ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 01 Feb 2016 00:56:36 +0100How do you Append a Symbolic Matrix?https://ask.sagemath.org/question/32406/how-do-you-append-a-symbolic-matrix/To All:
I am trying to make a function that will take a set of dynamics and a set of independent variables that can or cannot be within the dynamics equations to create a "frozen" state space matrix, A. I would like to tell you all now that I am mostly a FORTRAN coder and am in the process of trying to understand SageMath, which is why I am coding in a brute force method.
I previously checked to make sure that the derivative function was producing reasonable answers and created the matrices like this.
rmag = r[0]^2 + r[1]^2 + r[2]^2;
dyn = -mu*r/rmag^3; # spherical gravity assumption
ddyn_dx = dyn.derivative(r[0]);ddyn_dy = dyn.derivative(r[1]);ddyn_dz = dyn.derivative(r[2]);
pdyn_pr = (transpose(matrix([ddyn_dx,ddyn_dy,ddyn_dz])));
As you might have discovered, this is exceptionally tedious when the number of independent variables get larger.
Therefore, I desired to code something like this:
def FindDynMatrix(dynamics,xvect):
# Find the length of the vector defining the internal variables
# within dynamics are independent variables:
leng = len(xvect);
for j in range(leng):
vect = dynamics.derivative(xvect[j]);
if j == 0:
mat = vect;
else:
mat=matrix([mat,vect])
#mat = mat.append(vect) # didn't work
return mat
In "FindDynMatrix", symbolic vector that is dependent on a multitude of variables including those within the symbolic vector "xvect". The hope was to "black box" the production of the A matrix for a little controls tool that I am coding up.
However, I can not find a way to get this to work. Help would be appreciated.
PleaseNoCyrillicVariablesMon, 01 Feb 2016 00:56:36 +0100https://ask.sagemath.org/question/32406/