Questions tagged [data-analysis]

Data Analysis is the process of evaluating data using analytical and logical reasoning to examine each component of the data provided.

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What are the Exact Rules for Significant Figures, Precision, and Uncertainty?

In the physical sciences (which are physics, chemistry, astronomy, materials science, etc.), we learned that the uncertainty is +/- the smallest unit (which is 1) of the last significant figure if the ...
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Computing the overlapping area of curves

I have a set of datapoints that correspond to 5 curves. Sample dataset and MATLAB inputs: ...
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Fitting gauss-hermite-parametrization to data?

I want to fit this data. I have the following model functions. Classic gaussian: def gauss_model(x, mu, sigma): return np.exp(-0.5*((x-mu)/sigma)**2) And ...
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Bounds condition for IFT to obtain a $1/f$ time-series

I am coding a function to obtain a randomized time-series from a given $\frac{1}{f}$ law. The randomization is obtained by introducing a random phase in the function. I experience a problem in the ...
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Why do problems arise in FFT for smaller value of df in Python?

...
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Parameter explained by many distributions

If we had, for example, labeled data, where for each entry (label) we have several data distributions associated to it, how can I get something meaningful from them? Is this a solvable problem? Is ...
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I need help developing a process to map many individual records (from a database) into larger groups

There are many rows of data in a database table, each of which contains many columns. ID (numeric - 12345, 12378, etc) Name 1 - AAA,BBB,CCC Name 2 - dd, ee, ff Name 3 - Ggg, Hhh, Iii The objective ...
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Trouble Estimating Motor Parameters with Least Squares in MATLAB

Basically, I'm trying to use Least-Squares to estimate the parameters of a DC motor. My system can be modeled by the following matrix equation: $$\begin{bmatrix}V_{input}(t)\\0\end{bmatrix}=\begin{...
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How to extract connected components from persistence diagram?

From the given point cloud (Fig. 1), I use Scipy-TDA to extract persistence diagram (Fig. 2). What I'm interested in is to extract 3 circles. For example, I'd like to know 3 center points and labels ...
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Filtering out outliers in a vector field [closed]

I have a vector field that represents a incompressible fluid flow (ie. divergence-free, ideally) that contains a certain percentage of vectors that are completely incorrect, due to the procedure used ...
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Spline regularization

I am fitting some B-splines to data, but the data has a "gap" region where the spline is less constrained by the data. I want to devise a regularization scheme to help prevent the spline from ...
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Eigenfaces Algorithm

This might be a silly quesntion but recently I've been trying to program the eigenface algorithm using PCA, so I arranged the face vectors vertically in a matrix X such as: X = [x1,x2,x3,...,xn]; In ...
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Best way of storing numerical data in a compact manner, while leaving it accessible for tools like GnuPlot?

My simulation, written in C++, generates a large amount (roughly ~500) of text files for each set of parameters I try to simulate, with four columns of ~5k double values in each file. Furthermore, to ...
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How to check experimental data against a theoretical curve? (Python)

I am trying to check the agreement of a dataset against a theoretical curve, specifically a bandstop filter in an RLC circuit. I have generated a function which describes the curve we expect from the ...
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Computing the structure factor from positions and radial distribution function [closed]

I'm currently analysing some spatial point patterns that come from some fluid dynamics simulations and I'm having some difficulty computing the structure factor, $S(\pmb{k})$, from both the positions ...
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How to improve the efficiency of periodicity detection for long time based lined and gapped datasets

Our data set has $10^4$ data points, but has a long baseline and many gaps. As the histogram shows, the horizontal-axis is time and most of the time, there are no data. The vertical-axis is data ...
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3 answers
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Clustering with points lying along different 3D planes

I have a bunch of data points in 3D that lie along a few planes. What would be the best approaches to estimate the normals of these planes? Edit: There are roughly equal number of points lying along ...
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Is there a better way to do run time analysis than this?

I currently have 2 different functions with options to vectorise them: acc_rej_sine(max_iter, algorithm=None) and ...
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3 votes
1 answer
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GPGPU/FPGA programming for Combinatorial Analysis

Recently, I have taken an interest in performing combinatorial analysis for the game of 21 (blackjack) and attempted to use my AMD APU to try and thread the program via the 4 cores on the chip. ...
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Converting ROOT Tree to HDF5

I have a TTree in ROOT with 1000 events and 15 variables associated to each of them. I would like to convert this in its entirety to an hdf5 dataset. How do I organise my data in HDF5 Groups such that ...
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Which statistical method should I use for comparing machine run-time of two algorithms?

I am comparing the run-time of two algorithm by solving different instance of the problems. Sample of my data: ...
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Identifying the time window at which a meteorological factor influences tree growth the most

This is a problem I am encountering in a research project. I have thought of a naive approach to solve it which relies on many assumptions, is not guaranteed to work, and would be tedious and ...
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Validating a Markov chain and Bagging to find overall model

let´s say I estimated a Markov chain by splitting my data into traning and test data, and estimating the transition matrix for the traning data yields $$ P= \begin{bmatrix} p11 & p12 &...
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How much in depth should I cover Python? [closed]

I'm an undergrad who's studying electronics and fields like data sciences and mostly computing seem most interesting to me but have in-depth knowledge in neither. I learnt basic python last winter ...
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Implementing Frechet Distance on pandas data frame [duplicate]

I am working on a trajectory analysis project using python and its data science related libraries. I am planning to implement Frechet Distance algorithm for trajectory analysis, each trajectory has ...
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Python implementation for Frechet Distance

I am working on a trajectory analysis project using python and its data science related libraries. I am planning to implement Frechet Distance algorithm for trajectory analysis, each trajectory has ...
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Use custom defined metric(not matrix) in Javaplex

I'm about to get started trying to use Javaplex for the first time for some application in topological data analysis (TDA) and I want to use a custom defined metric. From looking over the documents, I ...
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What is the difference between Computational Science and Data Science? [closed]

Background: My PhD was in 'Computational Science'. My dissertation was on the analysis of X-Ray Diffraction Data and analysis of thermally perturbed nuclei in the overall dynamic analysis of the ...
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How are the outcomes that generated from different predictive models combined to get more accurate predictions?

