# Tagged Questions

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

391 views

### Wrong result of simple math calculation. Is it possibly a bug of the program? [closed]

I encounter the following issue accidentally (shown in the screenshot) which is very odd to me. The output[4] and [5] is obviously wrong. But with the input value of 991.91, it turns out to be right (...
71 views

### How does Plus work on machine precision Real arguments?

I thought Kahan's summation method would make a nice example for students to use to think about round-off error [W. Kahan, Pracniques: Further Remarks on Reducing Truncation Errors, Commun. ACM 8  (...
113 views

### How can I increase the precision of my computation?

How can I increase precision up to 15 digits for the results (EC, and that of FindRoot) computed below? ...
139 views

### Chopping matrix elements, real or imaginary

An undesired shape of a matrix has the following form: which is created by ...
208 views

105 views

### Unexpected behavior from Accuracy

This is my code Table[With[{x = 10^n + 1/17}, N[x, {Infinity, 5}]], {n, 0, 5}] // Column Or like this ...
47 views

### System of ODEs - NDSolve issues

I am a self-taught beginner trying to use Mathematica for the first time. If you wouldn't mind, I would like to ask for help with the code I am working on as I keep running into multiple issues when ...
104 views

### Compilation, square roots, and integers

After looking at this question, particularly this answer, I wrote my own performance test, using the two functions ...
130 views

Bug introduced in 10 and persists through 10.3.1 or later I created this InterpolatingFunction, and NIntegrate gives an ...
395 views

### Bug: Wrong results from NSolve on coupled polynomials. WorkingPrecision->Automatic fails

OP UPDATE: I received an email from WR on 1-18-2016: "...It does appear that the NSolve function is not behaving properly in this case and I have forwarded an incident report to our developers with ...
58 views

### Error message when using a compiled function in NSum [duplicate]

Below is a simple example to illustrate the problem test = Compile[{{n, _Integer}}, n] Now, Table works fine ...
71 views

### EvenQ not working properly on IntegerPart[real number]

Something fascinating is happening at the moment. ...
89 views

### singularity in boundary value problem

I am trying to solve a non linear differential equation with variable parameter. ...
588 views

### more numerically accurate inverse matrix

I encountered the following matrix mat = {{2, 2.161209223472559 + 1.682941969615793 I}, {2.161209223472559 - 1.682941969615793 I, 2}} and ...