Advanced Search

Question: A Maple 2015 bug

Question:A Maple 2015 bug

sand15 1374 Maple 2015
multiplication matrix vector
December 22 2025
2

This is a report of a Maple_2015's bug, apparently fixed in more recent versions, but which may have persisted for a few versions beyond 2015.
I don't think it's necessary to fill out an RCS form.

All started with an error in my code which was balanced by a maple 2015 bug. So I didn't see any error until I sent my code to @C_R  who uses a newer Maple version.
More precisely, in my Maple 2015 code I defined a NxN matrix B, a vector A of length N, that I mistakenly defined as a vector column, and finally computed the quantity R = A . B . A+.
Of course Maple should have fire an error.

The bug is that Maple 2015 doesn't fire an error if A is a float vector and B a float matrix.

> 

restart
> 

kernelopts(version)

`Maple 2015.2, APPLE UNIVERSAL OSX, Dec 20 2015, Build ID 1097895`

 (1)
> 

A := Vector(2, symbol=a):
B := Matrix(2$2, symbol=b):
R := A.B.A^+

Error, (in LinearAlgebra:-Multiply) cannot multiply a column Vector and a Matrix

  
> 

A := Vector(2, i -> i):
B := Matrix(2$2, (i, j) -> i+j):
R := A.B.A^+

Error, (in LinearAlgebra:-Multiply) cannot multiply a column Vector and a Matrix

  
> 

A := evalf(Vector(2, i -> i)):
B := evalf(Matrix(2$2, (i, j) -> i+j)):
R := A.B.A^+

30.

 (2)
> 

R := A^+.B.A

30.

 (3)
 

 

Download Maple_2015_Bug.mw
Please Wait...