The simple average is commonly used to combine the predictions out of different predictive models. Apart form the simple average, what are the other methods that can be used for combining the ...
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1 answer
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FFT (Numerical Recipes in FORTRAN 77)

I am trying to use the subroutine twofft which in turn uses subroutine four1 in the book(Numerical Recipes in Fortran) to ...
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6 votes
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Is resampling more accurate than block average for statistical analysis of data?

I'm working in laboratories where molecular dynamics data are almost always analysed usign block average as stated in the famous Allen and Tildesley book. We divide the datas in blocks of size $M$ on ...
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3 votes
1 answer
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Similarity of two CSV files (or more?)

A CSV file is characterized by a header, describing the n datarows to come. The header is a text string separated by a separator. A CSV header might look like (C1) ...
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library for arithmetic operations on unstructured xyz

I've got several sets of xyz-data where x,y are coordinates and z is a 'value'. I want to be able to do simple arithmetic operations on these data. The x,y locations are not necessarily the same in ...
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what is the best theory/model to use for prediction in multivariate data?

I use software for pollutant propagation on rivers that takes as input a set of parameters ($p_1,p_2,\ldots,p_n$) and creates an output file which is basically a matrix where on each row the ...
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1 vote
1 answer
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Finite difference for Lighthill source term

I have experimental data containing horizontal and vertical components of speed and I need to evaluate this: $$ \frac{\partial^2}{\partial x_i \partial x_j}\left(v_iv_j\right) $$ Denoting $U$ as ...
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4 votes
1 answer
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Is there a relationship between the covariance matrix and the partial derivative?

Suppose that there are $N$ pieces of data, each of which contains $M$ parameter values such that $N >> M$. If we put this information into matrix form ($N$ rows, $M$ columns) and then compute ...
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3 votes
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similarity/distance measurement between two ranked sequence

Is there an efficient way to measure similarity/distance between two sequences of ranked numbers/letters. The two sequences are of different length, and only have some elements in common? For example,...
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Manipulating/Extracting Data and Developing Methods - Language Choice [closed]

As a general programming enthusiast and aspiring Bioinformatician student I have an intermediate understanding of computing (languages) as well as Java, and to a lesser extent C++. Having knowledge in ...
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5 votes
1 answer
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Iterative Cunnigham correction in Millikans oil-drop experiment

I tried to write an analysis program in python for the Millikan experiment based on a paper from Jones "The Millikan oil‐drop experiment: Making it worthwhile" However, I cannot reproduce the ...
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Power series regression linear fit in VBA excel

I wrote a program that calculates the best fit in VBA excel for the following model $$ y_k=c_1x_k+c_0+c_{-1}(x_k)^{-1} $$ solving for the best fit parameters $c_1$, $c_0$, and $c_{-1}$. However I ...
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2 votes
1 answer
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Simple Path to Route Algorithm

I'm currently conducting research into subway paths, but stand in front of a problem, with no programming knowledge and an extremely short time-limit. Probably the question I am asking is trivial, ...
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1 answer
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Can Box-Cox transformation be applied for data of this form?

I have data of the form: X Y 3.53 0 4.93 50 5.53 60 6.21 70 7.37 80 9.98 90 16.56 100 And I want to find out $n$ so that this can be ...
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Gonzalez algorithm

I'm getting confused about implementing the Gonzalez algorithm for k-center clustering. The algorithm is : let $S$ be a data set Choose $z_1 \in S$ arbitrarily. Number $z$ is center. (In general ...
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2 answers
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What is "SOLVER" in R and Statistics/Analytics?

I tried to research what exactly is a SOLVER only to find a not clear-cut simple answer. My doubts still remain after going through several sites full of discussions about it. I need to clarify as to ...
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5 votes
2 answers
321 views

Dimensionality reduction of the domain of f(x)

I'm wondering if there is something analogous to a PCA for data sets where there is a dependent variable. (Though I am interested in any method of dimensionality reduction, PCA is just an example.) ...
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3 votes
1 answer
159 views

Monte Carlo Simulation - Random Number Motivation

For Monte Carlo simulations, or any other numerical methods that rely heavily on the quality of the pseudo-random numbers generated (i.e even/desired distribution on a certain domain) for that matter, ...
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8 votes
4 answers
703 views

Should I use a database to handle large amounts of results?

Background: I am currently running a large amount parameter variation experiments. They are being run in Python 2.6+, using numpy. These experiments are going to take about 2 weeks to run. Roughly I ...
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1 vote
0 answers
150 views

SciDB vs OLAP cube [closed]

I am working on good retrieval mechanism for big data systems. I am of view that multidimensional structures could be of great use for aggregations and querying . Multidimensional structures as ...
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2 votes
2 answers
362 views

Extracting time scales information from empirical cumulative distribution function

I have a stochastic process (a Markov chain actually) that has two absorbing states. I am using a difference equation to calculate the first passage time to either of the absorbing states. There are ...
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1 answer
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Finding maximum value in huge dataset

I am working on a project involving some pattern recognition. For this I need to find the maximum value in a huge multidimensional dataset. For example I have a discrete 5-dimensional space containing ...
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