Questions tagged [momentum]
8 questions
9
votes
3 answers
What is momentum in neural network?
While using "Two class neural network" in Azure ML, I encountered "Momentum" property. As per documentation, which is not clear, it says
For The momentum, type a value to apply during learning as a weight on
nodes from previous…
Sandeep Bhutani
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6
votes
2 answers
Adam optimizer for projected gradient descent
The Adam optimizer is often used for training neural networks; it typically avoids the need for hyperparameter search over parameters like the learning rate, etc. The Adam optimizer is an improvement on gradient descent.
I have a situation where I…
D.W.
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4
votes
1 answer
Why does momentum need learning rate?
If momentum optimizer independently keeps a custom "inertia" value for each weight, then why do we ever need to bother with learning rate?
Surely, momentum would catch up its magnutude pretty quickly to any needed value anyway, why to bother…
Kari
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3
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0 answers
Dissecting and understanding the Adam optimization's formula
Adam's optimization has the fololwing parameter update rule :
$$ \theta_{t+1} = \theta_{t} - \alpha*\dfrac{m_t}{\sqrt{v_t + \epsilon}}$$ where $$ m_t \text{ is first moment of gradients and} \space v_t \space \text{is second moment of gradient} $$…
black sheep 369
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2
votes
1 answer
Adam Optimiser First Step
Plotting the paths on the cost surface from different gradient descent optimisers on a toy example, I found that the Adam algorithm does not initially travel in the direction of steepest gradient (vanilla gradient descent did). Why might this…
foam78
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1
vote
0 answers
Why does NAG cause unstable validation loss?
I'm building a neural network for a classification problem. When playing around with some hyperparameters, I was surprised to see that using Nesterov's Accelerated Gradient instead of vanilla SGD makes a huge difference in the optimization…
Charles Lagace
- 41
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1
vote
1 answer
Does settings $\beta_1 = 0$ or $\beta_2 = 0$ means that ADAM behaves as RMSprop or Momentum?
I read on ADAM optimizer, and I saw multiple quotes which say that ADAM is a combination of Momentum and RMSprop optimizers.
So if we:
Set $\beta_1 = 0$ does it means that ADAM behaves exactly as RMSprop optimizer?
Set $\beta_2 = 0$ does it means…
user3668129
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1 answer
Is the usage of the "momentum" significiantly superior to the conventional weight update
The "momentum" adds a little of the history of the last weight updates to the actual update, with diminishing weight history (older momentum shares get smaller).
Is it significiantly superior?
Weightupdate:
$$
w_{i+1} = w_i + m_i
$$
With…
Turnvater
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