text stringlengths 49 10.4k | source dict |
|---|---|
c++, beginner, linked-list, reinventing-the-wheel, c++17
Node* new_node = create_node(next_node, previous_node, std::forward<Args>(args)...);
previous_node->next = new_node;
next_node->prev = new_node;
++current_size;
return iterator(new_node);
}
template<typename T>
temp... | {
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"openwebmath_score": null,
"tags": "c++, beginner, linked-list, reinventing-the-wheel, c++17",
"url": null
} |
quantum-mechanics, potential-energy, measurement-problem, quantum-tunneling
So there is a way to do this in the classical way, using evanescent wave coupling.
Especially in optics, evanescent-wave coupling refers to the coupling between two waves due to physical overlap of what would otherwise be described as the eva... | {
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"tags": "quantum-mechanics, potential-energy, measurement-problem, quantum-tunneling",
"u... |
classical-mechanics, solid-state-physics, frequency, coupled-oscillators, normal-modes
$$
as expected.
If we want to emphasize how the fixed total energy E sloshes back and forth between (real) kinetic energy and (real) potential energy, we could write:
$$
E_k(t) = E/2 -\frac{k}{4}\Re({\hat u^2e^{i2\omega t}})
$$
$$
... | {
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"id": 90010,
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"openwebmath_score": null,
"tags": "classical-mechanics, solid-state-physics, frequency, coupled-oscillators, normal-m... |
dna-sequencing
or
genewise -pep -pretty -gff -cdna prot.fa dna.fa > out.txt
In my experience exonerate is (much) faster but genewise is a little more accurate. I usually use exonerate if I am dealing with a whole genome and genewise if I only have a few kilobases of sequence. Both are very good and both will be able... | {
"domain": "biology.stackexchange",
"id": 1664,
"lm_label": null,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "dna-sequencing",
"url": null
} |
electromagnetism, special-relativity, magnetic-fields, inertial-frames
Title: Why Moving charge and a current carrying wire creates magnetic fields? My question is why exactly the moving charge or a current carrying wire creates magnetic field around themselves?
Some of them call it as a consequence of special theory ... | {
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"tags": "electromagnetism, special-relativity, magnetic-fields, inertial-frames",
"url": ... |
classical-mechanics, differential-geometry
Title: Why does adding kinematical conditions between the coordinates prevent the Riemannian line element to "preserve the Euclidean structure"? I was reading Kinetic Energy and Riemannian Geometry in The Variational Principles of Mechanics by Cornelius Lanczos; here is the c... | {
"domain": "physics.stackexchange",
"id": 33727,
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"openwebmath_score": null,
"tags": "classical-mechanics, differential-geometry",
"url": null
} |
regression, correlation
Title: Chose among highly correlated variables I am working on a Kaggle dataset and I am trying to build a predictive model for the "Chance of Admit" (dependent variable) of students to the university of their interest.
Below you can find the correlation among all (independent and dependent) v... | {
"domain": "datascience.stackexchange",
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"tags": "regression, correlation",
"url": null
} |
### Method 2 - Method 1 Modified
There's a flaw in method one in the case where the points are collinear and lie on a vertical line, i.e., where there are repeated x values. Then the denominator we calculate will have the differences of two x values that are the same, resulting in division by 0 and a non-finite slope.... | {
"domain": "mathworks.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9825575152637946,
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"lm_q2_score": 0.8333246035907933,
"openwebmath_perplexity": 2463.922503319065,
"openwebmath_score": 0.564433217048645,
"tags": n... |
Sample data occurs whenever a subset of a group is selected, some characteristic observed in that smaller group, and the results are imputed to the entire group. Summary data of a sample (such as averages) are called statistics. Sampling is done because of efficiency and cost, and as it turns out, if the process is car... | {
"domain": "milefoot.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.964321452198369,
"lm_q1q2_score": 0.805674701737617,
"lm_q2_score": 0.8354835411997897,
"openwebmath_perplexity": 686.942925545672,
"openwebmath_score": 0.5609696507453918,
"tags": null... |
performance, sql, mysql, search
Address Table
`address_id` int(11) NOT NULL AUTO_INCREMENT,
`address_full` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`address_1` varchar(255) COLLATE utf8_unicode_ci NOT NULL COMMENT 'address name or number',
`address_2` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`address_3` va... | {
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"id": 7711,
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"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "performance, sql, mysql, search",
"url": null
} |
statistical-mechanics, entropy
Title: Equality of the formulae $S=k_B\ln\Omega(\bar E)$ and $S=-k_B \sum_i p_i\ln p_i$ for the canonical ensemble Reif's book on Statistical Physics is one of the most prescribed books in the subject. For the canonical ensemble, he derives that the formula for entropy is $$S_{\rm can}=k... | {
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"id": 66555,
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"tags": "statistical-mechanics, entropy",
"url": null
} |
vba, excel
'/======================================================================================================================================================
'/ Author: Zak Armstrong
'/ Email: zak.armstrong@company.co.uk
'/ Date: 12/August/2015
'/ Version: 1.0
'/
'/ Is Called By: Generate_Adviser_Su... | {
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"id": 15321,
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"openwebmath_score": null,
"tags": "vba, excel",
"url": null
} |
waves, fourier-transform, oscillators, string
What I've not conceived is
So, what is $f(z)?$ Crawford told all the story here solely of $f(z).$ What is it actually? I thought $\psi(z,t)$ is the wavefunction- the general state of the string which is just the superpositions of infinite modes as in Eq.$(38);$ where did ... | {
"domain": "physics.stackexchange",
"id": 25905,
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"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "waves, fourier-transform, oscillators, string",
"url": null
} |
molecular-structure, metal, crystal-structure, crystallography
This seems potentially relevant: Chapter Six - Computer modeling of Zircon (ZrSiO4)—Coffinite (USiO4) solid solutions and lead incorporation: Geological implications
The structure of zircon, ZrSiO4 is modeled using interatomic potentials. The uranium end-... | {
"domain": "chemistry.stackexchange",
"id": 17111,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "molecular-structure, metal, crystal-structure, crystallography",
"url": null
} |
ros, rviz, gui, qt
Title: rviz qt creator gui
Hi all
I have a question.
