Questions tagged [precision-and-accuracy]
The precision-and-accuracy tag has no usage guidance.
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Mathematica 13 not Working with Windows 11 Pro (bug)
Erratic behavior in Mathematica 13 on Windows 11 Pro. I have two issues that come and go. (1) Sometimes, the equation controlling the manipulate in my notebooks corrupts. The slider bars are not able ...
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How to get correct numerical result without lots of digit precisions?
I am wondering if it is possible to get the correct numerical result without computing with a lot of precisions in expressions.
as a simple example suppose in the middle of some of my numerical code ...
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How to improve accuracy of the integration in the following case?
Consider the following function dsPrimakovdtnucleus:
...
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Incorrect answer zero where correct answer is very large (precision issue)
Define a function F as follows:
F[α_, x_] =
N[Exp[x/2] Abs[Gamma[α/2 + I x /(2 Pi)]]^2, 10];
It is a product of two terms. ...
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Answer changes slightly when re-run
I am trying to resolve why I get slightly different answers when I re-run my notebook. Here is my full code:
...
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How to ensure for a solution of `NDSolve` to be positive?
I'am trying to solve kinetic equation for test particles in the Maxwellian plasma. It is Vlasov equation appended with Landau integral of collisions. It is proven that solution of such an equation is ...
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Increase precision of matrix multiplication [closed]
I am computing U.U......U.x, where x is a vector, U a square matrix and the product involves N times U, i.e., (U^N).x if you like. One way to do this is
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Accuracy and precision control for a simple calculation [closed]
Consider a very simple calculation: $231 \times (2.54) ^ 3$, which is the number of cubic cm in a US gallon.
On my phone app calculator I got the exact answer, which is $3785.411784$.
On Mathematica, ...
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How do I speed up this numerical integration with Bessel functions? (Tried changing Working Precision and Integration Strategies)
I need to compute the function P[b] given as follows:
...
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Accurate and efficient sampling of interpolated functions
Suppose we are given two interpolated functions
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LinearOptimization and Accuracy
Surprised to encounter the following issue in handling Accuracy with LinearOptimization:
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Is there any alternative for conditional plot that gives a more precise result in a shorter time?
I have the given function $Func$ and want to have a plot of those domains where $-3\leq Func\leq 3$ in precise details. I am using ...
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How to handle "too small to represent as a normalized machine number" when plotting a figure [duplicate]
I am trying to plot a figure by the following codes:
Plot[(27 2^((-2 + a)/(-1 + a)) 5^(a/(-1 + a)) 7^(1/(1 - a))
a^2)/((-1 + a) (4 + 9 a)), {a, 1.001, 3}]
...
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Equality of almost equal lists
Can you help me with this common problem I have?
Given two lists:
a={339.66666666666697`, -287.4444444444446`, 0.`}
and
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Interval Arithmetic when calculating eigenvectors
Consider the following matrix with entries being intervals
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How to prevent Mathematica from rounding some PDF values to 0?
Dear Mathematica community,
I'm having a problem with the PDF function for the hypoexponential distribution. Specifically, Mathematica returns 0 as soon as the value is very small. Below is an example:...
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Using FindRoot and having problems with $MaxExtraPrecision
I'm trying to find the roots of the function radial, written below. And to make this, I'm using the function \[Omega]ini to ...
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Kahan Compensated Summation
Is there an example/library that implements Kahan summation in Mathematica for matrix-matrix/vector-matrix multiplication?
Having some trouble adapting something like this Compilation of Total with ...
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FindShortestPath failing with All even when GraphDistanceMatrix succeeds
Shortest Path routines are commonly used within more complex optimization methods that work to ensure there are no negative cycles even when there are negative weight edges. Often there are 0 weight ...
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Am I losing precision in manually entered equations?
I am using the following code to calculate the two solutions of a quadratic equation in the variable t.
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Floating point precision and speed [closed]
I am attempting to understand how to speed up the evaluation of numerical expression.
Specifically, following the first point of this blog, Mathematica is much quicker dealing with floating-point ...
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Solution gets worse as I increase Precision and Accuracy goals
I am numerically solving the following ODE below.
If I set AccuracyGoal and PrecisionGoal both to 10 I get a solution that makes sense: constant and then damped oscillation.
However, all things equal, ...
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IntegerPart - is this a known bug?
I'm working in Mathematica 13.0 and I type
a=0.00001;
IntegerPart[a/a]
and well, the output is 0.
