Version 174 (modified by 20 months ago) (diff)  ,

This page gives an overview of open symbolics issues. If you notice a symbolics or calculus issue that is not listed on this page, feel free to add it to the relevant section below.

 Other Symbolic pages
 Wikipedia links and some papers
 Links for these tickets
 Solve tickets
 Integration tickets
 simplify/expand tickets
 desolve tickets
 limit and summation tickets
 series() and taylor()
 limitations of Piecewise functions
 conversion to/from other rings
 fast_float deprecation
 performance
 expression tree and substitutions
 relation/equality, unknown results, tristate logic
 variable domains and assumptions
 specific Pynac/GiNaC issues
 Maxima interface
 SymPy interface
 Giac interface
 FriCAS interface
 Other
 Tickets fixed
Other Symbolic pages
 Symbolic functions
 wiki page to coordinate work on new symbolics functionality.
 symbolics/maxima dependencies on maxima
 symbolics/nonzero solving the zero comparison problem
 Pynac bugs are tracked in the github issue tracker.
 symbolics/switch_todo old TODO list for symbolics backend switch to pynac
Wikipedia links and some papers
 https://en.wikipedia.org/wiki/Symbolic_computation
 https://en.wikipedia.org/wiki/Expression_(mathematics)
 https://en.wikipedia.org/wiki/Richardson%27s_theorem
 https://en.wikipedia.org/wiki/Unification_(computer_science)
 Watt, Making computer algebra more symbolic
 Watt, What happened to languages for symbolic mathematical computation
Links for these tickets
 calculus or symbolics tickets tagged `needs_review`
 calculus or symbolics tickets tagged `needs_{work,info}`
 calculus or symbolics tickets still tagged `new`
Solve tickets
 Unsolved or wrongly solved expressions by type:
 univar. polynomial: #11941, #18900, #10311, #20436
 polynomial in sin(x),cos(x): #3745
 polynomial equation system: #6231, #15499, #9625
 poly fraction system: #15859
 polynomial plus sqrt: #14215
 poly fraction with trig. functions: #14628, #14736, #14738, #16593
 linear system with complicated coefficients: #21873
 exponential equation/system: #18006, #8862, #20068
 mixed system: #16753, #22149
 using conjugate: #18488
 polynomial inequality: #14229
 Spurious/missed solutions
 #2617  solve() can return undefined points as "solutions"
 #11941  Solve and assumptions too aggressive with cube root of negative numbers
 #18902  spurious results as inequality solution
 #20755  Bug in solve due to a bug in symbolic_expression_from_maxima_string
 #21939  Solving with respect to a dummy variable behaves wrong
 #24939  solve should not convert floating point to rationals when solving
 Enhancements
 Change defaults/interface
 #5679  solve should convert additional args to SR
 #6231  what to do with systems and multiplicities
 #10213  default
solution_dict
 #10750  additional args are not handled uniformly
 #14736  trig case where to_poly_solve True works, but not force
 #22018  Some debug(?) message when solving an inequality
 #23136  Allow giac algorithm in solve
 #23992  solve() doesn't solve some system solvable by (standalone) Maxima's solve()
 #24102  solve(....solution_dict=True) produces nonsense
 #24142  Improve interface to SymPy? solvers
 #24477  solve(x, [x], solution_dict=True) error
Integration tickets
 Bug, solved upstream
 Bug, not fixed yet upstream (indefinite/symbolic int)
 #15504  log(1+x)/x
 #15747  bus or segmentation fault in integral computation
 #17469  an integral that keeps haunting
 #18822  sqrt * sqrt
 #21057  Assumption ignored in indefinite integral computation
 #22138  Wrong Maxima integral result for even exponents
 #24008  exp(acos)
 #24117 
integrate(sqrt(14*sin(x)^2),x)
is wrong  #24316  sqrt(sin,cos...)
 #25636  ECL crash: x^{m/sqrt(a + b*x}(2  m))
abs_integrate
related errors (see #12731 for possibly disabling or raising warning always with it) #13097  integral of ln(1+4/5*sin(x))
 #11590 
sgn()
function (not reported upstream?)  #14591  cosh integral incorrect because of abs_integrate
 #17183  another abs_integrate error
 #17468  log(abs(sin())) problem
 #17511  abs(sin(x)) and abs(cos(x)) are flatout wrong
 #17910  unsolved piecewise integrals metaticket
 #23271  abs(sin(x)*cos(x))
 definite integrals
 #11164  sin(x)/x
 #11493  two different results with same numeric integral
 #11655  Maxima missing rectform simplification after integral()
 #12145
 #13718
 #14213
 #14274  GSL fail on simpler divergent integrals
 #14764  Let Mathematica free integration work with definite integrals
 #14976  integration with non symbolic bounds broken
 #15219  numerical integral of
f(x) = x
fails  #15496  Incorrect result for divergent integral
 #16788  segfault in numerical_integral()
 #16905  really long intervals for integration
 #17606  Calculation involving nintegral works with Sage 6.3 but not with Sage 6.4
 #18059  runaway 'unable to simplify to float approximation'
 #18599  sqrt(cot^{2})
 #18821  sqrt(cos)*sin
 #20467  stackoverflow in sin(k*x)/x*erf(x^{2})
 #21440  cos(2*pi*x)
 #22567  GSL: Unevaluated integrals to infinity have nonsense numeric value
 #22671  ((1+x)^{(1/5)}/(1x)).integrate(x,2.,3.)