I would like to develop a GUI. I want this GUI to interact with a robot running the navigation stack, further I would like to insert this GUI in RVIZ so I can have just a single GUI to deal with.
Can some body tell me the best way to tackle this ... | {
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"id": 15312,
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"tags": "ros, rviz, gui, qt",
"url": null
} |
python, performance
def stop(self):
"""Shutdown the watcher for all paths"""
for path, observer in self.observers.items():
self.paths.remove(path)
observer.stop()
def watch(self, path):
"""Starts the filesystem watcher on the specified path"""
if normalize(p... | {
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "python, performance",
"url": null
} |
optimization, recursion, scala, iterator
Title: Is this a correct recursive Scala iterator creation? I am diving into Scala (using 2.10) headfirst and am trying out a simple task of taking bulk data and then doing something with that stream. The first part is generating that stream. I have seem to be able to cobble to... | {
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"tags": "optimization, recursion, scala, iterator",
"url": null
} |
reachability is the number! Conclude that the vertices and edges in the above graph, all the vertices are reachable one... Can specify the directions of the edges it can contain edges that a directed graph edge is! Integer n which represents the number of edges that the graph has one less edge without removing any.! A ... | {
"domain": "com.pl",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9559813501370537,
"lm_q1q2_score": 0.8047696150458991,
"lm_q2_score": 0.8418256432832333,
"openwebmath_perplexity": 336.6122501623908,
"openwebmath_score": 0.4763352572917938,
"tags": null,
... |
javascript, php, jquery, html5, email
<body>
<header>
<nav>
<ul>
<li>Menu Item</li>
</ul>
</nav>
</header>
<section>
<h1>Contact Us</h1>
<p>Please answer a couple of short questions</p>
<p id="error-msg"></p>
<form i... | {
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"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "javascript, php, jquery, html5, email",
"url": null
} |
python, beginner, project-euler
if grid[(rsub*20)+3+r]* grid[((rsub+1)*20)+2+r]* grid[((rsub+2)*20)+1+r]* grid[((rsub+3)*20)+r] > largest[3]:
largest[3] = grid[(rsub*20)+3+r]* grid[((rsub+1)*20)+2+r]* grid[((rsub+2)*20)+1+r]* grid[((rsub+3)*20)+r]
print max(largest)
Even though I got the answer right, I... | {
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"openwebmath_score": null,
"tags": "python, beginner, project-euler",
"url": null
} |
# Find unit normal vector to the surface $z=x^4y+xy^2$ at the point $(1,1,2)$
I've been trying to solve this question:
Find a unit vector with positive $z$ component which is normal to the surface $z=x^4y+xy^2$ at the point $(1,1,2)$ on the surface.
My working:
Let $z=f(x,y) = x^4 y + xy^2$,
$$\begin{split}\frac{\... | {
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"lm_q1_score": 0.977022627413796,
"lm_q1q2_score": 0.8032973845336204,
"lm_q2_score": 0.8221891305219504,
"openwebmath_perplexity": 232.4977411596802,
"openwebmath_score": 0.8865489959716797,
"tags... |
error-correction, stim
Title: Stim detector error model to syndrome graph How can I convert a Stim detector error model into a networkx/rustworkx weighted graph representing the equivalent syndrome graph?
I want it to test a possible method to introduce erasures in the high erasure rate regime, where the method descri... | {
"domain": "quantumcomputing.stackexchange",
"id": 4512,
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"lm_name": null,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "error-correction, stim",
"url": null
} |
# Victoria Solving Recurrence Relations Using Generating Functions Pdf
## Solving Recurrences Calvin College
### Solving Recurrence Relations Oscar Levin PhD
1 Solving recurrences Stanford University. We can use generating functions to derive the closed-form solution. The basic procedure: 1. Derive a generating func... | {
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"lm_q1_score": 0.9838471637570105,
"lm_q1q2_score": 0.8342706664773966,
"lm_q2_score": 0.8479677506936878,
"openwebmath_perplexity": 616.8304921082495,
"openwebmath_score": 0.6817836165428162,
"tags... |
# simplify the following expression by writing it as a single summation
The question asks to simplify the following expression by writing it as a single summation (the second sigma in the expression should have upper limit of n+2):
$$3\sum_{i=2}^n (2i^2-i) - \sum_{j=4}^n (3j^2+1)$$
Im having trouble figuring this on... | {
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"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9664104953173167,
"lm_q1q2_score": 0.8032253584971583,
"lm_q2_score": 0.8311430415844384,
"openwebmath_perplexity": 273.3031144083817,
"openwebmath_score": 0.9575137495994568,
"tag... |
cosmology, space-expansion, dark-matter
Title: What does it mean for CDM to "decouple from baryons" I am currently working on my Final Year Project as an undergraduate, mostly intended to be a review of $\Lambda$CDM model and some of its modern challenges.
