The data tag has no wiki summary.
2
votes
2answers
61 views
Importing LTSpice data into mathematica
I am working with LTSpice (Discret electrical circuit ( Spice) simulator). I would like to import LTSpice ouput data into mathematica for processing and plots.
An example of a file can be found here ...
1
vote
0answers
74 views
Performance in parameter estimation from ParametricNDSolve using varied initial conditions
I have 250 data points from a timecourse exeriment in a list, with columns specifying (1) time, (2-4) initial conditions, (5) absorbance reading. I want to fit 4 parameters (k1, k2, k3, k4) in a DAE ...
3
votes
1answer
63 views
Saving and Reading data across computers
I DumpSaved some data from my home laptop, uploaded it onto google drive and now I am trying to open it at my school computer but I am getting errors, even though the data is in the correct directory. ...
0
votes
1answer
47 views
How to work with Interpolated Functions? [closed]
I am just a beginner and struggeling with experimental data and further processing in Mathematica:
I first constructed a table from two columns (t20 and J20) in Excel:
...
1
vote
0answers
53 views
Significant platform-dependent efficiency when importing data?
I'm curious, as I understand that answer this way:
If you are using a Linux derivative or something like cygwin on
Windows, then this is an efficient solution for reading only the third
field ...
1
vote
2answers
101 views
Efficient Data Entry / Manipulation with Many Datasets
I currently have a simple task of graphing many different datasets (26 here, with many different instances where I'll need to do, say, 26 different ones from the same template). I'm trying to ...
2
votes
2answers
99 views
Importing several huge files with headers & footers
having here several files in ASCII format
http://ge.tt/91rv0Jf/v/0
I want to import, while removing headers and footers and then join the several lists.
...
12
votes
3answers
169 views
How to Import random elements of huge data files
I am calculating huge data files with an external program. I would like then to import the data into Mathematica for analysis. The files are 2 columns and up to many millions of rows.
So for ...
0
votes
1answer
48 views
Substituting Data from File
I have sets of Diff. Eq. that I'd like to solve symbolically, then substitute in numerical values for some of the symbols. I'd like to store the value for each symbol in a file, e.g., an excel ...
0
votes
0answers
38 views
tree of values representation
Main Question
Is there an efficient way to output a tree of values similar to the output of TreeForm?
Something like
...
1
vote
1answer
66 views
Table/Tree of values
My question:
Is there a way to create a tree of values?
Something like the output of the command TreeForm,
but with values in the nodes?
Why do I want this?
I'm trying to do a complete program to ...
8
votes
5answers
217 views
Determine the Number of Lines in a Text File
I have looked and looked but I do not see a simple efficient way to get MMA to return the number of lines in a text file?
I thought about reading the file until it returned the EOF marker, but that ...
0
votes
0answers
55 views
How to combine file data chronologically via reading numbers in a filename and put it in one list?
Say I have a bunch of files with nearly same filename, eg. data_timestep1, data_timestep2, ...
The data itself in one file is ({x1, y1, z1, absolute field value 1}, {x2, y2, z2, absolute field value ...
2
votes
0answers
50 views
How can I recover a graph from a graphical output in a notebook after resetting the kernel?
I have an old Mathematica notebook with an output for a graph structure $G$ I would like to recover. However, the routine for building up the graph is stochastic, so I can't simply rerun the code.
...
0
votes
2answers
101 views
Request help for reading text data files with headers and 2 sections
I just started with Mathematica.
I need it for many purposes, but the important one is to read a text data file and extract column values as variables.
I have successfully tested the tab delimited ...
1
vote
0answers
206 views
Doing local FFT on huge 3D vector data cell mesh and visualizing it spatially?
Simulation type:
I'm running a simulation with the OOMMF micromagnetics package
http://math.nist.gov/oommf/
where are magnet is represented by a mesh of 3 million cells, it gets excited by a ...
5
votes
3answers
188 views
Storing data in the Notebook in readable form
The common problem in my theretical work is a need to import some experimental data to work with. This means that my notebook depends on some external files which makes it difficult to share it with ...
12
votes
4answers
388 views
Plotting data points: Optimizing size and visuals
The following problem is one that may have showed up to you while plotting a large data collection. Suppose you have a data set of say 1 million points. ...
1
vote
1answer
78 views
Automating sequential import of data from web
I am trying to import data from multiple web pages hosted by a single online source. The data is posted by the source as one data set per web page for each week of the year. I would like to import the ...
1
vote
2answers
134 views
Running out of memory when filtering a large data set
My goal is to read list0.dat, filter the data with a function f, and then write the transformed data to ...
4
votes
1answer
424 views
Transform 3D data into 2D color map like Matlab's surf/imagesc
I have a bunch of 3D data (x, y coordinates and values) which is generated in Matlab and I need to render them in a 2D color map with certain axis ranges. Here are the Matlab code and the generated ...
3
votes
2answers
263 views
Check Google PageRank for a given URL
Does anyone know how to write a Mathematica function that returns the Google PageRank of a given URL?
I found a tutorial for achieving this in a bash script here, but I have no idea how to port this ...
3
votes
1answer
119 views
NonlinearModelFit returning nonsense for very simple data
In fitting the following data, if I first log transform the y-values and use LinearModelFit I get a set of parameters that fits the data:
...
2
votes
2answers
135 views
How can I control the number format of exported data?
I'm having issues while exporting a tables of numerical values to "*.dat" data files.
Here's the thing, sometimes when I export a table, I get more decimals on some random values. The problem is that ...
0
votes
2answers
189 views
Export plot data in Mathematica [duplicate]
How can I export data, which is plotted using something such as:
Plot[Γ[x]/(1.6*10^(-19)), {x, 0.1, 1.2}]
into a .txt file in Mathematica?