 #22676  Different results from definite integral methods
 #24008  exponential integral of arccos
 #24587  integral(sqrt(1cos(x)), x, 0, 2*pi)
 Changing interface
 floats in integrals: #12152, #14821
 Other
simplify/expand tickets
 #10038  wrap Maxima's demoivre and exponentialize into some simplify*
 #10073  held variables aren't restored
 #10137  rewrite function for symbolic expressions
 #10268  add Ginac method to
simplify_rational
 #10552  more elementwise simplifications for symbolic matrices
 #13099  Add a loop argument to simplify_full
 #14608  Symbolic functions break the hash contract
 #17065  use Maxima's trigrat() in symbolic simplify
 #17066  simplify hypergeometric() when it's a polynomial
 #17737  wrap Maxima's factorial/gamma conversions/expansions
 #18697  evalf as soon as a FP number and no symbols are present
 #19995  full_simplify involving square root without success
 #20520  apply Maxima's simpsum in sum() and simplify*()
 #21307  Maxima crash:
TypeError
when simplifying factorial ratio  #21335  Extend normalize() and use it instead of Maxima in simplify_rational()
 #21574  simplify_log() does not
 #22027  Simplifying 0^{x} gives 0, with no assumptions on x
 #22467, #22495  simplify_hypergeometric bug
 #22607  Add reduce_trig() to applied "full simplify" methods
 #22621  Improve sqrt products simplification
 #22699  simplify arccos+arcsin when appropriate
 #23738  simplify_full() fails to simplify a log expression
 #24231  Maxima's demoivre() doesn't work with hyperbolic functions
desolve tickets
 #8616  get desolve to automatically deduce variables
 #9825  Maxima temporary variables from diffeq confuse Sage
 #11482  power series solutions
 #11653  ODE whose solution implies integration limits
 #14092  Error with supposedly normal DE problem
 #14877  number of initial conditions in desolve_system
 #16653  immediately get all integral/ODE solutions instead of asking for assumption
 #16793  assumption is not used
 #17739  enhance desolve output from separable ODEs
 #20068  Another diffeq question
 #21789  possible bug in boundary condition handling in Sage (not Maxima)
 #22849  Heaviside in numerical resolutions
limit and summation tickets
 #13269  indeterminate limit result
 #14677  Limit computation causes Sage to crash
 #15395  Wrong limit for sequence
 #16422  cancellation of two indefinite limits
 #17428  wrong limit in derivative
 #17553  substitute_function() can leave limits unevaluated
 #17709  Maxima limit() regression
 #17878  Wrong answer for a simple limit
 #17892  Sage cannot work with Maxima's symbolic limit
 #19203  hold for limit
 #20452  spurious limit computation
 #22700  add sympy limit examples
 #26060  another wrong Maxima limit that is correct in Sympy
series() and taylor()
 #6119  deprecate taylor() in favor of series()
 #9555  Series expansions at singularities don't work
 #12589  series yields wrong result
 #15830  extracting coefficient x1 out of symbolic series wrong
 #15854  series of x^{s}, when s is symbolic
 #17400  simplify_full returns odd result from symbolic series input
 #18500  coercion of Laurent series to SR
 #19149  Sister Celine's method for hypergeometric series
 #19997  advanced symbolic series of Order any expression
 #19998  missing operator in symbolic series
 #20090  implement asec/acsc series at infinity
 #20846  Maxima does not handle symbolic series
 #21899  Incorrect Series Expansions of zeta(s) around 1
 #22201  Further series speed improvements
limitations of Piecewise functions
 #11225  improve plotting
 #8994  convolution support
 See also the Maxima pw.mac package
conversion to/from other rings
 numpy objects: #8824
 vector: #16761, vectorvalued functions: #11180, #11807, #12302, #11507
 #12745  Coercion problem with Algebraic Real Field
 #14277  Equality of symbolic expressions inside matrix
 #14504  finite field coercion fails for extended fields
 #14602  Symbolic expression to number fields
 #17782  implement expression.polynomial(...,sparse=True)
 #17825  wrong/weird conversion from SR to
InfinityRing
 #18500  coercion of Laurent series to SR
 #19231  SR should not coerce into QQbar
 #20454  conversion from SR[] to SR