When talking about Cold Dark Matter I stated it must be cold i... | {
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"id": 77604,
"lm_label": null,
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"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "cosmology, space-expansion, dark-matter",
"url": null
} |
javascript, algorithm, array
Q1
But I can see it looking ugly and not really optimized (code duplicating)
Ugly is somewhat subjective (2 spaced indents are ugly in my book), and sometimes unavoidable, as long as it is readable then looks don't matter.
Code duplication is not a code optimization problem, in fact it i... | {
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "javascript, algorithm, array",
"url": null
} |
python, game, recursion, sudoku, community-challenge
def _to_set(self, cells, r=None, c=None):
a = filter(None, [self.array[r][c] for r, c in cells])
s = set(a)
if len(a) != len(s):
raise InconsistentBoardException(r, c)
return s
def row_excl(self, r):
"""
... | {
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"id": 5341,
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"openwebmath_score": null,
"tags": "python, game, recursion, sudoku, community-challenge",
"url": null
} |
general-relativity, differential-geometry, tensor-calculus
which is the origin of the mysterious extra term.
$^\dagger$Note that this is not abstract index notation - the indices in this final expression take numerical values, and the quantities being labeled are the components of tensors (and the Christoffel symbols)... | {
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"id": 90166,
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"openwebmath_perplexity": null,
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"tags": "general-relativity, differential-geometry, tensor-calculus",
"url": null
} |
It's tempting to say the following: $$(C_4 \times C_2)/(C_2 \times \{0\}) \cong C_4/C_2 \times C_2 /\{0\}$$ and $$(C_4 \times C_2)/(\{0\} \times C_2) \cong C_4/\{0\} \times C_2/C_2 \text.$$ But does this trick actually work in general? In other words, is the proposition below true?
Let $$G$$ be an external direct prod... | {
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"id": null,
"lm_label": "1. Yes\n2. Yes",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9850429151632047,
"lm_q1q2_score": 0.8332896025937157,
"lm_q2_score": 0.8459424353665381,
"openwebmath_perplexity": 102.01982029300129,
"openwebmath_score": 0.9774518013000488,
"ta... |
java, hibernate, jpa
/**
* getter for password.
*
* @return the password of the user
*/
@Override
public String getPassword() {
return "";
}
/**
* getter for phone number.
*
* @return the phone number of the user
*/
@Override
public String getPho... | {
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"id": 10242,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "java, hibernate, jpa",
"url": null
} |
matlab, fft, eeg, segmentation, signal-power
Title: How to segment frequency bands after FFT and calculate power? I have been working with EEG signal. I have raw EEG data for a 2-second (i.e. $t=2$) duration. My objectives are:
Transforming these raw data from time domain to frequency domain.
Segmentation into two f... | {
"domain": "dsp.stackexchange",
"id": 4546,
"lm_label": null,
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"lm_q1_score": null,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "matlab, fft, eeg, segmentation, signal-power",
"url": null
} |
the rate convergence... Two more criteria in Section 5.1 licensors or contributors... John T. Saccoman, in Elementary linear.... M is selected, then D is determined calculation results to, we associate with each arrows directed the... Prove Theorem 3 of Section 3.4 ) stationary distributions two eigenvectors of a matri... | {
"domain": "aobindia.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.990440598395557,
"lm_q1q2_score": 0.812055652780913,
"lm_q2_score": 0.8198933425148213,
"openwebmath_perplexity": 606.9326889357603,
"openwebmath_score": 0.8793156147003174,
"tags": nul... |
statistical-mechanics, fermions, bosons
Title: How does one integrate the Fermi-Dirac distribution using the zeta function? I've seen in my physics book that:
$$n=\frac{g}{2\pi}\int_0^\infty\frac{E^2dE}{e^{E/T}\pm1}$$
Regarding the number density of a relativistic gas of either bosons ($-1$) or fermions ($+1$). The so... | {
"domain": "physics.stackexchange",
"id": 77685,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "statistical-mechanics, fermions, bosons",
"url": null
} |
newtonian-mechanics, relative-motion
First, the ball did indeed fly through the driver’s window, but instead of getting stuck inside the car as it would have if it were not for the driver rolling all of the car’s windows down, it flew right out of the other window on the passenger side. But before everyone could expre... | {
"domain": "physics.stackexchange",
"id": 31903,
"lm_label": null,
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"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "newtonian-mechanics, relative-motion",
"url": null
} |
telescope, photography, size
Title: How to determine the scale on astronomical images? I've always been amazed at the many beautiful images of objects in the night sky. The Andromeda galaxy is a superb example. But it was only a few years ago that I discovered that Andromeda in those images is about six times bigger... | {
"domain": "astronomy.stackexchange",
"id": 6231,
"lm_label": null,
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"lm_q2_score": null,
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"openwebmath_score": null,
"tags": "telescope, photography, size",
"url": null
} |
the-sun, mathematics, artificial-satellite, satellite, eclipse
# Validate the results
for index, row in validation_data.iterrows():
total_checks += 1
# extract args for function
sun_earth_position_vector_teme = np.array(
[row["Sun_Earth_Position_TEME_X_km"], row["Sun_Earth_Posit... | {
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"id": 7156,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "the-sun, mathematics, artificial-satellite, satellite, eclipse",
"url": null
} |
homework-and-exercises, energy, work
Title: how to use the energy work kinetic theorem A single force acts on a $3.4~\text{kg}$ particle-like object in such a way that the position of the object as a function of time is given by $x = 4.2t - 2.1t^2 + 2.5t^3$, with $x$ in meters & $t$ in seconds. Find the work done on t... | {
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"tags": "homework-and-exercises, energy, work",
"url": null
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## 1 Answer
For $|z| < 4$,
\begin{align}\frac 2{z - 4} &= \frac 2{-4}\frac 1{1 - \frac z 4}\\ &=\frac {-1}2\sum_{n=0}^\infty \left(\frac z4\right)^n\\ &=-\sum_{n=0}^\infty\frac {z^n}{2^{2n+1}}\end{align}
For $|z| > 4$, \begin{align}\frac 2{z - 4} &= \frac 2{z}\frac 1{1 - \frac 4 z}\\ &=\frac 2z\sum_{n=0}^\infty \lef... | {
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"openwebmath_score": 0.996165931224823,
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homework-and-exercises, classical-mechanics, statistical-mechanics, phase-space
For $x$ around $0$, this is just a rectangle with width $\text dx$ and height $\text dE$, and the total volume is given by the ellipse formula $\pi r_1r_2$. After some algebra, this doesn't lead to the same answer as in a).
