Trouble coercing a vector directly to a matrix

[jonhanke]

Vector to matrix coercion appears not to work unless going through a list.

sage: v = vector(QQ,[1,2,3])
sage: v
(1, 2, 3)
sage: type(v)
<type 'sage.modules.vector_rational_dense.Vector_rational_dense'>
sage: 
sage: Matrix(QQ, 3,1,v)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/Users/jonhanke/Documents/SAGE/sage-4.6/<ipython console> in <module>()

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python2.6/site-packages/sage/matrix/constructor.pyc in matrix(*args, **kwds)
    660             ring = rings.ZZ
    661             
--> 662     return matrix_space.MatrixSpace(ring, nrows, ncols, sparse=sparse)(entries)
    663         
    664 

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python2.6/site-packages/sage/matrix/matrix_space.pyc in __call__(self, entries, coerce, copy, rows)
    403             return self(entries.matrix(), copy=False)
    404 
--> 405         return self.matrix(entries, copy=copy, coerce=coerce, rows=rows)
    406 
    407     def change_ring(self, R):

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python2.6/site-packages/sage/matrix/matrix_space.pyc in matrix(self, x, coerce, copy, rows)
   1134                 x = new_x
   1135             
-> 1136         return self.__matrix_class(self, entries=x, copy=copy, coerce=coerce) 
   1137      
   1138     def matrix_space(self, nrows=None, ncols=None, sparse=False):

/Users/jonhanke/Documents/SAGE/sage-4.6/local/lib/python2.6/site-packages/sage/matrix/matrix_rational_dense.so in sage.matrix.matrix_rational_dense.Matrix_rational_dense.__init__ (sage/matrix/matrix_rational_dense.c:5774)()

TypeError: entries must be coercible to a list or integer
sage: Matrix(QQ, 3,1, list(v))
[1]
[2]
[3]
sage: 

CC: @williamstein @jonhanke

Component: linear algebra

Keywords: matrix, vector

Issue created by migration from https://trac.sagemath.org/ticket/10613

[rbeezer]

comment:1

If you leave out the dimensions (which would be inferred from the vector), it is possible to build a matrix from a vector.

sage: w=vector(QQ, [1,2,3])
sage: A = Matrix(QQ, w); A
[1 2 3]
sage: A.parent()
Full MatrixSpace of 1 by 3 dense matrices over Rational Field

[jdemeyer]

Changed author from Jonathan Hanke to none

[jdemeyer]

comment:6

Fixed in #24742