any possibility of using "chaospy.poly.base.Poly" object as python symbolic expression

[cc636489]

Hi, Jonathan,

First, thank you for this nice package, it's light and helpful! I am currently exploring it with fun!

My question is about using "chaospy.poly.base.Poly" object as python symbolic expression. Is that possible? Since we can do the following:

print orthpol[3]
q1^2-2.0q1+0.986666666667

I can change the result to a string by doing str(orthpol[3]), which is convenient for further symbolic integration. However, the expression presented above is not a valid python expression. So is there any possibility that I can make use of the orthogonalized polynomials freely generated by chaospy? and how?

Thank you in advance for your time and consideration!

Cheers,
Chen

[jonathf]

Interesting usecase. I have support for this unexposed in the API, and it isn't complicated to expose it to accommodate your need. I just pushed a commit to the development branch allowing for the following:

import chaospy as cp

cp.poly.base.POWER = "**"
cp.poly.base.SEP = "*"

q0 = cp.variable()
orth = q0**2-2.*q0+0.98666666666666
print(eval(str(orth)))
# q0**2-2.0*q0+0.986666666667

[jonathf]

Also note, if the plan is to parse the coefficients or extract components, there are functions for that too:

print(cp.decompose(orth))
# [0.986666666667, -2.0*q0, q0**2]
print(orth.coeffs())
# [ 0.98666667 -2.          1.        ]

[cc636489]

Thanks Jonathan, It's exactly what I want and works great! Yeah, I agree it's an API issue based on the following experiment:

>> a = cp.variable() >> expr = 12*a+a**2 >> print expr

q0^2+12q0

>>cp.poly.base.POWER = "**" >>cp.poly.base.SEP = "*" >>print expr

q0**2+12*q0 Thank you again for the quick reply! Chen

…

On Wed, May 31, 2017 at 6:54 AM, Jonathan Feinberg ***@***.*** > wrote: Also note, if the plan is to parse the coefficients or extract components, there are functions for that too: print(cp.decompose(orth)) # [0.986666666667, -2.0*q0, q0**2] print(orth.coeffs()) # [ 0.98666667 -2. 1. ] — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#48 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AWCYACUJF4dy04uQdCPAzByUcBrN0Zc7ks5r_VUIgaJpZM4NrEwJ> .

-- Chen CHEN Graduate Student in ICES&EM POB 3.402J The University of Texas at Austin Phone: +1 512-968-2126 Email : [email protected]

[jonathf]

I consider this issue as solved. Feel free to reopen if you feel this is not the case.