Should a) give ... | {
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"tags": "homework-and-exercises, classical-mechanics, statistical-mechanics, phase-space",
... |
context-free
Title: How does this context-free grammar generate even length strings on either side? I came across this context-free grammar for the language L = {xy||x|=|y|, x≠y}, but I can't seem to see how it can generate all lengths for x and y. Could someone illustrate this? For example, how would you derive the s... | {
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"openwebmath_score": null,
"tags": "context-free",
"url": null
} |
deep-learning, keras, tensorflow, image-classification, data-science-model
# perform one-hot encoding on the labels
lb = LabelBinarizer()
labels = lb.fit_transform(labels)
labels = to_categorical(labels)
# partition the data into training and testing splits using 75% of
# the data for training and the remaining 25% f... | {
"domain": "datascience.stackexchange",
"id": 8902,
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"openwebmath_score": null,
"tags": "deep-learning, keras, tensorflow, image-classification, data-science-model",
... |
thermodynamics, statistical-mechanics
Title: Why do particles of an ideal gas move in random motion? Suppose we imagine that the particles (no molecules) of a helium gas are all initially moving horizontally at the same speed.(there is no interaction among them, and the container is ideal, in the sense that the partic... | {
"domain": "physics.stackexchange",
"id": 91646,
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"tags": "thermodynamics, statistical-mechanics",
"url": null
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• Only when the remaining element in column are all zero entry, this is when we cannot proceed any further (no matter usual LU or LU with partial pivoting). – Draditate Aug 27 '20 at 4:29
• OK, so it sounds like we must first calculate all possible $u_{i,k}$ values in column $k$ before deciding which one to use as the ... | {
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"lm_q2_score": 0.8577681049901037,
"openwebmath_perplexity": 406.2211329714761,
"openwebmath_score": 0.9293145537376404,
"tag... |
sorting, quicksort
What am I getting wrong?
Can hi be used for pivoting or there is a very specific fundamental reason to pick A[lo]? "The devil is in the details". Algorithms and programming, fortunately and unfortunately, needs the greatest attention to detail.
The part of code that are critical here are the followi... | {
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"openwebmath_score": null,
"tags": "sorting, quicksort",
"url": null
} |
classical-mechanics, lagrangian-formalism, hamiltonian-formalism
Of course, the above example and Eq. (A) are only true in the simple free particle case. However, it turns out (but is left as an exercise to the reader to show) that in the general one-dimensional case we can still write:
$$
\frac{\partial S_{cl}}{\part... | {
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"tags": "classical-mechanics, lagrangian-formalism, hamiltonian-formalism",
"url": null
} |
nlp, text-mining, preprocessing
So you are in effect trading [representation accuracy and explanatory power] Vs. [space (bounded predictable memory usage) and time (no multiple passes on the data)].
Answers to your specific questions
There is a (sort) correlation between input words and features: through the hash fun... | {
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"tags": "nlp, text-mining, preprocessing",
"url": null
} |
biochemistry, proteins, cheminformatics, crystallography, x-ray-diffraction
So it references Q5CYZ2, and the sequence there is:
10 20 30 40 50
SEFLFSKHLF IFFILKMIER RKIAVIGSGQ IGGNIAYIVG KDNLADVVLF
60 70 80 90 100
DIAEGIPQGK ALDITHSMVM FGS... | {
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"id": 16080,
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"openwebmath_score": null,
"tags": "biochemistry, proteins, cheminformatics, crystallography, x-ray-diffraction",
... |
kinematics, manipulator
Title: Short distance ball transport I'm looking for a way to transport balls (diameter 50mm) 220 mm up with over a slope with a length of 120 mm. Currently I'm considering the usage of a belt system but I cannot seem to find a good belt system.
Because of space constraints within my robot, nor... | {
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"id": 471,
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"openwebmath_score": null,
"tags": "kinematics, manipulator",
"url": null
} |
python, datetime, python-2.x
log_file = """2015-01-1,0,Add,DW_05
2015-01-2,-1,Post,CR_02
2015-01-3,-1,Comp,DIY_01
2015-01-3,-1,Post,CD_01
2015-01-4,-1,Miss,D_03
2015-01-4,0,Miss,D_03
2015-01-4,-1,Miss,CD_01
... | {
"domain": "codereview.stackexchange",
"id": 11689,
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"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "python, datetime, python-2.x",
"url": null
} |
programming, entanglement, measurement, noise, cirq
I can create entangled state with hadamard and cnot gate but I want to create seperable state. How can I create seperable state with cirq
5)For measurement, Should I measure each part seperately or should I first appending all circuit and then measured together? Wha... | {
"domain": "quantumcomputing.stackexchange",
"id": 2041,
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"lm_q2_score": null,
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"openwebmath_score": null,
"tags": "programming, entanglement, measurement, noise, cirq",
"url": null
} |
matlab, discrete-signals, continuous-signals, terminology
Title: Confused in difference between sequence versus signal? I am learning basics of signals and systems with MATLAB
If i create a vector in matlab such that
x=[ 2 5 10 20], will it be considered a sequence or a signal?
