How to define finite difference approximation for first order derivative

asked 2016-01-25 12:09:28 -0600

Orange
11 ●1

updated 2016-01-26 02:00:49 -0600

tmonteil
18553 ●21 ●131 ●343 http://wiki.sagemath.o...

I need to define $$y1(k)=\frac{y_{k+1}-y_{k-1}}{2*h}$$

in sage so that sage can differ between symbolic $$y_{k+1}$$ and $$y_{k}$$.

Would somebody please help?

edit retag flag offensive close merge delete

add a comment

1 answer

Sort by » oldest newest most voted

answered 2016-01-26 02:22:44 -0600

tmonteil
18553 ●21 ●131 ●343 http://wiki.sagemath.o...

The question is not clear to me, why not simply do:

sage: Y = [1,2,4,3,7,2,1]
sage: h = 0.1
sage: [(Y[k+1]-Y[k-1])/h for k in  range(1,len(Y)-1)]
[30.0000000000000,
 10.0000000000000,
 30.0000000000000,
 -10.0000000000000,
 -60.0000000000000]

edit flag offensive delete link

Comments

$y_{k+1} $ and $y_k$ needs to remain unknown till the formation of equation, so that they can act as variables in the linear system. My interest is to automate the finite difference method in sage. Should I need to define some new data structure. Thanks for responding though!!!

Orange ( 2016-01-28 06:14:29 -0600 )edit

add a comment

Question Tools

Stats

Asked: 2016-01-25 12:09:28 -0600

Seen: 137 times

Last updated: Jan 26 '16

How to define finite difference approximation for first order derivative

1 answer

Comments

Your Answer

Question Tools

Stats

Related questions

How to define finite difference approximation for first order derivative edit

1 answer

Comments

Your Answer

Question Tools

Stats

Related questions

How to define finite difference approximation for first order derivative