Questions tagged [precision-and-accuracy]
The precision-and-accuracy tag has no usage guidance.
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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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2
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71
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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):
...
- 3,553
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1
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76
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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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2
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142
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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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3
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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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1
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66
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Confusion about precision [duplicate]
When I evaluate
x = 1.0000000000000000001 (* Precision of 20 digits *)
Mathematica returns
...
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-3
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1
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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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335
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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
...
- 463
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34
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How to obtain the most accurate maximum value of the given equation? Changing WorkingPrecision gives different results
I have two functions $ f(x,y) $ and $ g(x,y) $ over the domains $ 1.56 <x< 1.6$ and $3<y<\pi$.
...
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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(...
- 463
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2
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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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82
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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 ...
- 553
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2
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92
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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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42
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How to set up precision by default?
I have a table computing many numbers with large precision. Because of this, probably, Mathematica consumes a lot of RAM. Is it possible to restrict the precision in any calculations by default (...
- 3,544
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How to make Mathematica work only with 10 digits? [duplicate]
I have a quite frustrating problem.
In my code, I need Mathematica to ignore everything after 10 digits.
For example I need it to treat:
25.26011447795545 as ...
- 553
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1
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51
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2
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0
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Rational numbers in NDSolve
Is it possible to use NDSolve with Rational numbers instead of Real?
I use all rational ...
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1
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60
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Which one is more accurate Solve or NSolve? How can I get the same result as Solve using NSolve in the given code?
I am using this code to calculate the quantity $sol$. Using Solve, I get the result $9.8598$
...
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2
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628
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How to force Mathematica to do infinite-precision calculations?
Consider the following calculation:
1234*5678*90.12
The result is:
6.31439*10^8
However, I want to get a precise result. Of ...
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35
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Precision Issue in LinearOptimization - dual solution is not feasible
Trying to solve a linear program with high precision requirements and am interested in both the primal and the dual solution. Prefer solving the primal problem for convenience and solving the dual ...
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Avoid Extrapolation When Using NMaximize on Interpolating Functions
I want to use NMaximize to find the maximum value given by one interpolation function with respect to a constraint given by a second interpolation function. The main problem is that NMaximize produces ...
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Mathematica 12.1: Evaluation result does not show decimals [duplicate]
It surprises me that Mathematica does not show decimals after evaluating the following calculations:
500000+5.05
Result: 500005.
Expecting: 500005.05
...
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102
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Nonlinear model fit gaussian precision
I wanted to fit double gaussian but it doesn't work, it doesn't fit gaussian. The error I get:
Data:data Here is code
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2
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44
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`KernelMixtureDistribution` error message about precision
I want to use KernelMixtureDistribution to deal with a large amount of data points. For example, the following codes shows how I use it:
...
- 463
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42
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Why is the `N` function giving me the wrong result when using WolframScript? [duplicate]
I am using wolframscript.exe to learn mathematica and I would expect the following code to return 0.7071:
...
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52
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Why it remains only one digit after point in this numerical computation?
Why? And why N doesn't help?
How to change and/or make it permanent?
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1
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59
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"Sparse" Overflow error in NIntegrate
I want to evalutate an integral
$$I = \int_{-0.01}^0 \int_{-0.01}^0 \left(\frac{1}{\sinh|t_2+t_1+T| \sinh|t_2+t_1|}\right)^{2/m} \left(\frac{\sinh|2t_1+t_2+T|}{\sinh|t_1+T|}\right)^{1/m} \left(\frac{\...
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NIntegrate::zeroregion error outside the integration domain
I am trying to integrate a function
$$\int_R \frac{1}{(\sinh|T-t_1+t_2|)^{\frac2m} (\sinh|t_1-t_2|)^{\frac2m}} \left(\frac{\sinh|t_2|}{\sinh|t_1|}\right)^{\frac1m} \left(\frac{\sinh|T-2t_1+t_2|}{\sinh|...
