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 <𝚝𝚢𝚙𝚎'𝚜𝚊𝚐𝚎.𝚜𝚢𝚖𝚋𝚘𝚕𝚒𝚌.𝚎𝚡𝚙𝚛𝚎𝚜𝚜𝚒𝚘𝚗.𝙴𝚡𝚙𝚛𝚎𝚜𝚜𝚒𝚘𝚗'>: 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 <𝚝𝚢𝚙𝚎'𝚜𝚊𝚐𝚎.𝚖𝚊𝚝𝚛𝚒𝚡.𝚖𝚊𝚝𝚛𝚒𝚡⎯𝚜𝚢𝚖𝚋𝚘𝚕𝚒𝚌⎯𝚍𝚎𝚗𝚜𝚎.𝙼𝚊𝚝𝚛𝚒𝚡⎯𝚜𝚢𝚖𝚋𝚘𝚕𝚒𝚌⎯𝚍𝚎𝚗𝚜𝚎'>, 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'.
Thanks that answers my question. Is the substitution not being overloaded to matrix valued functions a bug? or a feature that hasn't been implemented? or something that is done on purpose?
Asked: 8 years ago
Seen: 997 times
Last updated: Oct 10 '16
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