TODO list for the pynac interface
"fully get rid of maxima-based symbolic variables"
remaining items
- support for _fast_eval
- hash is random
- pyobject deallocations, memory leaks
- noncommutative symbols
- symbol domains (ginac supports real, complex, integer)
- precision for numeric evaluation (evalf, _mpfr_, William's list)
genuine coercions to real field, etc.
- pickling (William's list)
Support pickle via the "archive" print mode.
Maybe change SAGE's Ginac to make a call to a cython gcd function, then use
singular, since singular's gcd over QQ is much better than ginac's, I think,
and ginac *only* does GCD over QQ. Actually, just make everything in normal.cpp
be implemented via Singular, probably...
- unevaluated expressions?
- piecewise expressions, substitution and pattern matching
long term
- find a better scheme for handling compare()
in progress
- Arithmetic with infinity (almost done)
- Series expansions
done
Sage 3.3 - pynac-0.1.2
- symbolic binomial and factorial
- iterator for sage.symbolic.expression.Expression
- operator method
- (similar to current _operator(), but returns the function if the expression is a function application)
sage: var('x,y,z,n,i,j',ns=1)
(x, y, z, n, i, j)
sage: sin(x).operator()
sin
sage: type(sin(x).operator())
<class 'sage.calculus.calculus.Function_sin'>
sage: factorial(n).operator()
factorial
sage: type(factorial(n).operator())
<class 'sage.calculus.calculus.Function_factorial'>- evaluation
- Substitution for more than variable done, call semantics/syntax needs more thought
- print order (William's list)
This text was a part of William's original todo notes, perhaps now it's confusing to include it here.
Now,
sage: x^2 + x^4 + x^3
x^2 + x^3 + x^4
sage: a^3*x^10 + x^12 - a^15
x^12 + a^3*x^10 - a^15
So it is printing from lowest to highest degree, like mathematica (or power series),
but unlike the standard sage convention (or maple, singular, MATH, etc.):
sage: R.<a,x> = QQ[]
sage: a^3*x^10 + x^12 - a^15
-a^15 + a^3*x^10 + x^12
sage: singular(a^3*x^10 + x^12 - a^15)
-a^15+a^3*x^10+x^12
- collect_common_factors (William's list)
need to be able to do this (from ginsh):
> collect_common_factors(x/(x^2 + x));
(1+x)^(-1)
- pretty printing (latex() method, a/b instead of a*b^{-1}, etc.)
- callable symbolic expressions
