two Component Reaction-Diffusion System with Perturbative Advection

I am given two coupled differential equations and try to analyze them numerically because as far as I know, there is no analytical solution known(only the steady-state on an infinite domain is known, ...
86 views

### Nested NIntegrate over a region: Numerical Integration not converging

I need to computed two double nested numerical integrals, of which one is defined over a specific region (e.g. a pentagon). I've tried to use a single NIntegrate with four variables, but the result is ...
64 views

### Composite function derivatives

I would like to calculate the numerical partial derivatives (numerical gradient) of this function: ...
76 views

### MeijerG function: numerical evaluation of its derivative

Mathematica does not evaluate the derivative of the following MeijerG function. ...
160 views

### NonStandard finite difference for BMBB equation

I am trying to implement the following scheme mentioned in the paper "NUMERICAL SOLUTIONS OF BENJAMIN-BONA-MAHONY-BURGERS EQUATION VIA NONSTANDARD FINITE DIFFERENCE SCHEME " What is ...
300 views

### How to ask Mathematica to subtract each adjacent pair in a list, and then, sum them?

If I have a list of numbers as (the number of elements in this list is even) list={1,23,32,54,65,76,87,98,109,110,...} How can I ask Mathematica to subtract each ...
54 views

### logit ScalingFunctions

Having learned how to make symlog axes in this question, I was interested in the logit scale, the transforms of which are ...
Problem setup: I'm trying to solve the following, quite hairy, first order BVP problem, with four unknown functions $\phi, \theta, p_\phi, p_\theta$, and boundary conditions at \$\phi(0), \phi(1), \...