Hi Lucy,
Running on master I get this:
In [13]: sym.BlockMatrix([[a], [phi], [theta]])
Out[13]:
⎡⎡0⎤⎤
⎢⎢ ⎥⎥
⎢⎢0⎥⎥
⎢⎢ ⎥⎥
⎢⎣0⎦⎥
⎢ ⎥
⎢ φ ⎥
⎢ ⎥
⎣ θ ⎦
In [14]: sym.BlockMatrix([[a], [phi], [theta]]).shape
Out[14]: (11, 1)
Note that I've used extra square brackets to indicate that I want
these combined column-wise. Without those I get:
In [11]: sym.BlockMatrix([a, phi, theta])
Out[11]:
⎡⎡0⎤ ⎤
⎢⎢ ⎥ ⎥
⎢⎢0⎥ φ θ⎥
⎢⎢ ⎥ ⎥
⎣⎣0⎦ ⎦
In [12]: sym.BlockMatrix([a, phi, theta]).shape
Out[12]: (3, 3)
It's unfortunate that the sizes aren't checked there since those are
inconsistent.
It looks like the main problem you're having is fixed in master. What
version of SymPy are you using?
--
Oscar
On Wed, 19 Jun 2019 at 15:15, Lucy Jackson <lucy.jackson....@gmail.com> wrote:
>
> Hi,
>
> I am looking to concatenate three matrices (shown below) using BlockMatrix,
> however, the output has the wrong dimensions.
>
> theta = sym.MatrixSymbol('theta', 5, 1)
> phi = sym.MatrixSymbol('phi', 3, 1)
> a = sym.Matrix([[0],[0],[0]])
>
> X = sym.BlockMatrix([a, phi, theta])
>
> With this code I get the following output:
>
> X = Matrix([
>
> [ 0],
> [ 0],
> [ 0],
> [ phi[0, 0]],
> [theta[0, 0]]])
>
>
> However, I am expecting an output thats 11 x 1. I am also unable to check the
> shape of X as X.shape yields the following error:
>
>
> AttributeError: 'Zero' object has no attribute 'shape'
>
>
> Any help would be greatly appreciated!
>
>
> Many Thanks,
>
>
> Lucy
>
>
>
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