As far my learning/knowledge is, x is a... | {
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"tags": "matlab, discrete-signals, continuous-signals, terminology",
"url": null
} |
electromagnetism
Title: How to calculate electric flux of special conditions? How to calculate the electric flux on something which has only one side like Klein bottle or a Möbius ring? The flux would always be zero because for every $d\mathbf{A}$ pointing in one direction there's a corresponding $d\mathbf{A}$ pointin... | {
"domain": "physics.stackexchange",
"id": 56368,
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"lm_q2_score": null,
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"openwebmath_score": null,
"tags": "electromagnetism",
"url": null
} |
slam, navigation, path, hector, action-server
Title: draw the path with hector slam
hello every one, I am using the hector slam with hokuyo. i do have have the map but i need to see the path of the robot on Rviz
can anyone help me please | {
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"tags": "slam, navigation, path, hector, action-server",
"url": null
} |
javascript, jquery, optimization
"liLU2tEz7KY", "eHCyaJS4Cbs", "uEIPCOwY4DE", "V2XGp5ix8HE", "DrQRS40OKNE", "BBcYG_J3O2Q", "upxzaVMhw8k",
"0XcN12uVHeQ", "itvJybdcYbI", "l7iVsdRbhnc", "51V1VMkuyx0", "aQQeg3jYgOA", "XGK84Poeynk", "MaCZN2N6Q_I",
"9q5pZ49r9aU", "DFM140rju4k", "qHBVnMf2t7w", "YtO-6X... | {
"domain": "codereview.stackexchange",
"id": 6618,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "javascript, jquery, optimization",
"url": null
} |
neural-networks, feedforward-neural-networks, graph-neural-networks, embeddings
Title: Is "node embedding" in GNN analogous to "hidden layer" of FFN? So in Graph Neural Network (GNN) we have node embeddings which is a feature vector that describes the node, is it analogous to hidden layer of Artificial neural network ... | {
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"openwebmath_score": null,
"tags": "neural-networks, feedforward-neural-networks, graph-neural-networks, embeddings",
"url... |
frequency, frequency-modulation
$$\begin{cases}
y_1=\sin(2\pi (ax_1+b) x_1+C)\\
y_2=\sin(2\pi (ax_2+b) x_2+C)
\end{cases}$$ | {
"domain": "dsp.stackexchange",
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"tags": "frequency, frequency-modulation",
"url": null
} |
# sums of normal random variables need not be normal
A common misconception among students of probability theory is the belief that the sum of two normally distributed (http://planetmath.org/NormalRandomVariable) random variables is itself normally distributed. By constructing a counterexample, we show this to be fals... | {
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"openwebmath_score": 0.9247846007347107,
"tags"... |
c++, recursion, template, c++20, constrained-templates
// recursive_transform function implementation (the version with unwrap_level, without using view)
template<std::size_t unwrap_level = 1, class T, class F>
requires (unwrap_level <= recursive_depth<T>()&& // handling incorrect unwrap levels more g... | {
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"tags": "c++, recursion, template, c++20, constrained-templates",
"url": null
} |
homework, aqueous-solution, solutions
$1~\mathrm{M}\ \ce{KCl}$. One cation, one anion. Thus, there are two moles of dissolved particles per mole of compound; giving $2~\mathrm{M}$ effective particle concentration.
$0.75~\mathrm{M}\ \ce{C6H21O6}$. This compound is not ionic. Thus, it does not dissociate and one mole di... | {
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"tags": "homework, aqueous-solution, solutions",
"url": null
} |
c#, compression, pdf
int length = d.LengthBuffer[ bufferRead ];
int distance = d.DistanceBuffer[ bufferRead ];
bufferRead = ( bufferRead + 1 ) & d.BufferMask;
byte [] input = d.Input;
while ( position < matchPosition )
{
Lit.Used[ input[ position ] ] += 1;
... | {
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"tags": "c#, compression, pdf",
"url": null
} |
newtonian-mechanics, forces, orbital-motion, centripetal-force
As long as the string is in tension, $\vec F_{\rm g} + \vec F_{\rm T} = m\,\vec a$ which can be divided into a radial component and a tangential component as shown in the right-hand diagram.
