# Questions tagged [warning-messages]

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### Error on DSolve

I've been trying to solve this initial value problem using 'DSolve[]': $$\frac{dy}{dt}=1+t\space \sin(t\space y),\quad y(0)=0, \quad t=[0,2]$$ ...
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### How can I fix my double pendulum differential equations?

Double pendulum simulation ...
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### Getting warnings when I try to numerically solve a diffusion equation

I am trying to solve the diferential equation for diffusion: $\qquad dt(u)=A\,dx(u^m\,dx(u))$, where $m$ is the difussion coefficient. In this case, I am trying to make $m$ a function of $x$, and ...
145 views

### Finding polynomial coefficients returns Tag Plus is Protected

I'm trying to find the coefficients of a polynomial $P(x)$. Please see following equation. $$P(x+2)+P(x-2)=2x+8$$ CoefficientList[P(x+2)+P(x-2)=2x+8,P(x)] However ...
28 views

### Problem initializing xTensor package

I am using Mathematica 12.2 on Windows 10 and I am using the xTensor package for my tensor calculations. However, since today, I cannot run the xTensor package. I get the following error. Can anybody ...
57 views

### Too small to represent and Chop in inaccessible algorithm

Overview I want to apply a specified Chop function to every step in an function call in Mathematica (in my case LegendreP), ...
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### Trying to solve a PDE — getting warnings I don't understand

Consider the partial differential equation ...
70 views

### List Plot Error [closed]

I've produced this simulation of a superhetrodyne radio receiver. I'm pretty sure it's solid for the most part but I'm getting a list plot error. ListPlot::lpn: {{{1.,0.},{2.,0.00104953},{3.,0....
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### How to solve this linear complementarity problem with NDSolve or other functions? The arguments should be ordered consistently

I want to find a numerical solution of $\omega(t,q)$, where $t\in[0,T]$ and $q\in[0,N]$. $q_t$ is a determinstic w.r.t $t$, other unmentioned parameters can be fullfilled or given by the user. I met ...
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### Result is correct, but LinearProgramming spits out lpnn warning in RegionPlot

Sorry if this is a newbie question. I wrote a function to decide if a given vector is in the convex hull of another set of vectors using linear programming. ...
102 views

### What makes a system be differential-algebraic equations?

I am trying to solve the equations in the following way: ...
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### How to avoid machine underflow for plotting and integrating?

I am trying to integrate the following integrand, which I have plotted: ...
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### “ Unable to find initial conditions that satisfy the residual function within specified tolerances”

I know that there are similar questions on stack exchange. However, I am relatively new to mathematica, so I couldn't really understand the answers. Sorry. Here's my code: ...
59 views

### Error message when solving simultaneous differential equations

I am trying to solve the following set of differential equations to obtain $\phi[t]$, $y[t]$, and $z[t]$. The 3 differential equations are here: ...
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### NIntegrate::ncvb: NIntegrate failed to converge to prescribed accuracy

The integration is: ...
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### Evaluate the NDSolveValue at the condition point with replacement [closed]

I try to Evaluate something with replacement ...
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### How to replace the expression in nest?

I need to calculate the following function with replacement in recurrence ...
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### Confused by result of NDSolve for Second-Order nonlinear ODE

It is impossible to solve numerically a nonlinear second-order equation, although the initial conditions are given. ...
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### Error message when referring to the value of a part of one element in a list [closed]

The following works fine to define an element of a two-argument list: T[1, 2] = {3, 4, "yes"} But when I try to change the third part, like this ...
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### Manipulate giving errors when I plot the product of a step function and a continuous function

Riemann's prime counting function J (link) takes half-values at every jump-discontinuity. So, I define it thus: ...
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### Problem with stopping NDSolve after a condition is met

I'm trying to write a piece of Mathematica code that is essentially a differential equation solver that needs to take a specified function $V[t,q]$, and then numerically solves the differential ...
142 views

### Error message: “-1.99992 cannot be used as a variable” [closed]

could anyone please tell me how to fix this: I want to plot the solutions of a coupled ODE: \$\frac{1}{3} u\partial_x ^3 u = \frac{1}{2} \partial_x v; \ \partial_x\left( u \partial_x v - \frac{1}{2} u^...
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### Integral involving orthogonal functions (quantum harmonic oscillator eigenstates)

I have a question about the capabilities of the Integrate command for general parameters. We know that there is a system of functions: ...
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### Serious Startup Error: Error code 603. What to do?

So my laptop shut down due to lack of battery with some open Mathematica notebooks that were saved but now Mathematica wont launch at all and I cannot find anywhere information about this error code. ...
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### Why is this integral throwing a “MemoryAllocationFailure” error?

The following call to NIntegrate throws the error: Throw::sysexc: Uncaught SystemException returned to top level. Can be caught with Catch[[Ellipsis], ...
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### How to know, which constraint is being violated in linear programming problem?

my task is to minimize costs of dispatching various power plants in order to meet demand in a transmission grid. I solve the task as a linear programming problem with the help of Minimize[] function ...
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### How to fix a ParametricNDSolveValue? - Encountered non-numerical value for a derivative at t == 0

How to fix a ParametricNDSolveValue? - "ParametricNDSolveValue::ndnum: Encountered non-numerical value for a derivative at t == 0." I have tried ...
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### FindRoot does not satisfy PrecisionGoal but gives no error message

I use FindRoot to find a root to the equation ...
61 views

### Syntax error using Plot

Why is the error coming and what should I do to resolve it The code is ...
126 views

### Can't be solved using methods available

I'm stuck on this and chagrined I'm even asking, but this: ...