 #20812  derivative of integer wrt to variable in polynomial ring should belong to that ring, not symbolic ring
fast_float deprecation
 #5572  fast_callable improvements (including deprecating fast_float)
 #13559  fast_float yields infinity when Python does, but should handle bigger numbers
 #16899  Allow complex functions in implicit_plot
 #24536  find_local_maximum/minimum() fails with expressions containing complex numbers
performance
 #12786  solve_mod is horribly slow for linear systems
expression tree and substitutions
 #6480  .subs_expr() method doesn't work for argument of D derivative operator
 #9329  improve documentation of how to access parts of the expression tree
 #10169  Operands and Operator of symbolic expressions
 #12577  make _convert() public
 #14270  Remove function call syntax for symbolic expressions
 #15733  substitution in symbolic function fails with latex_name
 #17504  solve() breaks substitute_function()
 #17757  substitute_function with var argument
 #18396  Handle substitutions of partial sums and products
 #21071  substitution in denominator is skipped
 #21754  Held symbolic powers cannot be approximated numerically
 #21758  Hold symbolic powers unevaluated if evaluation fails
 #22102  Substitutions inside piecewise functions don't work
 #22401  Let substitute_function handle anon functions explicitly
 #22926  Symbolic has_operator()
 #23304  hold=True does not always prevent evaluation
 #23964  f.subs(I==...) does not work
 #24255  Warn with substitution of derived classes using equality
 #24283  Implement Expression.has_function(...)
 #24428  Substitution should be the same as numerical evaluation
relation/equality, unknown results, tristate logic
 #7660  arithmetic with equations and inequalities confusing
 #12554  Adding a "swap" method to equation objects
 #17700  wrong symbolic results in case the answer is not known
 #11613 
RealInterval
expression comparisons broken  #18259  comparison of symbolic functions
 #19040  defuse bool(x!=0) performance bomb
 #19162  symbolic relations metaticket
 #20127  test_relation: uncaught
NoConvergence
 #20784  not all symbolic equations stay unevaluated
 #21070  comparison with wildcard raises error
 #21862  Symbolic methods work inconsistently on relational expressions
 #24658  Don't call Maxima with novariable symbolic relation tests
variable domains and assumptions
 #3277  context for calculus assumptions
 #6862  Mixing of different domains for symbolic variables
 #11941  Solve and assumptions too aggressive with cube root of negative numbers
 #18745  implement forgetting of assumptions on specific expressions
 #18999  basic assumptions on symbolic functions
 #19670  Consistency and redundancy of verbal assumptions
 #20132  add symbolic domains posint, crational
 #21981  Assuming a variable is prime
 #22022  floor of real x should be known to be at most x
 #22025  minus of real x should be known to be at most abs(x)
 #22162  Return Unknown from ex.is_xyz() if Pynac returns false
 #24351  Even assumption / variable domain / query
 #24352  Implement Expression.is_nonzero(); apply to ex.nonzero()
 #24368  Rational assumption / variable domain / query
 #24392  strange handling of variables in assume
 #28538  Segfault for boolean evaluation of expression with assumptions
specific Pynac/GiNaC issues
 #6756  Implement
diff
format symbolic derivative in new symbolics  #10069  Typesetting with hold=True can be weird
 #10268  add Ginac method to
simplify_rational
 #11428  customizable latex for GiNaC functions
 #11576  generate sequences of variables
 #12589  series yields wrong result
 #18630  Expression.is_positive/negative incomplete
 #18697  any FP number in an Expression without symbol should trigger evaluation
 #20824  Expression.coefficient() problems
 #21009  Fix symbolic GCD to accept any expression
 #21071  substitution in denominator is skipped
 #21758  Hold symbolic powers unevaluated if evaluation fails
 #22435  Random build failure in pynac
 #23304  hold=True does not always prevent evaluation
 #23368  More immediate symbolic powers simplification
 #23964  f.subs(I==...) does not work
 #24211  Some trivial identities and simplifications missed by Sage (pynac ?)
