Contrib ODE vs integrate



> From: Raymond Toy
> 
> A while back, I changed integrate to fix the long-standing 
> integration 
> bug, integrate(sqrt(x+1/x-2),x,0,1).  The cause of this bug was in 
> intform where it set radexpand:all.  This caused maxima to convert 
> sqrt((x-1)^2) to x-1, when 1-x was really wanted.
> 
> However, I see this this change breaks a lot of tests in the 
> contrib ODE 
> package; that was not intentional.  At this point, I see a 
> few solutions.
> 
> o Revert the change, reinstating the old bug.

No.

> o Leave the change in and accept the failures in ODE
>   (and/or adjust ODE tests appropriately)

OK with me.  I've started on this by disabling tests that
fail so we have clean results.   I am sure that analysis of
the failures will find all sorts of bugs - some of them mine.

> o Add a new variable to allow the user to control what
>   value of radexpand will used in intform.
> o Change intform so it doesn't touch radexpand, so it uses
>   whatever the current value is.

The second option seems easier to implement.  I guess we set a safe
default and allow users to relax this if they have additional knowledge.

> I do not know if the last option will fix the ODE test 
> failures or not.

Don't care.


	David


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