taylor expansions need work about symbolic HOT 12 CLOSED

Improved but still need 2D expansions and orderMode

from symbolic.

can i try 2D expansions ?

from symbolic.

Sure @trueutkarsh that would be great.

Maybe this is helpful? http://stackoverflow.com/questions/22857162/multivariate-taylor-approximation-in-sympy

from symbolic.

@cbm755 i have written the python code(function) which does it ,tested and compared it with few outputs from the matlab .Its working fine.(i havent checked on when taylor series cant be computed .. will do so soon..)
But I am facing problems in how to incorporate it in octave. Since the function is not present in sympy how I can I use it ?
Thanks

from symbolic.

Sounds great so far.

If you look in inst/@sym/taylor, near the end there is a cmd = { ' ... ' }; bit. This is python code, you can probably do something similar. Fork this project, start a new branch, then send a pull request--- even if its not perfect---we'll help!

from symbolic.

cool that should do the job..
as soon as I'll incorporate it in octave will send a pull request.

from symbolic.

@cbm755 Now that expr=f(x,y) my code needs a list [x,y] as parameter .
"(f, x, a, n) = _ins' " interprets f as expr ,I want it to interpret x as list of variables and 'a' as list of evaluation points .
Right now it throws
"Python exception: TypeError: 'Zero' object does not support indexing
occurred at line 8 of the Python code block
"
'expr=f'
'var=x'
'i=a'
'expn=expr.subs([(var[x],i[x]) for x in range(len(var))]) ' %this is line 8

from symbolic.

Bit hard for me to comment without seeing your whole code... I suggest you start the pull request, even if it doesn't work yet (then I can see the actual code and even check it out).

from symbolic.

here's the pull request #364
Edit 1: is there some other way to contact you other than commenting here since you're not on irc channel and there's not much help for octsympy their.

from symbolic.

Not at the moment, no. I should probably get on IRC.

from symbolic.

@cbm755 I am facing a new problem. the follwing code snippet does'nt seems to work

cmd ={'(f, x, a, n) = _ins'
'z=f'
'if not isinstance(x,list):'
' z=(z.series(x,a,n).removeO())'
'var=list(x)'
'for m in range(len(var)):'
' z=z.series(var[m],a[m],3).removeO()'
'return nsimplify(z)'
};
Using this it woks for single variable taylor series but not multiple variable.
if this code snippet works then we can simply merge mtaylor and taylor.
Rather I am using
cmd ={'(f, x, a, n) = _ins'
'z=f'
'if len(z.atoms(Symbol)) ==1 :'
' return nsimplify(z.series(x,a,n).removeO())'
'var=list(x)'
'for m in range(len(var)):'
' z=z.series(var[m],a[m],3).removeO()'
'return nsimplify(z)'
};
Using this single variable works and multivariable also works
but this case
"mtaylor(sin(x+y),x)" is not working.
What am I missing ? Please help.

from symbolic.

you could just use two cmd and two calls to python python_cmd, one in case numel(x)>1 and one when numel(x) == 1 for now. Once that works, worry about whether code is nicer by merging them...

from symbolic.