Re: [Mathlib-develop] Re: Symbolic calculations

[mark <msp...@ya...>]

Hi

This is an overview of the state of the Symolic section.

When an expression containting a symbolic token is evaluated it returns a=
=20
symbolic expression. there are three types of SymbolicExpression dependin=
g on=20
the type of the operator

SymbolicExpression
=09ArithmaticSymbolicExpression
=09GeometricSymbolicExpression
=09ExponentialSymbolicExpression

When a function that contains either a SymbolicToken or a SymbolicExpress=
ion=20
is evaluated it returns itself.

ArithmaticSymbolicExpression stores an ArrayList of the operands and a nu=
meric=20
multiplier. So X + Y + Z is stored as a single ArithmaticSymbolicExpressi=
on.

GeometricSymbolicExpression stores an ArrayList of the numerator and=20
denominator as well as a numeric multiplier. So it can store expressions =
like=20
(U*V*W)/(X*Y)

ExponentialSymbolicExpression stores the mantissa and exponent.

At the moment the following functions work to varying degrees
Simplify(exp)
Expand(exp)
Derivative(exp, deriveBy)
Integral(exp, integrateBy)
Subst(exp, old, new)

The following doesn't work

Derivative for expressions of the form U^V
Derivatives only work for a small number of functions
The output from Derivative can be messy

Integrals for expressions of the form U*V, U/V, U^V and fn(U)

Factorization still doesn't work at all

Despite this I'd suggest removing the code for the meditor library since =
it's=20
not being used any more.

if there are any queries, comments or suggestions then let me know  =20

Best Regards

Mark

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