ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 05 Nov 2018 14:00:31 -0600how to get the transformation matrix for a transformation over 4x4 matrices?http://ask.sagemath.org/question/44194/how-to-get-the-transformation-matrix-for-a-transformation-over-4x4-matrices/I have the following transformation:
M = MatrixSpace(QQ,4,4)
def f(m):
return matrix([
[m[0][0], m[0][1], m[0][2], m[0][3]],
[m[1][3], m[1][0], m[1][1], m[1][2]],
[m[2][2], m[2][3], m[2][0], m[2][1]],
[m[3][1], m[3][2], m[3][3], m[3][0]]
])
print linear_transformation(M, M, f)
This is not working - but I can't figure out what linear_transformation is expecting.
How can I get this to work? Is this even possible?rlswMon, 05 Nov 2018 14:00:31 -0600http://ask.sagemath.org/question/44194/Finding the matrix of a linear affine transformation and its inversehttp://ask.sagemath.org/question/41629/finding-the-matrix-of-a-linear-affine-transformation-and-its-inverse/How do i get the matrix representation of an affine transformation and it's inverse in sage?
I am more so interested in doing this for random affine transformations as i am using them in a multivariate cryptography scheme but for example the following affine transformation over GF(3)
[1 0 0 2 0 2] [1]
[2 2 1 1 2 0] [1]
[2 0 0 2 2 2] [0]
x |-> [2 2 0 1 1 1] x + [1]
[1 0 2 0 2 0] [0]
[0 0 0 2 0 2] [2]DalvirMon, 19 Mar 2018 11:03:59 -0500http://ask.sagemath.org/question/41629/transformation to lines and circleshttp://ask.sagemath.org/question/35516/transformation-to-lines-and-circles/I'd like to take a circle and apply a transformation to it (such as a reflection or a translation).
For instance, if T1 is translation 1 unit right and
c1 = circle((0,0),1),
I'd like to be able to plot T1(c1) (the image of c1 under T1, which is the circle with new center (1,0)).
How can I do this? Daniel LThu, 10 Nov 2016 21:34:40 -0600http://ask.sagemath.org/question/35516/Echelon form of matrix with coefficients in Zphttp://ask.sagemath.org/question/25142/echelon-form-of-matrix-with-coefficients-in-zp/I was wondering if there was a way to find the echelon form of a matrix with coefficients in Zp with sage? I tried
<pre><code>Matrix(Zp(5), 3, 3, [1..9]).echelon_form()</code></pre>
but this gives a NotImplementedError as echelon_form is not implemented over generic non-exact rings at present. I would also very much like the transformation matrix used to get to echelon form if possible.hypercubeFri, 05 Dec 2014 10:10:06 -0600http://ask.sagemath.org/question/25142/Sage does not simplify trigonometric expresionhttp://ask.sagemath.org/question/24256/sage-does-not-simplify-trigonometric-expresion/Hello,
the sage does not simplify the expression
a(phi) = (1 - cos(phi)) / sin(phi)
to tan(phi/2)
what wolfram alpha does...
is this a bug or a feature??top mixTue, 23 Sep 2014 07:26:55 -0500http://ask.sagemath.org/question/24256/Birational Transformationhttp://ask.sagemath.org/question/10161/birational-transformation/How do I apply a birational transformation x --> 1/x, then clear the denominators. Is there a way I could do that in SAGE?
x, y = QQ['x,y'].gens()
C = Curve(x^2+y^2)
# the code I'm looking for here
$x^2 + y^2 \mapsto 1/x^2 + y^2 \mapsto 1/x^2 + x^2y^2/x^2 \mapsto 1 + x^2y^2$guissmoTue, 28 May 2013 05:16:57 -0500http://ask.sagemath.org/question/10161/