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Questions tagged [momentum]

73 questions
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Two-dimensional collision with two moving objects

I am working on a two-dimensional collision with two moving objects. Its very simple. I have two spheres which have different geometry and mass. They colide at 45° angle. I need to calculate the velocity vectors of both spheres after the colision. I…
Nejc
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How to fine tune hyper-parameters of momentum optimizer?

There are several optimizers in training of neural network. But the Momentum and SGD seem always better than adaptive methods. Now I am writing a program in tensorflow to reproduce the results of others. They use momentum to train in pylearn2. But…
Kai He
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Why do small tweaks to the momentum constant affect SGD results so greatly?

So I'm just playing around with Keras, and decided to make a simple neural network to do univariate linear regression. (epochs=25, lrate=0.001, decay=100). I notice that when I set momentum in [0.7, 0.9], the r^2 of my regression is always >0.95,…
user49404
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Conservation of angular momentum

I'm working on a 2D physics engine in C#. I've got everything working other than resolving rotation during collisions. I have what I thought was a solution but it causes the objects to bounce insanely high and spin at high speed. I calculate the…
Scott Richmond-Wood
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Momentum portfolio(trend following) quant simulation on pandas

I am trying to construct trend following momentum portfolio strategy based on S&P500 index (momthly data) I used Kaufmann's fractal efficiency ratio to filter out whipsaw signal (http://etfhq.com/blog/2011/02/07/kaufmans-efficiency-ratio/) I…
Wookeun Lee
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Smoothly change direction of an SKPhysicsBody's momentum

I have an SKPhysicsBody in my scene that I apply an impulse to whenever the user presses a button to make it move forwards. Due to it's properties, it doesn't move much with a single tap and slows down fairly rapidly, however with multiple taps it…
Max Chuquimia
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Backpropagation with Momentum using Scikit-Learn

I'm trying to use Scikit-Learn's Neural Network to classify my dataset using a Backpropagation with Momentum. I need to specify these parameters: Hidden neurons, Hidden layers, Training set, Learning rate and Momentum. I found MLPClassifier in…
kbonnelly
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Building portfolios in R:

I tried to ask a similar question earlier, but I see now that it lacked information needed to answer it, so I've tried to make a replicable example now. I want to test the momentum theory on a stock market, and therefore has to make some momentum…
Alfemann
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In a Neural Network, should bias have a momentum term?

Should the momentum be added also to the bias term of every node in the network or preferably only on weights?
user1861248
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Stop an SKPhysicsBody mid-motion

If an SKSpriteNode has had an impulse applied to its SKPhysicsBody so that it now has momentum, is there a way I can get it to immediately stop moving? Applying an equal and opposite impulse would probably work in theory, but I would like to know if…
Lahav
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Creating a Motion Update in JavaFX with Java 8

I had a simple JavaFX game where I moved the character with key codes. I now want to improve upon this and add some "momentum". But with my run method, the my character does not move. Please help. Here is my code with the previous method of moving…
Zombo
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How to simulate a strong joint between two rigid bodies?

I'm having to write my own physics code (if you're curious why, see here). Simulating a single rigid body is pretty simple. But we have assemblies (simulated space colonies) which are composed of multiple rigid bodies, joined by rotating…
Joe Strout
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Multilayer perceptron for ocr works with only some data sets

NEW DEVELOPMENT I recently used OpenCV's MLP implementation to test whether it could solve the same tasks. OpenCV was able to classify the same data sets that my implementation was able to, but unable to solve the one's that mine could not. Maybe…
Josh
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How to prevent flickering on a SlickGrid when updating data and using momentum scroll?

I had created a SlickGrid to be used on an IOS device. I update the data at an interval of 1 second (through a web socket). I had added momentum scrolling on it by adding the following css: .slick-viewport { overflow-y: scroll; …
utsavberi
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Need Unity character controller to make sharp 90 degree turns and not slide when turning

I'm using the first person controller for my characters movement. On a left arrow keypress, I'd like the character to instantly rotate 90 degrees and keep moving forward. Currently, when I hit the arrow key, the character makes the sharp 90 degree…
Paul Mengelt
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