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Submitted by : (unknown) at: 2007-11-17T22:09:02-08:00 (9 years ago)
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From
Vladimir Bondarenko Subject -- Axiom-developer AXIOM BUG: D(1, z) Date -- Mon, 17 Jan 2005 07:35:49 +0200

Hi *,

A terrible bug in differentiation.

axiom
D(sin(z)^2+cos(z)^2, z)

\label{eq1}0(1)
Type: Expression(Integer)
axiom
D(simplify(sin(z)^2+cos(z)^2), z)

\label{eq2}0(2)
Type: Expression(Integer)

BUT

axiom
D(1, z)
There are 5 exposed and 0 unexposed library operations named D having 2 argument(s) but none was determined to be applicable. Use HyperDoc Browse, or issue )display op D to learn more about the available operations. Perhaps package-calling the operation or using coercions on the arguments will allow you to apply the operation.
Cannot find a definition or applicable library operation named D with argument type(s) PositiveInteger Variable(z)
Perhaps you should use "@" to indicate the required return type, or "$" to specify which version of the function you need. D(cosh(z)^2-sinh(z)^2, z)

\label{eq3}0(3)
Type: Expression(Integer)
axiom
D(simplify(cosh(z)^2-sinh(z)^2), z)

\label{eq4}0(4)
Type: Expression(Integer)

wrong arument types
Mon, 17 Jan 2005 22:28:18 -0600 reply
D(1,z) is not a valid type signature. Try

axiom
D(1::Expression(Integer),z)

\label{eq5}0(5)
Type: Expression(Integer)

In Axiom it is important to know the type of the arguments to a function. In this case you gave the D function a PositveInteger? and is does not have a path to coerce PositiveInteger -> Expression(Integer).

Whenever you see the message about exposed and unexposed library functions the meaning is that you didn't match the type of the arguments and the interpreter couldn't get there from here.

The coercion/conversion tower in the interpreter is not well defined and sometimes it needs help.

Tim

property change
Mon, 17 Jan 2005 22:28:35 -0600 replyStatus: open => closed

Category: Axiom Mathematics => Axiom Interpreter




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