# Tag Info

## Hot answers tagged numerical-value

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### Is Internal`StringToDouble broken in 12.3?

StringToDouble was renamed StringToMReal as part of code cleanup and the addition of several friends: ...
• 13.7k

### GroupBy twice gives different results

Quit the kernel before each test. This is on MMA 10.3 on Mac OS X. Simplify the problem We can simplify so that tmp is much much smaller and easier to analyse: <...
• 5,987

### GroupBy twice gives different results

It looks like a problem of numeric cache: ...
• 43.1k

### Numerical voodoo in mathematica?

To get exact output, use exact input (and please input your question using plain text Mathematica code that one can easily copy). ...
• 116k

### Solve Laplace equation in Cylindrical - Polar Coordinates

Here is a analysis of all the problems related to Mathematica in your question. Briefly summarized, These are 3 problems : the lack of build-in tools to visualize the potential and vector field in ...
• 17.1k
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### Solve Laplace equation in Cylindrical - Polar Coordinates

I think it is better to use Cartesian coordinates because one does not have to deal with the periodicity in p. To have control on the meshing of the the region, we tell Mathematica explicitly to ...
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### Why does Abs return negative values?

It is a bug that will be fixed in the nearest release of Mathematica. It affects Abs/Sign of positive Root objects with third argument 1, for which the real root isolation algorithm produces an ...
• 3,245
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### Matching pair of numbers {a,-a}, where a is numeric

lst = {{2, -2}, {1, 5}, {1, -3}, {-3, 3}}; Pick[lst, Total[lst, {2}], 0] {{2,-2}, {-3,3}} ...
• 351k

### Could I define 0^0 to be 1?

Yes, by doing this (similar to this): Unprotect[Power]; Power[0|0., 0|0.] = 1; Protect[Power]; If you want to revert to normal: ...
• 31.2k
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### How to obtain numerical solutions of a two-variable equation?

There are infinitely many (continuum) solutions and basically one cannot list them all e.g. because of the Cantor theorem. This is the reason why numerical approach is unsatisfactory. However we can ...
• 54.6k

### Numerical voodoo in mathematica?

The problems at hand comes from using inadequate numerical approximation. The equation behind is quite simple and it can be solved exactly, we put 10/3 instead of <...
• 54.6k
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### How to find and express all polynomial roots with greatest precision?

Your numericRoots are OK. The core of your problem is that you use Expand to put your polynomial into power series form. High order power series are numerically unstable. The form your z function ...
• 13.6k

### What is the fastest way to compute digits of $\pi$ using Mathematica?

direct implementation of Chudnovsky formula for reference: ...
• 38.5k
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### Is it possible to ask Mathematica to give the maximum value of a function over a specific domain?

NMaximize[{f[n], 1 <= n <= 10^6, n ∈ Integers}, n] (* Out: {63.041, {n -> 2}} *) You can then get the corresponding symbolic function value using your ...
• 63.1k
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### Problem with NDSolveValue

I will present an anisotropic meshing solution that will allow you to resolve a sharp normalized peak at the center of your cube. Many links applying this technique are in my answer to the question ...
• 16k
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### Some Strange results from MMA and Matlab

The line Table[N[PHI30EQ[u], 30], {u, 0, 0.1, 0.001}] doesn't do what you think it does. You're asking for 30 digits of precision, but you supply ...
• 19.2k

### NDSolve giving a wrong solution

The general problem In using NDSolve to solve first-order IVPs, there are basically two ways to set up the ODE: ...
• 222k

### Why does N[Re@f] give complex result?

I think your problems are made by order of appling Re and N. Re@Bloch is not yet a state ...
• 5,115
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### What is the fastest way to compute digits of $\pi$ using Mathematica?

Here is an adaptation of MATLAB code from Trefethen, Ten Digit Algorithms (2005), based on Borwein & Borwein, The Arithmetic-Geometric Mean and Fast Computation of Elementary Functions (1984) that ...
• 222k
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### Error and uncertainty propagation: Is using Precision/Accuracy a sound strategy?

Your problem is similar to a wave spectra problem and a regression problem, and I have both types of problems going on at work right now which is why I've thought about your problem a bit. Here is an ...
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### N[..., 5] does not returns what I expected

The documentation for N says that N[expr, n] attempts to give a result with n-digit precision. In the Wolfram Language, or any ...
• 9,971
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### Why does N[Re@f] give complex result?

Update: I think this is a numeric precision problem rather than a matter of the behavior of Re. I don't know if I should leave my original answer below for ...
• 265k
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### How to make an Histogram where the data are strings?

BarChart[Counts[{"a", "a", "b", "c"}], ChartLabels -> Automatic] By using Counts instead of ...
• 20.3k
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### How to plot output data of Do-command?

This is a good candidate for NestList ...
• 34.6k
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### Comparing exact expressions vs real numbers

PossibleZeroQ is rather fast and does precisely what you're looking for: RepeatedTiming[PossibleZeroQ[a - b]] {3.2*10^-6, ...
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### 1-D PDE with nonlinear ODE as boundary condition

NDSolve currently can't handle coupled PDE and ODE, so let's discretize the system all by ourselves, but before that, I'd like to point out the system actually has ...
• 55.3k
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### Why mathematica does not solve the equation $x\left \lfloor x \right \rfloor=10$ for $x$?

You can specify you want real solutions Solve[x*Floor[x] == 10, x, Reals]
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