I have to do the minimization of a cost function based on parameters

(gradient descent).

Is there a decent ruby gem (that works with rails) to do this?

Thanks in advance

I have to do the minimization of a cost function based on parameters

(gradient descent).

Is there a decent ruby gem (that works with rails) to do this?

Thanks in advance

Rodrigo R. wrote in post #1040708:

I have to do the minimization of a cost function based on parameters

(gradient descent).Is there a decent ruby gem (that works with rails) to do this?

From what I can tell “gradient descent” is just math:

mistaken):

x_old = 0

x_new = 6 # The algorithm starts at x=6

eps = 0.01 # step size

precision = 0.00001

def f_prime(x):

return 4 * x**3 - 9 * x**2

x_old = x_new

x_new = x_old - eps * f_prime(x_new)

print "Local minimum occurs at ", x_new

Maybe just translating that to Ruby will give you what you want. Note:

I’m no mathematician. You may have to consult someone who is the above

needs any tweaking.

The problem is that the function I’m trying to minimize is a lot more

complicated (so is its derivative), so I wanted a function that could do

the minimization for me rather than implementing one myself

On Friday, January 13, 2012, Robert W. [email protected] wrote:

while abs(x_new - x_old) > precision:

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What libraries did you use?

Rodrigo R. wrote in post #1040810:

The problem is that the function I’m trying to minimize is a lot more

complicated (so is its derivative), so I wanted a function that could do

the minimization for me rather than implementing one myself

I thought it might be something like that. Sorry I don’t know of

anything like that either. Is this something that can be solved with

matrix math? I noticed mention of that in what I was reading. I’ve used

libraries in the past to solve some differential equations, but I had

the advantage of having the matrix equation given to me by the company

that created the device where it was needed.

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