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0
votes
1answer
42 views

How to show right count of decimal number in mathematica 10

I have some random number x. It can be 222.1245646 or 3.141562652. How should I show this number to 5 decimal numbers ? I cant use this: N[x, 5] because it shows 5 ...
1
vote
2answers
64 views

ListPlot3D with small (but acceptable) precision

Consider the following minimal example: ...
1
vote
1answer
47 views

Increase Precision in Numerical Integration

I need to generate a table of Chebyshev expansion coefficients of trigonometric functions (in this case Cos[2 Pi t] to very high accuracy. Code is: ...
0
votes
0answers
28 views

How to set all the numerical values as double

Is it possible to set the accuracy of every numerical value and the result of every computation to double like in Matlab? I want Mathematica to use just 3 or 4 ...
0
votes
3answers
62 views

High-Precision NSolve

I need to calculate the intersection of two curves f1[x_] := ((Zl ρ ) Exp[-x]) f2[x_] := (α k e^2 /x^2) Where ...
2
votes
1answer
48 views

Working precision and pure functions in FindMinimum

I have this function: fun = (# - 5.0)^2.0 & Then, I want to find the minimum: ...
0
votes
1answer
62 views

How to work with decimals (e.g. 0.95) instead of fractions (95/100) and get the same result

In my code I have a function, F, that depends on several parameters, say a,b,c: F(a,b,c). I need to give a grid of values to a,b and c to obtain the value of F. My grid of values are decimal ...
0
votes
0answers
23 views

the default option of NDSolve

How should I find out what the default value of Accuracy and Precision is in the NDSolve? I have a pde that when I asked it to solve for me the equation with a special Accuracy and precision it gave ...
2
votes
2answers
94 views

Increase precision for a entire notebook

I am quite a newbie and it is taking me so much time to understand what I need to do to achieve something really simple and I still haven't found it. I run a dynamic model of a metabolic pathway in ...
2
votes
1answer
56 views

Range and decimal digits [duplicate]

When I set Plot[Sin[x], {x, -2, -1}, Frame -> True, Axes -> False, FrameTicks -> {{Automatic, Automatic}, {Range[-2, -1, 0.2], Automatic}}] I ...
0
votes
0answers
35 views

Numerical Error with Matrix operations

A is a 3x3 matrix, b is a 3x1 vector. I try to convert [A|b], a 3x4 matrix, to [I|0]. So the formula is right multiple ...
6
votes
2answers
193 views

A problem about fixed point iteration theory

Description Recently, I have been learning a couse called "Numerical Analysis". The fixed point iteration theory was introducted to solve the ...
2
votes
4answers
124 views

Precision problem with numerical solution of a differential equation

I want solve $$ 2\sqrt{|\gamma|}x = \int_{1}^{t} dy \sqrt{\frac{1+2|\gamma_2|y}{y^2(1-y)}} $$ where $0<t\leq $1. I'm using a for cycle to evaluate t, calculate the integral and the assign the $x$. ...
8
votes
2answers
176 views

Error computing sum of sum of digits

I've defined a function that computes the sum of the base-b digits of n: DigitSum[n_, b_] := Total[IntegerDigits[n, b]] Then I defined a function that computes ...
1
vote
1answer
105 views

NDSolve fails for certain choices of parameters and solve range

I'm trying to solve a pair of coupled ODEs with NDSolve. I know roughly what the solution should look like (both should give periodic functions, pi/2 out of phase, the amplitude of which damp towards ...
4
votes
2answers
56 views

numerical precision in output file

I want to write the numerical results of a computation to a file which is to be read in Fortran. The data looks like: ...
1
vote
1answer
75 views

How to suppress a warning message

If I change $MinPrecision before running ListPlot[{{1, 2}}], there will be a warning in Mathematica 10. But there is no warning ...
4
votes
3answers
145 views

Importing High Precision (22 digits) data from a file

I want to import list from a file and I am using ReadList but my data is in format like this 8.2457409790900004e+08 but it i being imported like $8.24574*10^8$. Is ...
4
votes
2answers
184 views

Why does N[Re@f] give complex result?

Consider this code: ...
5
votes
1answer
118 views

Numerical error in Mathieu functions

Consider the MathieuCharacteristicA function, which is a piecewise function according to the documentation. The discontinuity happens at integer number. ...
3
votes
0answers
89 views

Precision problem while evaluating RegionMember or Element in V10

I'll try to give you a background on where the problem occured. The problem itself is defined near the end of the post. I'm running a sort of a simulation of a particle in a box. I finally got my ...
0
votes
0answers
53 views

Precision of sliders in WebMathemtica

I have been developing a manipulate plot to put on the web. One of my parameters varies over a small interval, {{D32, 2.38*10^-3, "D32"}, 0.001227, 0.0049108}. This ...
1
vote
1answer
55 views

How to make a discretized NMinimize more precise

I am using Mathematica for physics research and I want to minimize a Hamiltonian equation with respect to two variables (I have also discretized the problem). I have a single constraint. When I plot ...
1
vote
2answers
78 views

