tracker issue for non-Expr in matrices

[cbm755]

We have various issues stemming from upstream SymPy's decision (sensible decision, that is!) to not allow things that are not expressions into matrices.

Examples of things we do:

• True/False
• Equations/Inequalities: Eq(x, y) in Python
• None

I'll link issues / failing tests / etc to this Issue number.

TODO list

• failing test in isNone
• helper functions reworked to use list of lists during insertations
  • various rclist_mat* functions in @sym/private/
• could potentially revisit above later
• workaround eq: giving TypeError: cannot determine truth value of Relational #1055 by building matrices all-at-once form a preassembled list-of-lists.
  • consider using Array or other data structure for sym when there are non-Expr in them.

related issues

#1107, #1084, etc

upstream issues

• pretty print Array: uses Matrix code so Equality gives warnings sympy/sympy#23305
• main upstream tracker issue: Non-Expr objects in a Matrix are deprecated sympy/sympy#21497
  • (need to make sure that does not get closed before we have finished porting to some sort of replacement!)

[cbm755]

For 3.0.0, we don't need permanent fix (its only deprecated upstream), but of course would be nice...

[cbm755]

Alternatively if the goal is just printing support then perhaps TableForm can be used.

https://docs.sympy.org/latest/explanation/active-deprecations.html#deprecated-non-expr-in-matrix

@alexvong243f We should investigate whether TableForm would work instead of Array.

[alexvong243f]

From the doc-string of TableForm, the only documented way to extract the original data is to use as_matrix(), which is obviously not what we want. One can do it using the undocumented attribute of _lines though.

Help on class TableForm in module sympy.printing.tableform:

class TableForm(builtins.object)
 |  TableForm(data, **kwarg)
 |
 |  Create a nice table representation of data.
 |
 |  Examples
 |  ========
 |
 |  >>> from sympy import TableForm
 |  >>> t = TableForm([[5, 7], [4, 2], [10, 3]])
 |  >>> print(t)
 |  5  7
 |  4  2
 |  10 3
 |
 |  You can use the SymPy's printing system to produce tables in any
 |  format (ascii, latex, html, ...).
 |
 |  >>> print(t.as_latex())
 |  \begin{tabular}{l l}
 |  $5$ & $7$ \\
 |  $4$ & $2$ \\
 |  $10$ & $3$ \\
 |  \end{tabular}
 |
 |  Methods defined here:
 |
 |  __init__(self, data, **kwarg)
 |      Creates a TableForm.
 |
 |      Parameters:
 |
 |          data ...
 |                          2D data to be put into the table; data can be
 |                          given as a Matrix
 |
 |          headings ...
 |                          gives the labels for rows and columns:
 |
 |                          Can be a single argument that applies to both
 |                          dimensions:
 |
 |                              - None ... no labels
 |                              - "automatic" ... labels are 1, 2, 3, ...
 |
 |                          Can be a list of labels for rows and columns:
 |                          The labels for each dimension can be given
 |                          as None, "automatic", or [l1, l2, ...] e.g.
 |                          ["automatic", None] will number the rows
 |
 |                          [default: None]
 |
 |          alignments ...
 |                          alignment of the columns with:
 |
 |                              - "left" or "<"
 |                              - "center" or "^"
 |                              - "right" or ">"
 |
 |                          When given as a single value, the value is used for
 |                          all columns. The row headings (if given) will be
 |                          right justified unless an explicit alignment is
 |                          given for it and all other columns.
 |
 |                          [default: "left"]
 |
 |          formats ...
 |                          a list of format strings or functions that accept
 |                          3 arguments (entry, row number, col number) and
 |                          return a string for the table entry. (If a function
 |                          returns None then the _print method will be used.)
 |
 |          wipe_zeros ...
 |                          Do not show zeros in the table.
 |
 |                          [default: True]
 |
 |          pad ...
 |                          the string to use to indicate a missing value (e.g.
 |                          elements that are None or those that are missing
 |                          from the end of a row (i.e. any row that is shorter
 |                          than the rest is assumed to have missing values).
 |                          When None, nothing will be shown for values that
 |                          are missing from the end of a row; values that are
 |                          None, however, will be shown.
 |
 |                          [default: None]
 |
 |      Examples
 |      ========
 |
 |      >>> from sympy import TableForm, Symbol
 |      >>> TableForm([[5, 7], [4, 2], [10, 3]])
 |      5  7
 |      4  2
 |      10 3
 |      >>> TableForm([list('.'*i) for i in range(1, 4)], headings='automatic')
 |        | 1 2 3
 |      ---------
 |      1 | .
 |      2 | . .
 |      3 | . . .
 |      >>> TableForm([[Symbol('.'*(j if not i%2 else 1)) for i in range(3)]
 |      ...            for j in range(4)], alignments='rcl')
 |          .
 |        . . .
 |       .. . ..
 |      ... . ...
 |
 |  __repr__(self)
 |      Return repr(self).
 |
 |  __str__(self)
 |      Return str(self).
 |
 |  as_latex(self)
 |
 |  as_matrix(self)
 |      Returns the data of the table in Matrix form.
 |
 |      Examples
 |      ========
 |
 |      >>> from sympy import TableForm
 |      >>> t = TableForm([[5, 7], [4, 2], [10, 3]], headings='automatic')
 |      >>> t
 |        | 1  2
 |      --------
 |      1 | 5  7
 |      2 | 4  2
 |      3 | 10 3
 |      >>> t.as_matrix()
 |      Matrix([
 |      [ 5, 7],
 |      [ 4, 2],
 |      [10, 3]])
 |
 |  as_str(self)
 |
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |
 |  __dict__
 |      dictionary for instance variables (if defined)
 |
 |  __weakref__
 |      list of weak references to the object (if defined)

[alexvong243f]

Is putting non-Expr in Array officially supported? If not, using an undocumented attribute could be a less bad option going forward...