Radial: $-F_{\rm T} + F_{\rm g,r} = m \,a_{\rm centripetal}$
Tang... | {
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"tags": "newtonian-mechanics, forces, orbital-motion, centripetal-force",
"url": null
} |
c++, c++11, blockchain
#include <chrono>
Block make_block(std::string const& data,
sha_t const& prevBlockHash)
{
using namespace std::chrono;
milliseconds ms = duration_cast<milliseconds>(system_clock::now().time_since_epoch());
uint64_t timestamp = ms.count();
data_t d(data.begin(),... | {
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"tags": "c++, c++11, blockchain",
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navigation, ekf, robot-localization, ekf-localization-node
<param name="odom0_differential" value="true"/>
<param name="imu0_differential" value="true"/>
<param name="odom0_relative" value="false"/>
<param name="imu0_relative" value="false"/>
<param name="imu0_remove_gravitational_acceleration" value="true"... | {
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"id": 22704,
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"tags": "navigation, ekf, robot-localization, ekf-localization-node",
"url": null
} |
organic-chemistry, acid-base, esters, stereoelectronics
Extra: in a later article, Houk and Jorgensen11 revisited the topic to calculate the potential effects of solvation. A polar solvent would be expected to preferentially stabilise the more polar (E)-conformers 1 and 1a (which are more polar since the dipoles reinf... | {
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"tags": "organic-chemistry, acid-base, esters, stereoelectronics",
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operating-systems, concurrency, synchronization, mutual-exclusion
if (read_count == 0)
signal(rw_mutex); //Line 04
signal(mutex);
} while (true);
Now suppose following sequence of events occurs:
Suppose a first reader comes and it blocks the writer on the line mentioned as Line 02 in comments.
Then a wr... | {
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The exception to the second "usually" above is when the improper Riemann integral doesn't exist but the Lebesgue integral does. This is a pretty uncommon situation in practice.
• @Iterator516 No, the integrals in both of those cases converge absolutely. – Ian Oct 30 at 15:30
• Awesome! Thank you! – Iterator516 Oct 30 ... | {
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"openwebmath_score": 0.8887693285942078,
"tags"... |
If $$x = 452$$, then $$S(99) + S(353) = 29$$ which is the maximum possible. How do I come up with this and prove the same?
• What is $n$ in the requirement $a+b=n$? – 5xum Oct 5 '18 at 11:29
• I assume $n=x$, no? As a small point, you say that you are allowing $b=n$ but that would make $a=0$ which you are not allowing... | {
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"openwebmath_score": 0.9099074006080627,
"ta... |
special-relativity, speed-of-light, reference-frames
But it is also true that in $S$, $P1$ will take an longer time to cross $O$ than $P2$.
How is this possible?
There are various ways to begin understanding how. Here is one.
Go back to the rest frame of $O$, and assume $P1$ and $P2$ enter $O$ at the same time. They t... | {
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"tags": "special-relativity, speed-of-light, reference-frames",
"url": null
} |
rviz, ros-melodic, rosbag, pointcloud
Title: Unable to visualise point cloud from rosbag file in RViz
I have a .bag file which should contain point cloud and RGBD images. However, I'm unable to visualise them in RViz whilst playing the .bag file. This is what I have done:
Record using rosbag record camera/depth_regi... | {
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"tags": "rviz, ros-melodic, rosbag, pointcloud",
"url": null
} |
c++, parsing
key = aw_strToLower(line.substr(0,deli));
val = line.substr(deli+1);
/* CHECK THE KEY IS VALID */
if(!isNameValid(key)){
m_error_line = lineNumber;
m_error = AWESOME_ERROR_PARSING_INVALID_NAME;
if(AWI_REMOVE_DATA_ON_ERROR){
clea... | {
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"id": 12571,
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"tags": "c++, parsing",
"url": null
} |
complexity-theory, turing-machines, computation-models, randomized-algorithms
However, you don't really need an infinite number of coins to get $\mathsf{ZPP}$, and could do with an exponential amount of coins. Suppose $L\in\mathsf{ZPP}$, hence there exists a probabilistic Turing machine $M(x)$, such that for all $x\in... | {
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"tags": "complexity-theory, turing-machines, computation-models, randomized-algorithms",
"url":... |
php, mysql
Title: MySQL limit across multiple tables in multiple queries I have a website that keeps track of 'changes' that users make. These changes come in all shapes and sizes and each shape and size has a different MySQL table to store them in. In total there are 8 different tables. Each table has completely diff... | {
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"tags": "php, mysql",
"url": null
} |
GMAT Question of the Day - Daily to your Mailbox; hard ones only
It is currently 23 Jun 2018, 03:28
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You... | {
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"id": null,
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"lm_q2_score": 0.8539127510928476,
"openwebmath_perplexity": 1201.6486192115208,
"openwebmath_score": 0.7092899084091187,
"tags":... |
general-relativity, fluid-dynamics, differential-geometry, tensor-calculus, vortex
Title: 3-divergence of vorticity vector in GR In Relativistic Cosmologies (Ellis, Maartens, MacCallum), the authors claim that (page 86, section 4.7)
$$
\overline{\omega^i{}_{;i}} = \omega^i\dot{u}_i.\tag{A}
$$
Here $u_i$ is a timelike ... | {
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"tags": "general-relativity, fluid-dynamics, differential-geometry, tensor-calculus, vortex... |
c#, design-patterns, interview-questions, state
public int RefundMoney()
{
_state = new Canceling(this);
var (product, refund) = _state.DoWork();
CashInserted = 0;
return refund;
}
public void ResetMachine()
{
CashInserted =... | {
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"tags": "c#, design-patterns, interview-questions, state",
"url": null
} |
The answer that I got is $-6:25$.
Using your formula $x=1,y=3, p=2,q=9$
So, $P\left(\frac{2m+n}{m+n},\frac{9m+3n}{m+n}\right)$
Now, as the points $P,A,B$ are collinear, the are of the $\triangle PAB=0$
We can use this formula to calculate the area of of the triangle. | {
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"lm_q2_score": 0.8289388019824946,
"openwebmath_perplexity": 301.47701880444316,
"openwebmath_score": 0.8774667382240295,
"ta... |
mechanical-engineering, materials, civil-engineering, industrial-engineering, strength
Title: Why does the stress-strain curve decrease? This is a stress-strain diagram
I have noticed that the curve decreases between points C & D and between E & F.
