Questions tagged [machine-precision]
For questions on the use of machine-precision real numbers (also known as floats), the numbers that can be directly manipulated through the underlying numerical capabilities of your computer system.
229
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How to set the precision for the entire notebook
I want to do various computations conditional on a given precision for the entire notebook. I use the following code:
...
- 5,490
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1
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When does arithmetic with approximate numbers not follow basic properties? [closed]
Consider this:
x = Exp[3.5*^15]
(* OVerflow[] *)
The above is well documented and so is the next result.
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46
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Evaluation gives different results before and after simplifying expression
I am trying to evaluate $h(z)=\frac{f(z)}{g(z)}$ at points $z$ close to 0. Here I have taken an example value of $z=\texttt{z1}=10^{-7}$ for demonstration. I notice that evaluating the fraction before ...
- 121
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2
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92
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Generating sequence from a number with Precision
This question was from the End-Semester question paper of the previous year of my Course on Wolfram Mathematica - Apparently when I try to code it, something is going wrong with respect to Precision - ...
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53
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Delayed evaluation of nested functions
i am new to Mathematica. Here is the situation:
I have a exponential function of n,t that I want to calculate integral over t ...
0
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1
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106
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Exp[-690255.2204176334] is too small to represent as a normalized machine number; precision may be lost [closed]
I'm trying to visualize the relationship of maximum temperature $(T_{m})$ with the heating rate with Randall-Wilkins theory for an energy depth of 0.85 eV. The Randall-Wilkins expression used is ...
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54
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Overflow + Underflow Problems with Code
I am trying to use Mathematica to verify simulation results with an analytic result.
The analytic results are performance measures of the M/D/1 queue, which unfortunately uses
the factorial function ...
- 427
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2
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106
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Precision problem in DensityPlots
I need to perform a DensityPlot, but the figure is partially displayed. The codes and figure are shown below.
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3
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104
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How to modify the given codes (NIntegrate of Boole) to get the most accurate result possible?
I have five conditions con1 to con5 over the two-dimensional domain $t,u\in[o,2\pi]$. I want to compute this area $(con1 \cap con2 )\cup(con3 \cap con4 \cap con5)$ numerically. I try the two codes ...
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How to modify NIntegrate code below so that it gives the most accurate/reliable numerical result?
Imagine that I have two conditions con1 and con2 over the two-dimensional domain $x,y\in[-2,2]$. I want to compute the area of the union of these two conditions i.e. the region $(con1 )\cup(con2)$. I ...
- 349
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351
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Table does not give expected result with `30 but right with `40
I want Mathematica to generate a table, but I am very confused by its behaviour.
tab = Table[i, {i, 6.311, 6.312, 0.001}]
Now I get the desired result, namely {6....
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434
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33
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98
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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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254
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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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75
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1
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192
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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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9
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315
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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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2
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164
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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 ...
- 557
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71
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Issue with some floating-point errors and not others
Not looking for a solution necessarily, but just trying to understand why this issue occurrs.
I have a 'Do' loop which iterates some algorithm over values of a parameter 'x' with range {x,0,1,0.1} and ...
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1
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226
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How to handle very numbers that are "too small to represent as a normalized machine number"?
I will preface this by saying that I am not very familiar with Mathematica whatsoever. That is why I am asking this here even though I have found a few forum posts that might provide the solution to ...
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2
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2k
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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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1
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143
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Spurious poles in a gain plot (due to machine precision or complex numbers?)
I have the following plot that I like to make. It details the gain of an amplifier.
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1
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350
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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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144
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FixedPoint not working, despite quick convergence of sequence [closed]
Trying the computation below, with Mathematica 13.0.0, I am not getting a result returned.
FixedPoint[Cos, 0.85]
This appears in the 3rd edition of "...
- 315
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1
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131
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59
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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 (...
- 4,652
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2
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46
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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:
...
- 513
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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:
...
- 185
1
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0
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51
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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$}...
- 573
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1
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42
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0
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0
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63
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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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1
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154
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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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43
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ContourPlot3D with small domain produces glitchy mess
I'm able to plot some graphs over small domains, but not others.
For example, this works just fine:
...
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2
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185
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Simplify for precision
I have an a set of equations to solve — details irrelevant — the result of which will be converted into PostScript, a 1980s printer-control language the only floating precision of which is single. ...
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41
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General::munfl - Precision lost in LinearModelFit
I am new to mathematica so I am confused regarding the loss of precision in LinearModelFit. In building a linear model with uora (1 or 2) and encodeSeverity (1,2 or 3)
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3
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258
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How to deal with too small numbers
When dealing with a code that produces too small numbers (in a complicated way) like
0.33691 4.015757066049965*10^-330
I get the following warning
General::munfl: ...
- 317
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52
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Solving a determinant to get non-zero roots in a heat transfer problem
I am trying to solve a mathematical model of a heat transfer problem.
As an intermediate step there is a characteristic equation in the form of a determinant, which needs to be solved for variable <...
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92
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How to change Machine Precision digits to meet the tolerances
I am trying to solve for Tcm and Mag by solving nonlinear equations using FindRoot command using following code:
...
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0
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46
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Are pixels machine numbers? [closed]
Mathematica allows one to work with the information that is behind a photo. For example, the command ImageData generates a list containing the “pixels” (which will it be a number from $0$ to $1$ if no ...
- 141
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71
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Problem with the Rank of a matrix after a FindRoot
I am solving a boundary problem defined by a set of four-component vectorial functions. Without going into many details, I have two functions on the left and two on the right of an interface. The ...
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2
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102
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How to increase the value of MinMachineNumber to avoid overflow error?
I have a complicated function called f2[re]
...
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101
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How to copy and paste numbers with "`" mark and use them in calculations, without using N or setting precision every time
Suppose we have run a calculation and get a number like
2.758952615889003`
If we then copy-paste this number and do a calculation like
...
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2
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0
answers
115
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Generalizing technique to handle General::munfl error?
In contrast to earlier versions of Mathematica, in versions 11.3 and later Mathematica no longer switches to arbitrary precision when it detects a MachineNumber underflow. While this behavior is ...
- 550
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1
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92
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Too small to represent and Chop in inaccessible algorithm
Overview
I want to apply a specified Chop function to every step in an function call in Mathematica (in my case LegendreP), ...
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28
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Different sensitivies from LinearSolve and Eigenvalues. How to conciliate them?
I use the following functions to receive a matrix, and make it symmetric positive definite:
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General:: Exp[-717.401] is too small to represent as a normalized machine number; precision may be lost
I am solving pde.
For the post processing bvp, there is solution given in output which is the solution from mathematica version 10.0.1.
Output from above in mathematica 10.0.1 is,
But when the similar ...
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1
answer
57
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Avoid MachinePrecision numbers in Message
Can I change the output of Message to not show MachinePrecision numbers? E.g.
...
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