#14965: FloatingPoint exception when multiplying matrix over QQ by vector over
SR
-------------------------+-------------------------------------------------
Reporter: dkrenn | Owner:
Type: defect | Status: new
Priority: major | Milestone:
Component: linear | Keywords: matrix, vector,
algebra | mutliplication, floatingpoint exception
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Dependencies: | Stopgaps:
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The input
{{{
Z=1/3
def matrix_entry(s,r):
result = 0
result += Z^(s-r)
return result
A = matrix([[matrix_entry(s,r) for r in range(1,22)] for s in
range(1,22)])
v = vector([(2/3)^s+x*(2/3+4/9*(2/3)^30)^s for s in range(1,22)])
A*v
}}}
gives
{{{
Traceback (click to the left of this block for traceback)
...
RuntimeError: Floating point exception
}}}
Since the matrix has entries in {{{QQ}}} and the vector entries in the
symbolic ring, there should not be any floating point operations involved.
The example starts to work if you take smaller matrices or other entries.
--
Ticket URL: <http://trac.sagemath.org/ticket/14965>
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