Try with almost any other value of ...
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Discrepancies in NDSolve Solution Between 4D and its Reduced 3D Counterpart
I have two systems, a 4D system and a 3D system. The 3D system is a reduction of the 4D system in such a way that:
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Mathematica ignores precision requirement when evaluating a Legendre function
Bug persisting through 13.1.0 [CASE:4953269]
When attempting to calculate a certain associated Legendre polynomial within a given precision, Mathematica seems to ignore it if the argument is ...
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How to improve the accuracy of integration with Bessel function without significant drop in performance?
Consider the following function and integral:
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Adding numbers with defined precision produces incorrect result
I've tracked a bug in my code down to the problem of adding two numbers together, with the left argument having machine precision, e.g by 3` . The issue is, if ...
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What does standard deviation mean when using Predict[]?
I am using the Machine Learning function Predict[data, Method -> "DecisionTree"], and I am trying to get the most accurate measurement of its accuracy. ...
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2
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Why this integral gives zero?
I would like to compute this integral for a =100, ... ,1500
$$ \int_1^\infty \dfrac{\left(x^2-1\right)^{3/2}}{x} \,e^{-ax}\, dx $$
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Controlling accuracy for code
So I have a lot of trouble controlling precision and or accuracy with Mathematica. I have tried reading up for it but in the end I get even more confused. Here is my code, it is a little long but it ...
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NIntegrate fails to converge to desired accuracy
I am calculating an integral with Mathematica. This is the code I am using:
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Issues with ConvexOptimization and SetPrecision
I am completely new to Mathematica (second day), so do not expect things to look polished.
I am trying to perform a ConvexOptimization over a List/Array (dimensionality ...
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Plotting high precision high degree polynomial
When I plot a high degree polynomial such as (available as CloudObject since it is too big to explicitly include):
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Divide by zero warning: Actual division by zero or spurious?
I have the following code that calculates the gain of an amplifier
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Error "is too small to represent as a normalized machine number; precision \ may be lost " for small values in Plot
I'm trying to plot two curves but I'm having issues with the lower end of the range:
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What's the best method to use when NIntegrating a sinx + cosx type function?
I'm having some problems when trying to NIntegrate a sinx + cosx type function. I have already tryed several combinations of ...
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Confusion about precision [duplicate]
When I evaluate
x = 1.0000000000000000001 (* Precision of 20 digits *)
Mathematica returns
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long division acurate answer on dividing long numbers [closed]
ok but first of all if i have the huge number to be divided what will i have to use for the division to be accurate long division or some other formula square root or 2 this is to calculate music ...
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Real number equality (==) not working: what's the least-overcomplicated solution?
I'm running a program that evaluates equalities after I substitute all symbols for numbers. The equalities on floats are giving me trouble. My program is reaching a point where something like the ...
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How do change precision in coefficients in matrices
I alway have this kind of matrices...
obviously I would like to have 0s instead of 10^-15. I've tried with N[] function but doesn't work. Does anybody know how to proceed in this case?
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Is the result given by NSolve sufficiently reliable to claim that there is such a solution for the equation?
I use this code for ContourPlot
...
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Which result is more reliable in NMaximize in the given code? with `WorkingPrecision` or without it?
I have two functions $ f(x,y) $ and $ g(x,y) $ over the domains $ 1<x< 2$ and $0<y<\pi$. I use ContourPlot to ses those values of $(x,y)$ for which $g(...
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How to calculate the maximum value of $x $ which satisfy the conditions $g(x,y)=0$ and $f(x,y)>1$?
I have two functions $ f(x,y) $ and $ g(x,y) $ over the domains $ 1<x< 2$ and $0<y<\pi$. I use ContourPlot to ses those values of $(x,y)$ for which $g(...
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NSolve and FindRoot give a value which is not correct; how can I obtain the exact solution of the given equation? [closed]
I have two functions $ f(x,y) $ and $ g(x,y) $, I use this code
...
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Crashing mathematica 12.3 with a simple ODE
I'm trying to solve an ODE using the following code:
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RegionMember command alternative that can check members exactly?
My problem is as follows:
I have an exact rational polygon created using ConvexHullMesh and given a rational point I need Mathematica to decide exactly if it is ...
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Accuracy issue in computing a Markov Transition Matrix
this question is based on a previous post of mine. I am simulating a one-dimensional Markov process on a linear graph. Transition probabilities are different than zero only for nearest neighbours of ...
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