-2
votes
1answer
121 views
Non-regular grid data
I have issue with non-regulary spaced data. I have set of 3 numbers {x, y, z} in my list.
...
5
votes
1answer
121 views
WolframAlpha Selective SubPod Content
I am sending queries to Wolfram | Alpha from Mathematica V9 and and importing the results back into Mathematica, but I am running into a challenge in formatting the request. Specifically, I would like ...
3
votes
2answers
171 views
ListContourPlot interpolation screws up on concave set of data
I want to create ListContourPlots for sets of Data (from a physics simulation) given as Triplets {x, y, f(x, y)}. Certain parameter regions in the x-y-plane are ...
2
votes
1answer
196 views
Importing data sets from plain-text files and performing operations on them
I am working with a lot of daily weather files in the txt format. I need to calculate a daily quantity from each of them, e.g., daily light intensity, which ...
2
votes
1answer
143 views
Read and filter a text file without importing
I have a large text file of a million sections. Each section contains A lines of header and B lines of numeric data.
I want to read the first and last line of B from each section (to have a list of 2 ...
8
votes
3answers
348 views
Approximately Fit Data Without FindFit
I have some noisy data, and I'd like to analyze the derivative of the function the data approximately matches. Interpolation is normally great, but doesn't work ...
2
votes
1answer
86 views
Plot[] breaks behavior of custom data handling function - Recursion
I am working on a utility to analyze a set of data. I want to process the data with a sliding window, in such a way that there is an output associated with each sample of data.
To start, I have a ...
7
votes
3answers
312 views
How to integrate functions of linearly interpolated data?
At first, consider integration of pure InterpolatingFunction.
Importing some data (works in v.9, for earlier versions one can use this link to download zipped ...
1
vote
0answers
73 views
ReadList and multiple access of the same file
I have a file containing a large amount of data which can be processed independently. In order to process all data in a reasonable amount of time I distribute the jobs on three different machines. ...
6
votes
1answer
93 views
DataEncoding in HDF5 format
I would like to export data in HDF5 format with Mathematica 9.
The Mathematica manual about Import and Export of this format can be readen here.
As I'm dealing with large arrays, export often lead to ...
0
votes
3answers
120 views
How to export a header before the data in the result file?
I would like to export a phrase to my result data as a heading.
I'm exporting the data correctly with
Export["file.dat", table].
But I'm doing several ...
2
votes
3answers
132 views
Making data persistent, as in xmgrace
I've been using xmgrace for quite a long time as my favorite solution for scientific data manipulation and plotting. These data often come from home-made fortran programs, in the form of, e.g., a ...
1
vote
1answer
184 views
Optimizing the fitting of Ordinary Differential Equation(NDsolve) involving interpolation functions
I am a newbie to this forum. I am trying to use NDsolve to solve some ODEs involving the interpolation function. Then, I will compare the fitted curve and data to determine the ODE coefficients.
...
5
votes
1answer
141 views
LinearModelFit with millions of rows
I'd like to do a simple regression with millions of rows of (x,y) data. It seems to be too long for Mathematica. Is there a way to speed it up? It shouldn't be that hard to do, I am not sure what ...
3
votes
3answers
244 views
How do I make a frequency heatmap?
I have an array of data that has repeats in it. I want to generate a heatmap depending on how much repetition each point has, as in how many times it is repeated.
4
votes
0answers
122 views
How do I view the value of a variable in its raw, binary form, as stored in memory? [closed]
If I have a variable, how do I turn it into a list of bytes or a string containing its value as it's stored internally? To better illustrate what I mean, what I want to do could be done in C with ...
0
votes
1answer
168 views
importing and manipulating data file
I have a large text file containing numeric data of 1000 groups each of 200 lines. The lines are unsorted. There is a 9 line header at the beginning of each group, i.e., 209 ⨉ 1000 lines altogether.
...
1
vote
0answers
146 views
Data wrangling messy data
This is an offshoot from my previous question about dealing with large datasets in Mathematica. I think it might provide more value to more people as a separate question.
I'd like to know how people ...
8
votes
2answers
471 views
How do you deal with very large datasets in Mathematica?
This question is in two related parts. The first is about dataset size, the second data wrangling.
Part 1:
I've built a naive Bayesian classifier on Mathematica. It uses ...
0
votes
0answers
70 views
How to map over non-Null values in a list [duplicate]
Possible Duplicate:
Selectively Mapping over elements in a List
I have a list of distributions and a list of samples. I'm trying to calculate probabilities of some record being within one ...
3
votes
0answers
79 views
External file Sub Matrix Import
Is there a Built-In Mathematica Function to extract a
Sub matrix from a huge external file?
Functions getting pieces of internal nested Lists, (arrays) are in place.
Example:
...
3
votes
2answers
229 views
How do I plot the derivative of a set of experimental points?
I have a set of points like this: P = {{$x_1$,$y_1$},{$x_2$,$y_2$},...,{$x_n$,$y_n$}}. I want to plot them and also plot the derivative of that graph. How can I do this with Mathematica? Is there a ...
7
votes
3answers
301 views
Analytically finding critical values in a hysteresis curve made with ListPlot
Let me start with a super basic explanation of what I'm trying to do, and I will follow with a more detailed discussion afterwards.
From data in the form shown below (a ...
8
votes
1answer
260 views
Dealing with large files
I have a *.dat file in which the contents are basically one giant list:
{1,2,3,4} {5,6,7,8} {9,10,11,12}
and so on. I'd like to read in the first 500 members { ...
27
votes
4answers
557 views
Filtering beat-to-beat heart rate data
From an experiment, I have a dataset of beat-to-beat heart rate data: a list of the time between each heart beat in [ms].
The data is measured using an infrared optic sensor at the finger tip. The ...
