Hi Peleg,
It would be better if matrix would do a type check for partial function.
Currently it does not, the relevant line is
{{{
if isinstance(arg, (types.FunctionType, types.LambdaType,
types.MethodType)):
}}}
in sage/matrix/constructor.pyx the function MatrixFactory.
Concerning a direct solution, you can cheat with
sage: matrix(QQ, 3, 3, lambda i,j: g(i,j))
Or even more directly with
sage: matrix(QQ, 3, 3, lambda i,j: f(i,j,7))
Vincent
Le 21/12/2016 à 13:29, Peleg Michaeli a écrit :
The matrix (or Matrix) documentation reads:
INPUT:
* "ring" -- the base ring for the entries of the matrix.
* "nrows" -- the number of rows in the matrix.
* "ncols" -- the number of columns in the matrix.
* "sparse" -- create a sparse matrix. This defaults to "True"
when the entries are given as a dictionary, otherwise defaults to
"False".
* "entries" -- see examples below.
However, the examples below do not give any example of using "entries"
as a *keyword
argument*. And, indeed, passing `entries=...` in the call of Matrix
raises
TypeError.
I can overcome this using positional arguments only. Here is a working
example:
sage: def f(i, j):
....: return i+j
....:
sage: matrix(QQ, 3, 3, f)
[0 1 2]
[1 2 3]
[2 3 4]
But if I am passing a *partial function*, this does not work any more:
sage: def f(i, j, x):
....: return (i + j) * x
....:
sage: import functools
sage: def f(i, j, x):
....: return (i + j) * x
....:
sage: g = functools.partial(f, x=7)
sage: g(0, 1)
7
sage: matrix(QQ, 3, 3, g)
Traceback (most recent call last):
File "<ipython-input-131-5bd380f06a54>", line 1, in <module>
matrix(QQ, Integer(3), Integer(3), g)
File "sage/matrix/constructor.pyx", line 794, in
sage.matrix.constructor.
MatrixFactory.__call__ (build/cythonized/sage/matrix/constructor.c:7154)
return MatrixSpace(ring, nrows, ncols, sparse=sparse)(entries)
File
"/home/peleg/sage/local/lib/python2.7/site-packages/sage/matrix/matrix_space.py"
, line 531, in __call__
return self.matrix(entries, coerce, copy)
File
"/home/peleg/sage/local/lib/python2.7/site-packages/sage/matrix/matrix_space.py"
, line 1488, in matrix
return MC(self, x, copy=copy, coerce=coerce)
File "sage/matrix/matrix_rational_dense.pyx", line 199, in
sage.matrix.
matrix_rational_dense.Matrix_rational_dense.__init__
(build/cythonized/sage/
matrix/matrix_rational_dense.c:4734)
raise TypeError("entries must be coercible to a list or integer")
TypeError: entries must be coercible to a list or integer
How can I make this work?
