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## Can I, in D&D, as a DM, create a new class entirely? (5e) If I can, how do I develop class features?

See, I believe my campaign needs a new class entirely. As in, you can choose from barbarian, rogue, new class name, etc. I looked at the DMG and it says literally nothing about creating a new class from scratch. So I want to know if it is possible to do so. If it is, I […]

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## Compact way to regulate 3000psi (200bar) down to 30psi (2bar)?

This was originally posted on the Lego page, and closed because it’s not actually about Lego itself. I thought I’d give them a chance first, in case someone had done this already and had some application-specific knowledge. Then my next stop is here, since you guys are probably more familiar with the gear that I’m […]

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## Problem in Convergence of TD(n) algorithm

Given equation 7.3 of Sutton and Barto’s book for convergence of TD(n): $\max_s|\mathbb{E}_\pi[G_{t:t+n}|S_t = s] – v_\pi(s)| \leqslant \gamma^n \max_s|V_{t+n-1}(s) – v_\pi(s)|$ PROBLEM 1 : Why is this error $|\mathbb{E}_\pi[G_{t:t+n}|S_t = s] – v_\pi(s)|$ compared with the error $|V_{t+n-1}(s) – v_\pi(s)|$. There can be two other logical comparisons for the convergence of algorithm($TD(n)$): 1) If […]

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## Why isn’t my decision tree classifier able to solve the XOR problem properly?

I was trying to solve an XOR problem, and the dataset seems like the one in the image. I plotted the tree and got this result: As I understand, the tree should have depth 2 and four leaves. The first comparison is annoying, because it is close to the right x border (0.887). I’ve tried […]

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## loss not reducing in tensorflow classification attempt

I wanted to simulate classifying whether a student will pass or fail a course depending on training data with a single input, namely a student’s exam score. I start by creating data set of test scores for 1000 students, normally distributed with a mean of 80. I then created a classification “1” (passing) for the […]

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## Ruby sort order of array of hash using another array in an efficient way eg O(1) or O(n log n)

I have some data that I need to export as csv. It is currently about 10,000 records and will keep growing hence I want an efficient way to do the iteration especially with regards to running several each loop, one after the other. My question is that is there a away to avoid the many […]

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## Unnesting tibble columns: “Wide” data summaries with dplyr v1.0.0

I’d like to produce “wide” summary tables of data in this sort of format: —- Centiles —- Param Group Mean SD 25% 50% 75% Height 1 x.xx x.xxx x.xx x.xx x.xx 2 x.xx x.xxx x.xx x.xx x.xx 3 x.xx x.xxx x.xx x.xx x.xx Weight 1 x.xx x.xxx x.xx x.xx x.xx 2 x.xx x.xxx x.xx x.xx […]

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## Proper way to Dispose objects in C# WinForm

In a form that has a couple of DataGridViews I have two DataTables that are changed and accessed in various places throughout the form. I’m instantiating them like this: public partial class frmXRefTool : Form { private DataTable dtXref; private DataTable dtDefaults; Both variable names have green squigglys under them with the message ‘frmXrefTool’ contains […]

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## arm-none-eabi-gdb: cannot insert breakpoint cannot access memory at address

Setup I am working on W10 and I am encountering a problem while following the tutorial from here. It is about writing baremetal code for ARM Cortex M3. The files produced by the above tutorial are startup.c test_program.c and stm32.ld. All three files are in the same folder where I open a cmd window and […]

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## How do i read references given by ptr_refs in iOS?

When printing list of references with ptr_refs, it gives somewhat vague results (at least in iOS). For example I have a sample app with this tiny ViewController class and exactly one outlet reference to a UILabel instance: import UIKit class ViewController: UIViewController { @IBOutlet var label: UILabel! override func viewDidAppear(_ animated: Bool) { super.viewDidAppear(animated) print(label) […]