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Wrong limit appears [closed]
Consider the following limit
$$
\lim_{x\to-\infty}x-\sqrt{x^2+7x}
$$
Going through some algebra leads to
$$\begin{align}
\lim_{x\to-\infty}x-\sqrt{x^2+7x}&=\lim_{x\to-\infty}\frac{(x-\sqrt{x^2+7x})...
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Mathematica returns zero for small rational number to 1/133 power but not zero [closed]
This small number raised to the 1/133 root is not zero but Mathematica is underflowing with the computation. I assume Mathematica is first computing the quotient numerically, then taking the root:
<...
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59
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Minimizing a quadratic form: Failed to converge to the requested accuracy or precision within 100 \ iterations
I'm trying to minimize this type of quadratic form:
...
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88
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How to calculate precise higher derivatives of ParametricNDSolve solution
Higher Derivatives of NDSolve don't match the results from DSolve solution, can I somehow increase the accuracy of numerical method to match arbitrarily high derivatives?
Equation
I am using ...
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Issues with Nintegrate - different methods yielding different values (both giving warnings)
I am integrating the following function
\begin{equation}
\frac{1}{2d^{2}}\times\frac{\sqrt{\omega_{c}\left|t_1-t_2\right|}-\sqrt{\pi}e^{\frac{1}{\omega_{c}\left|t_1-t_2\right|}}\text{erfc}\left(\frac{...
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Same integral yielding to different results
I am currently working with the following integrals
\begin{equation}
\int_{0}^{\infty} dk\thinspace \frac{k^{3}e^{-2kd}}{\omega^{2}+k^{4}} = \frac{1}{\omega^{2}d^{4}}\int_{0}^{\infty}d\epsilon\...
- 499
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plot and limit are not in agreement [closed]
I am plotting the following function $\frac{\sqrt{t \text{$\omega_c $}}-\sqrt{\pi } e^{\frac{1}{t \text{$\omega_c $}}} \text{erfc}\left(\frac{1}{\sqrt{t \text{$\omega_c$}}}\right)}{(t \text{$\omega_c$}...
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52
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About Numerical Precision Related with Zeros [duplicate]
I encounted the following precision issue. I define c = a + b, but the result for 'c - a - b' does not equal zero. I am not sure how to resolve this.
'''
...
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2
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199
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How can I make sure that there are real roots for the given function? Can I trust the plot only?
I have this function
$$f(x)=(\pi -2 x)^2 \sin \left(\frac{\pi ^2}{2 x-2 \pi }+\frac{1}{2} \csc ^{-1}\left(\frac{4 \pi (\pi -x) \csc \left(\frac{\pi ^2}{x-\pi }\right)}{4 (\pi -x)^2+\pi ^2}\right)\...
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35
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61
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Precision problem with mathematica
I have a precision problem with a complicated function in Mathematica. I need to get norm (NIntegrate[f[x],{x,0,1}]) and shape (...
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SetPrecision with Manipulate using variable number of controls
I want to convert inputs from controls in Manipulate into exact numbers and have two kinds of inputs:
parameters: there are a fixed number of these
rates: the number of rates is controlled by the ...
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60
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Mathematica accuracy errors when creating data
I created training data for a neural network and below are two errors I got
The only code that uses "FindRoot" command is the following
...
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94
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General:munfl error problem
I have the following function, that is the result of The integration between x and some upper limit of a positive function, thus should be positive
$f(x,vE) = \frac{e^{-1140.09 x} \left(e^{67945.5 \...
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How does WorkingPrecision in NDSolve handle MachinePrecision?
I'm wondering why the following code
NDSolve[{y''[t] + y[t] == 0, y[0] == 1., y'[0] == 0}, y, {t, 0, 10},
WorkingPrecision -> 6]
throws the error/warning, that ...
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111
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DiscreteMarkovProcess: preparing the transition matrix and unexpected negative results
I would like to implement a Markov process.
It consists on a walk on a one-dimensional lattice, with nodes spaced $\epsilon$ from $-2$ to $2$.
The transition probabilities for $x \neq y$ are as ...
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