SetPrecision — different values subtracted from unity gives same value

How are my results possible? CODE: SetPrecision[FibersFailedNew, 40] 3.612171938234261799295174910010284760488*10^-16 ...
1
vote
1answer
104 views
1
vote
1answer
63 views

Inaccuracy of Piecewise function? [duplicate]

I have the following issue and can't find a solution so far. ...
6
votes
3answers
210 views
0
votes
0answers
69 views

Meaning of backtick in conjunction with units [duplicate]

In this fragment from an equation solution the backtick is used twice: ...
2
votes
2answers
129 views

NIntegrate - WorkingPrecision

I am trying to NIntegrate this expression. It is very close to zero, and so gives all possible types of errors. More precisely, ...
0
votes
1answer
172 views

How to get more accurate orthonormal eigenvectors?

I have a matrix M with real entries in MachinePrecision. I compute its eigenvectors and construct matrix ...
0
votes
0answers
22 views

Ignore $MinPrecision when using Print

I have a function that contains a For loop and sometimes takes several hours to run. It's important that I keep a high precision, and I insert ...
0
votes
0answers
28 views

How to get precision for a small calculation? [duplicate]

For pc1 and pc2 this gives the answer to only four decimal places. How can I get better precision? ...
1
vote
1answer
165 views

Numerical Instability?

Current Status Please skip ahead to Update 2: the key questions are now: 1/ Why does Mma generally fail to find the minimum for a well behaved function when the function does not have infinite ...
1
vote
1answer
54 views

ReadList error with negative very small numbers

When I try to import data with ReadList from a file containing very small numbers (~10^-318), positive data is handled well, ...
4
votes
3answers
180 views

Increasing the precision of a calculation

Clearly I have misunderstood how to do this: I seem unable to understand how to get more digits out of a calculation and I can't see why - the following piece of code illustrates the issue. ...
0
votes
1answer
108 views

How can I obtain more significant digits? [closed]

I type f1[x_] := 12 x^5 - 975 x^4 + 28000 x^3 - 345000 x^2 + 1800000 x N[f1[15.5], 15] and obtain 3.74112*10^6 BUT It´s not true!!! the result is larger than ...
1
vote
0answers
32 views

Frontend displays wrong number digits [duplicate]

How do I change the default precision in Mathematica? Somehow the setting has been changed to 1 digit, so if I type Timing[...] I get {1., ...} which is ...
1
vote
1answer
277 views

Plot periodic function from Dirac delta function [duplicate]

Sorry for my bad english. I need to plot periodic function from dirac delta: δT(t)=∑δ(t–n*T), where T - is a constant, and n=-20..20 And after them, plot new function fd=f(t)*δT(t) - discrete signal ...
5
votes
1answer
55 views

Mysterious behavior of Precision for complex arrays

Mysterious behavior of Precision: {{1.0+I*0.0},{0.0+I*0.0}} // SetPrecision[#,30]& // Precision // Print; ...
4
votes
1answer
87 views

Issues with $MachineEpsilon

I'm attempting to add $MachineEpsilon to numbers I am pulling from the domains of 3 interpolating functions. I pulled 3 numbers, and for one of these numbers adding ...
3
votes
0answers
87 views

Tools for Stability/Automatic Error Analysis in Mathematica

I have a longer analytic expression in several variables containing special functions and others. Does Mathematica bring tools - or are there any packages - to examine the stability when I evaluate ...
1
vote
1answer
139 views

ListPlot with high precision

I have a list of numbers, e.g. {{1.,0``27.698970004336022},{2.,0``27.698970004336015}} but usually much longer, suitable for ...
2
votes
0answers
111 views

how to calculate with just double floating point precision [duplicate]

I want to calculate with simple double floating point precision. ...
3
votes
4answers
163 views

AccountingForm w/o significant figures

Basically I want to build a chart like something I would do in Excel. It should look like this: Here is the formula I'm using and what I've done so far ...
5
votes
2answers
1k views

How to convert a string of number into real numbers without precision loss

I searched and did not find similar answers which can resolve the 'no precision loss' issue. A sample string is: ...
4
votes
1answer
648 views

How to set the working precision globally? $MinPrecision does not work

I want to increase the precision globally to 50 at least, but $MinPrecision does not work. ...
0
votes
1answer
88 views

Truncate a fractional value to particular number of bits?

If I have a fractional value, how can I truncate (not round) that to a certain number of bits, like 8? For example, for Pi 3.141569265359... the fractional part is 0.141569265359... ...
5
votes
1answer
447 views

ReadList can't read from file containing high-precision Reals

I want to read a file which contains seven columns of real numbers. Mathematica seems to have a problem with the high precision I need. My code: ...
2
votes
1answer
107 views

Why the EuclideanDistance of these 2 exact points generates the warning N::meprec?

The two points are: pts = {{1/4 (-1 - Sqrt[5]), Sqrt[5/8 - Sqrt[5]/8]}, {1/4 (-1 - Sqrt[5]), -Sqrt[5/8 - Sqrt[5]/8]}}; EuclideanDistance @@ pts ...