I am trying to make a function of a variable with sage for example:
f(x) = sin(x)
f(x+y)
yields:
sin(x+y)
However if It is in a matrix this no longer works:
f(x) = matrix([[sin(x)],[cos(x)]])
f(x+y)
yields:
sin(x)
cos(x)
Is this not possible or am I missing something to make this work?
I am using sage 7.3 on Ubuntu 16.04 with the aims ppa.
If you ask for the type of $f$, you get <ππ’ππ'ππππ.ππ’ππππππ.ππ‘ππππππππ.π΄π‘ππππππππ'>: apparently the substitution into symbolic expressions is not overloaded to matrix-valued functions. However, with
var('x y')
f = matrix(SR, [[sin(x)],[cos(x)]])
type(f)
you get <ππ’ππ'ππππ.ππππππ‘.ππππππ‘β―ππ’ππππππβ―πππππ.πΌπππππ‘β―ππ’ππππππβ―πππππ'>, and
f(x=x+y)
gives the expected result.
Alternatively, try with:
def f(x): return matrix(SR, [[sin(x)],[cos(x)]])
to obtain an object $f$ of type 'function'.
Asked: 2016-10-10 03:19:04 +0100
Seen: 843 times
Last updated: Oct 10 '16
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