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2013-05-13 12:36:49 -0600 answered a question Problem with conjugate_transpose of a symbolic matrix

Sorry, Ta was a typo and should not be there. I used

dAbar = dAbar.dense_matrix()

and all is good. Thanks so much tmonteil.

nonlinear

2013-05-12 15:56:25 -0600 answered a question Problem with conjugate_transpose of a symbolic matrix
var('t,x3')
p1= -3+2.5*tanh(2.*t)+(3.19*sech(x3)-2.69)*I
p2= -3+2.5*tanh(2.*t)-(3.19*sech(x3)-2.69)*I
p3=-4
diagAbar= diagonal_matrix(Ta.[p1,p2,p3])
dAbar=diagAbar.subs(t=0);dAbar

Playing around with dAbar I found that:

TdiagAbar=dAbar.conjugate()

works, but

TdiagAbar=dAbar.transpose()

and

TdiagAbar=dAbar.conjugate()+dAbar

do not work. Sorry, I didn't follow much of what link said. I do a lot of symbolic math with symbolic variables such as with t and x3 above. I know MATLAB well and Mathematica somewhat. I would prefer to support Sage. Thanks for your help.

nonlinear

2013-05-11 16:46:41 -0600 asked a question Problem with conjugate_transpose of a symbolic matrix
dAbar=diagAbar.subs(t=0);dAbar          
[ 3.18953143618644*I*sech(x3) - 3.00000000000000 - 2.68953143618644*I   
0                                                                    0]
[                                                                   0
-3.18953143618644*I*sech(x3) - 3.00000000000000 + 2.68953143618644*I    
0]

[                                                                   0   
0                                                                   -4]

TdiagAbar=dAbar.conjugate_transpose() + dAbar

Traceback (click to the left of this block for traceback)
...
AttributeError:
'sage.rings.complex_interval.ComplexIntervalFieldElement' object has no
attribute 'sech'

I hope their is an easy answer. Thanks, nonlinear

2013-05-06 19:18:24 -0600 asked a question adjoint() does not work with trig functions.

adjoint() works for symbolic matrices except for those that have trig functions such as tan, sec, or tanh in their entries. Is there an easy way around this or do I need to create my own ajdoint() function? Thanks much.

nonlinear

2013-05-06 19:08:09 -0600 answered a question Conversion of Differential Forms to a manipulable symbolic expression

Thanks much. However, I have found a better way as follows:

sage: t, x3, dx3 = var('t x3 dx3')
sage: a = matrix([[x3+t,2,x3],[t^2,5,x3],[t,x3,x3^2]])
sage: b = derivative(a,t); b
[  1   0   0]
[2*t   0   0]
[  1   0   0]
sage: c = derivative(a,x3); c
[   1    0    1]
[   0    0    1]
[   0    1 2*x3]
sage: d = b+dx3*c; d
[ dx3 + 1        0      dx3]
[     2*t        0      dx3]
[       1      dx3 2*dx3*x3]
2013-05-04 16:04:16 -0600 asked a question Conversion of Differential Forms to a manipulable symbolic expression

[Sage 5.4.1] Hi, I got the following code that does total differentiation off a Sage blog:

sage: x, y, z = var('x, y, z')
sage: U = CoordinatePatch((x, y, z))
sage: F = DifferentialForms(U)
sage: f = F(x^2 + y + sin(z)); f
(x^2 + y + sin(z))
sage: g = f.diff(); g
cos(z)*dz + 2*x*dx + dy

How do I convert g to a symbolic form where dx, dy, and dz are also symbolic variables? I need to assign values to all variables via a for loop. Also, is it possible for g to be a 3x3 matrix? Thanks much, mahlon

2012-11-30 17:39:31 -0600 commented answer creating a matrix from blocks

Thanks much, but I still get a syntax error. I have double checked the matrices A,B,C,D, and E by using print and dimensions are correct. The matrices do contain symbolic variables that have been defined using var. Any suggestions? Thanks.

2012-11-30 13:16:53 -0600 answered a question creating a matrix from blocks

Thanks much, but I still get a syntax error. I have double checked the matrices A,B,C,D, and E by using print and dimensions are correct. The matrices do contain symbolic variables that have been defined using var. Any suggestions? Thanks.

2012-11-29 18:27:49 -0600 received badge  Student (source)
2012-11-29 12:30:58 -0600 asked a question creating a matrix from blocks

I am new to SAGE. I need to create a matrix by using matrices of different sizes. For example:

Abar= [(A + B), C]
      [  D ,    E]

where A and B are 2x2's, C is a 2x1, D is a 1x2, and E is a 1x1. I do not need Abar to be a partitioned matrix. Thanks much.