# Search Results

Results tagged with Search options user 57
9 results

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

This looks like a numerical precision issue. Various approaches that precisely address this, all yield the same, correct solution: Scaling of the x values: data = {{0, 20}, {20, 10}, {40, 5}, {60, 2 …
modified Jan 27 '16 by Sjoerd C. de Vries
I modified your NDSolve a bit for convenience (NDSolveValue to get rid of the rule, and f instead of f[p] to get a pure function): s2[σ_] := NDSolveValue[{f''[p] - 2 f[p] f'[p] + (1 + d/2) f[p] + ( …
modified Oct 17 '15 by Sjoerd C. de Vries
Welcome in the amazing world of machine precision arithmetic! If you examine the binary representation of both numbers you see the following: RealDigits[1.2, 2] (* {{1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, …
modified Jul 13 '15 by Sjoerd C. de Vries
In addition to bill's version, which is probably what I'd do as well, another reasonable possibility would be: Table[ NSolve[-y*16 x^3 - y^2*25 x^2 + 5 == 0, x], {y, {0.1, 0.2, 0.3, 0.4, 0.5, 0 …
modified May 25 '13 by Sjoerd C. de Vries
If the function is not to wild Interpolation could be of use: t = Table[{x, f[2, x]}, {x, 0, 4, 1/10000.}]; it = Interpolation[t] Large values of second derivatives are probably caused by discontin …
modified Nov 18 '12 by Sjoerd C. de Vries
You are talking about a list of 3D points and curve fitting. I therefore assume you want a function with a single parameter that describes a curve fitting through your set of points. I don't believe L …
modified Sep 5 '12 by Sjoerd C. de Vries
If you use inexact constant in your equation it helps if you increase their accuracy as well. You can do that easily using the backtick notation: z[x_, y_] := Exp[Sin[60.0200*x]] + Sin[50.0200*Exp[ …
modified Jul 1 '12 by Sjoerd C. de Vries
With the current setup you get three different answers: testTable // Union (* ==> {0.001242846719, 0.001242850670, 0.001242854621} *) The problem is that you haven't sufficiently increased the pre …
modified May 21 '12 by Sjoerd C. de Vries
My variant of Szabolcs code. It doesn't need an extra package: sol = First[ NDSolve[eqns, {a, b}, {t, 0, 1000}, Method -> {"EventLocator", "Event" -> Abs[a'[t]] +Abs[b'[t]] < 10^-5, …
modified Jan 22 '12 by Sjoerd C. de Vries