Why does that happen? I expected the curve to always increase since... | {
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"tags": "mechanical-engineering, materials, civil-engineering, industrial-engineering, s... |
Starting with $f(k) = 1$, we have $\Delta f(k) = 0$. Since $B(0,n-1)$ is clearly $0$, $B(1,n) = [n=0]$. The latter is just the known formula $$\sum_{k=0}^n (-1)^k \binom{n}{k} = [n=0].$$
Then, continuing to take antidifferences, and using the notation $k^{\underline{m}}$ for the falling factorial $k(k-1)\cdots (k-m+1)... | {
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"lm_q2_score": 0.8152324848629215,
"openwebmath_perplexity": 177.45220775997728,
"openwebmath_score": 0.9693893194198608,
"ta... |
ros, sbpl-lattice-planner, header
how to solve?
thankyou
Originally posted by gautam on ROS Answers with karma: 1 on 2012-07-04
Post score: 0
Original comments
Comment by piyushk on 2012-07-09:
@gautam: can you paste the exact error that you receive regarding sbpllatticeplannerstats.h? I can build the stack just fin... | {
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"tags": "ros, sbpl-lattice-planner, header",
"url": null
} |
into their imaginations and invented a whole new set of numbers be. Series ODE Multivariable Calculus Laplace Transform Taylor/Maclaurin Series Fourier … polar complex numbers into rectangular.. And invented a whole new set of numbers can be thought of as modified! Acharjya on 4 Sep 2019 returns: this function returns ... | {
"domain": "spek.gr",
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"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9465966702001757,
"lm_q1q2_score": 0.8241044674153216,
"lm_q2_score": 0.8705972600147106,
"openwebmath_perplexity": 1269.2017764593807,
"openwebmath_score": 0.8296555280685425,
"tags": n... |
matlab, sampling, fourier-series, approximation
sum_ = sum((((1:N)-2*N-2).*(cos(pi*(1:N))-1).*sin((1:N).*w.*(0:1/fs:1)'))./(2*pi*(1:N)*(N + 1)), 2);
Ffej = 2*sum_;
Ffej = Ffej';
plot(t,Ffej);
axis([r_start r_end -1.2 1.2]);
legend('Square', 'Fourier series-Fejér taper');
audiowrite("appr... | {
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"tags": "matlab, sampling, fourier-series, approximation",
"url": null
} |
quantum-field-theory, feynman-diagrams, correlation-functions, greens-functions, propagator
\end{align}
Of course, $z_\text{bubble}-xy=0$, so the bubbles indeed cancel at the order of two loops.
Finally, I think that the argument of Schwartz after the "more generally" in your quote is correct. Intuitively, just think ... | {
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"tags": "quantum-field-theory, feynman-diagrams, correlation-functions, greens-functions, p... |
perfect positive correlation. If positive, the two variables in the _____ coefficient _____ in the _____ direction. If we are observing samples of A and B over time, then we can say that a positive correlation between A and B means that A and B tend to rise and fall together. Standard deviation is a measure of the disp... | {
"domain": "bil-service.nu",
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"lm_q1_score": 0.9719924802053235,
"lm_q1q2_score": 0.807864796558659,
"lm_q2_score": 0.8311430520409023,
"openwebmath_perplexity": 903.3986671017237,
"openwebmath_score": 0.7978814244270325,
"tags": ... |
rosnode, rosrun
Originally posted by cyborg-x1 with karma: 1376 on 2015-06-29
This answer was ACCEPTED on the original site
Post score: 1
Original comments
Comment by nemesis on 2015-07-28:
The script I have posted above is required because it's part of a bigger set of commands. So the above gets called, followed by ... | {
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"tags": "rosnode, rosrun",
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} |
array, node.js, json, api, classes
do I need to keep what's inside the constructor method?
What you wrote looks good to me, modulo my remarks.
Not sure what you would get rid of;
it seems sensible from where I'm sitting.
day vs hour-within-day
validTimeLocal: ['2024-02-09T07:00:00-0500',
'2024-02... | {
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"openwebmath_score": null,
"tags": "array, node.js, json, api, classes",
"url": null
} |
matlab, complex, parameter-estimation
Title: Is the calculation of variance correct from an estimator -- confusion regarding complex number where I am going wrong? I have an expression for the varaince of measurement noise obtained from an estimator. The measurement noise is additive white gaussian having values in co... | {
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"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "matlab, complex, parameter-estimation",
"url": null
} |
general-relativity, cosmology, metric-tensor, field-theory, klein-gordon-equation
Title: Deriving Klein-Gordon equation in curved spacetime I try to drive The Klein-Gordon equation for a massless scalar field in case of FRW metric:
$$
ds^2= a^2(t) [-dt^2 + dx^2]
$$
So I start by:
$$\left(\frac{1}{g^{1/2}}\partial_{\mu... | {
"domain": "physics.stackexchange",
"id": 98961,
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"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "general-relativity, cosmology, metric-tensor, field-theory, klein-gordon-equation"... |
genetics, cell-biology
Title: Is the number of nucleoli in a nucleus fixed? A nucleus can have multiple nucleoli. But are there any constraints on the number of nucleoli in a nucleus?
Can cells of individuals of different species have a different number of nucleoli?
