[Scilab-users] bug in degree and polynomials comparison ?

[philippe]

Hi,

while upgrading one of my toolboxes I discovered a strange error in
polynomial comparisons. The error appeared during automatic unit tests,
a " assert_checkequal(P1,P2)" was expected to be True and was in fact
False. After some investigations It looks like there is an error in
degree so that   P1==P2 can be False  while  P1-P2==0.

Can someone confirm the bug in scilab-6.0.1  before I fill in a report
on bugzilla. Run the following commands :

X=poly(0,'x')
A=(X-1)^3
B=(X+1)^2
R=20 +12*X
Q=(A-R*X^3)/B;
Q=Q.num

A,(B*Q+R*X^3) // equal
A-(B*Q+R*X^3)  //=0
A==(B*Q+R*X^3)  // %F !!!!
coeff((B*Q+R*X^3))
coeff(A)
degree((B*Q+R*X^3)) // =4 !!
degree(A)  // = 3

and compare with the expected result thereafter

Sincerly yours,

Philippe

--> A,B,Q,R
 A  =

            2   3
  -1 +3x -3x  +x

 B  =

           2
   1 +2x +x

 Q  =

             2
  -1 +5x -12x

 R  =


   20 +12x


--> A,(B*Q+R*X^3)
 A  =

            2   3
  -1 +3x -3x  +x

 ans  =

            2   3
  -1 +3x -3x  +x


--> A-(B*Q+R*X^3)
 ans  =


   0


--> A==(B*Q+R*X^3)
 ans  =

  F


--> coeff((B*Q+R*X^3))
 ans  =

  -1.   3.  -3.   1.   0.


--> coeff(A)
 ans  =

  -1.   3.  -3.   1.


--> degree((B*Q+R*X^3))
 ans  =

   4.


--> degree(A)
 ans  =

   3.