ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Tue, 11 Apr 2017 04:50:37 -0500symbolic vector normhttp://ask.sagemath.org/question/8804/symbolic-vector-norm/I can't get Sage to produce the norm or even just compute `w[1]^2` in the code below. I keep getting a "not implemented" error. Have I made a simple mistake here, or is there a way around this? Thanks for the help. I haven't done much with matrix computations in Sage yet and am trying to learn my way around.
var('x,y')
a=matrix([[1,2],[-3,0]])
v=vector([x,y])
w=a*v.column()
w.norm()Mon, 19 Mar 2012 10:25:19 -0500http://ask.sagemath.org/question/8804/symbolic-vector-norm/Comment by mforets for <p>I can't get Sage to produce the norm or even just compute <code>w[1]^2</code> in the code below. I keep getting a "not implemented" error. Have I made a simple mistake here, or is there a way around this? Thanks for the help. I haven't done much with matrix computations in Sage yet and am trying to learn my way around.</p>
<pre><code>var('x,y')
a=matrix([[1,2],[-3,0]])
v=vector([x,y])
w=a*v.column()
w.norm()
</code></pre>
http://ask.sagemath.org/question/8804/symbolic-vector-norm/?comment=37260#post-id-37260[updated link](https://trac.sagemath.org/ticket/12733)Tue, 11 Apr 2017 04:50:37 -0500http://ask.sagemath.org/question/8804/symbolic-vector-norm/?comment=37260#post-id-37260Comment by Jason Grout for <p>I can't get Sage to produce the norm or even just compute <code>w[1]^2</code> in the code below. I keep getting a "not implemented" error. Have I made a simple mistake here, or is there a way around this? Thanks for the help. I haven't done much with matrix computations in Sage yet and am trying to learn my way around.</p>
<pre><code>var('x,y')
a=matrix([[1,2],[-3,0]])
v=vector([x,y])
w=a*v.column()
w.norm()
</code></pre>
http://ask.sagemath.org/question/8804/symbolic-vector-norm/?comment=20076#post-id-20076This is an error in symbolic matrices (v.column() makes w a symbolic matrix, not a symbolic vector). I've opened a ticket here: http://trac.sagemath.org/experimental/ticket/12733Thu, 22 Mar 2012 21:53:46 -0500http://ask.sagemath.org/question/8804/symbolic-vector-norm/?comment=20076#post-id-20076Answer by achrzesz for <p>I can't get Sage to produce the norm or even just compute <code>w[1]^2</code> in the code below. I keep getting a "not implemented" error. Have I made a simple mistake here, or is there a way around this? Thanks for the help. I haven't done much with matrix computations in Sage yet and am trying to learn my way around.</p>
<pre><code>var('x,y')
a=matrix([[1,2],[-3,0]])
v=vector([x,y])
w=a*v.column()
w.norm()
</code></pre>
http://ask.sagemath.org/question/8804/symbolic-vector-norm/?answer=13377#post-id-13377 sage: var('x,y')
(x, y)
sage: a=matrix([[1,2],[-3,0]])
sage: v=vector([x,y])
sage: w=a*v
sage: w.norm()
sqrt(abs(x + 2*y)^2 + abs(-3*x)^2)
Mon, 19 Mar 2012 11:15:18 -0500http://ask.sagemath.org/question/8804/symbolic-vector-norm/?answer=13377#post-id-13377