Can cells of different individuals of the same spec... | {
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"id": 11153,
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"openwebmath_score": null,
"tags": "genetics, cell-biology",
"url": null
} |
simulation and historical simulation are both methods that can be used... 3,000 CFA® Exam Practice Questions offered by AnalystPrep – QBank, Mock Exams, Study Notes, and Video Lessons, 3,000 FRM Practice Questions – QBank, Mock Exams, and Study Notes. We measure “spread” using range, interquartile range, variance, and ... | {
"domain": "swiftmotionpictures.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9752018354801189,
"lm_q1q2_score": 0.8327372803928623,
"lm_q2_score": 0.8539127492339909,
"openwebmath_perplexity": 659.9377973614301,
"openwebmath_score": 0.83931154012680... |
Vectorizing the Notion of Colon (:)
The other day, one of my MathWorks buddies, Peter, asked me if I knew any tricks for vectorizing the notion of the colon (:) operator. For me, this sort of inquiry sometimes has an effect similar to waving a flag in front of a bull! The challenge was on.
I know people have posted m... | {
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"lm_q1_score": 0.9724147193720649,
"lm_q1q2_score": 0.8124364912640957,
"lm_q2_score": 0.8354835391516133,
"openwebmath_perplexity": 3984.7478250679173,
"openwebmath_score": 0.3309597373008728,
"tags":... |
python, numpy, simulation, matplotlib
# Redraw...
coords = np.transpose(np.nonzero(grid != 0))
x_pts, y_pts, idents = zip(*coords)
points.set_data(x_pts, y_pts)
fig.canvas.restore_region(background) # Restore background
ax1.draw_artist(points) # Redraw just the points
... | {
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"tags": "python, numpy, simulation, matplotlib",
"url": null
} |
c++, algorithm, c++11, linked-list, reinventing-the-wheel
since you maintain a head pointer in your class, you should make use of it to push_back (with O(1) complexity), or dispense with it altogether.
std::shared_ptr<ListNode> currNode = std::make_shared<ListNode>(val);
if (head) {
std::shared_ptr<Lis... | {
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"tags": "c++, algorithm, c++11, linked-list, reinventing-the-wheel",
"url": null
} |
ros, python, ros-fuerte, roscreate-pkg
Title: Can't create a package
I have a problem with creating a package with roscreate-pkg. At the beginning I was create a package without any error messages. Now I get something like this while attempting to create a package:
Traceback (most recent call last):
File "/opt/ros/fu... | {
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"tags": "ros, python, ros-fuerte, roscreate-pkg",
"url": null
} |
Thomas Jr. The acceleration of an object is the derivative of its speed. | All the textbo…. Again, if all the values of (r, φ) of a curve are related by some equation which can be symbolically written. To simulate the system let's first create the methods to draw the balls and the strings that hold them together. We ca... | {
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"id": null,
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"lm_q1_score": 0.990140142659816,
"lm_q1q2_score": 0.8251081316348945,
"lm_q2_score": 0.8333245932423308,
"openwebmath_perplexity": 406.21296170265595,
"openwebmath_score": 0.9168432354927063,
"t... |
gazebo, ros2, rviz, turtlebot
Title: Map is not initialized, with Rviz and Gazebo simulation, ROS2
Hi. I have been following the Turtlebot3 tutorial with ROS2 Dashing (http://emanual.robotis.com/docs/en/platform/turtlebot3/ros2/#ros2) which works fine for all the steps.
Now, i want to try out simulation in gazebo and... | {
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"openwebmath_score": null,
"tags": "gazebo, ros2, rviz, turtlebot",
"url": null
} |
waves
Title: Stationary wave in a string When a stationary wave is generated in a string meanwhile if the tension in the string is also increased, what will be the effect on the speed of standing wave in the string? If you asked this question, I think you don't know this equation
$$v=\sqrt{\frac{F} {\rho}}$$
where $\... | {
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"tags": "waves",
"url": null
} |
which contains the sought addition law.
$$\color{#c00}{F_{n+m} = F_nF_{m+1} + F_{n-1}F_m}$$
That is but a small glimpse of the power afforded by linear representations.
Simply notice that $$\begin{bmatrix}a & -b\\ b & a\end{bmatrix}=aI+bJ$$
where $I=\begin{bmatrix}1 & 0\\ 0 & 1\end{bmatrix}$ and $J=\begin{bmatrix}0... | {
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"lm_q1_score": 0.9828232909876816,
"lm_q1q2_score": 0.801229484722969,
"lm_q2_score": 0.8152324960856175,
"openwebmath_perplexity": 228.44758068752097,
"openwebmath_score": 0.8560912013053894,
"tag... |
organic-chemistry, synthesis
Title: Grignard formation and vicinal dihalides So let's say I have a symmetric 1,2-dihalide (the halides are identical) and I wanted to make a Grignard and I only add 1 eq. of magnesium metal ...
Will I get 1 eq. of asymmetric Grignards (i.e. only one side of the product has the C-MgBr b... | {
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"lm_q2_score": null,
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"openwebmath_score": null,
"tags": "organic-chemistry, synthesis",
"url": null
} |
machine-learning, neural-network, deep-learning, training, gpu
Title: What's the advantage of multi-gpu training in real? The decreasing speed of training loss is almost the same between one gpu and multi-gpu.
After averaging the gradients, the only benefit from multi-gpu is that the model seems to see more data in th... | {
"domain": "datascience.stackexchange",
"id": 9032,
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"openwebmath_score": null,
"tags": "machine-learning, neural-network, deep-learning, training, gpu",
"url": null
... |
energy, energy-conservation, antimatter, higgs, dark-energy
Title: Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson? Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson and all kind of these like stuffs... | {
"domain": "physics.stackexchange",
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"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "energy, energy-conservation, antimatter, higgs, dark-energy",
"url": null
} |
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