Maxima interface
 #6862  Maxima default domain is real, not complex
 #9825  interpret Maxima's temporary variables
 #11651  Decide what to do with e^{(y=x)}
 #12032  Symbolics code passes ungrammatical expressions to maxima
 #12809  Solve does not give consistent results when a dummy variable is involved
 #13071  maxima interface integration problem
 #13773  Translate maxima's if() function to Sage's cases()
 #16335  dictionary of symbolic expressions (functions) raises Maximaerror
 #17892  Sage cannot work with Maxima's symbolic limit
 #19151  expression manipulations that do not preserve function latex_name and print_latex_func
 #19909  segmentation fault: symbolic sum containing real
 #20221  Wrap ratsubst
 #20755  Bug in solve due to a bug in symbolic_expression_from_maxima_string
 #20846  Maxima does not handle symbolic series
 #21444  SR.wild and maxima don't mix
 #21907  Bug in Maxima interface wrt polylog
 #21974  Assuming x==0, x^{x} raises a noninformative error from Maxima
 #22027  Simplifying 0^{x} gives 0, with no assumptions on x
 #22763  Assumptions on symbols not preserved with some unevaluated integrals
 #22850  Change specific heaviside() interface to Maxima
 #22857  Using symbolic variables in domain 'positive' makes Sage crash
 #23138  Cache assumptions and only send to Maxima when needed
 #23328  Undefined limit product $INF * $ZEROB in limtimes
SymPy interface
 #16816  support SymPy's sum of roots
 #21412  Convert piecewise functions to SymPy
 #22700  Add more sympy limit examples
 #24078  Set assumptions in SymPy too when doing assume()
 #24142  Improve interface to SymPy? solvers
 #24334  sympy symbol > SR drops assumptions
Giac interface
 #23015  Convert rootof function from giac
 #23016  Dirac delta derivative conversion from giac
 #23136  Allow giac algorithm in solve
FriCAS interface
 #28630  Wrong conversion from fricas
Other
 #11210  add residues
 #17559  Incorrect caching of variables' latex_name attribute
 #17958  implement declare_var
 #18081  Expression.factor_list() result inconsistent
 #18092  evaluating symbolic expressions within ring of values
 #19046  Fix mma free algorithm when no answer
 #19093  bug in units conversion
 #20411  Injecting shorthands for the most usual units
 #20859  Simplify the logic handling the
EvaluationMethods
mixin class for Expression  #21067  Symbolic factor_list() should do integer factorisation of integers/rationals
 #22055  implement Remez algorithm
 #22393  sage_input for SR
 #22813  Pass number of variables to var
 #23332  Calculating eigenvectors of symbolic matrices leads to a crash.
 #24537  Make find_local_maximum/minimum() handle symbolic functions
 #24850  Provide convenient Expression.convert_numeric()
Tickets fixed
 #24800  bug with a system involving square roots, apparently do to an interface issue, Sage not being able to parse conditional answer provided by Maxima
 #24425  Fix inherently failing random_expr doctest
 #24440  Infinite loop from proving an expression
 #24773  Delayed/Conditional? Substitution
 #5574  taking symbolic powers should coerce objects to symbolic expressions
 #24418  bug numerical_approx(2^{(450232897/4888643760)) }
 #23545  segmentation fault with coefficients() on symbolic expressions
 #23845  Doctest improvements to symbolic GCD
 #24236  Structural comparison of expressions
 #24028  Held definite integrals don't translate to SymPy
 #17935  recognize SymPy's
NonElementaryIntegral
 #22322  allow sympy algorithm in solve
 #18787  Mod numbers are ignored
 #22071  Expression._latex_() triggers “dangerous” comparisons
 #23224  wrong symbolic comparison of log
 #24147  Segfault with ex.coefficients
 #17565  ugly LaTeX of unevaluated sums
 #8603  fix Fourier transforms of piecewise
 #17935  recognize Sympy's
NonElementaryIntegral
 #5091  find_root should call fast_float
 #11332  65x penalty in performance for using float instead of
RealNumber
 #16801  Not all sympy function results get translated to Sage
 #22566  SymPy's ceiling() is not translated to Sage
 #23923  Interface cases function with SymPy's piecewise
 #10035  Create hold context
 #18970  always simplify log(a^{m},a) to m for any a,m coercible to Integer
 #21391  Disallow mixing of pos.char.ring elements and symbolic variables
 #20204  problems with constructing or converting to SymPy expressions
 #14305  Clarify assumptions and domains in Maxima
 #23793  Bug in symbolic GCD computations involving complex I
 #23861  Make Expression normalization work with symbolic powers
 #22525  Improper expressions from SR(string)
 #15298  two copies of I
 #19996  wrong result extracting symbolic coefficient (rational exponent)
 #21973  is_negative() is False when assuming x < 0
 #22155  Add more logic flags to more functions
 #23135  Conjugate does not distribute over a sum
 #23496  sympy patch for abstract function
 #22709  to_poly_solve=True actually raises exception
 #17968  exp(x^{3}) from 1 to 2
 #22672  Definite integral of (1x)^{(1/5)}/sqrt(x) crashes with both GSL and Maxima
 #22915  Distribute symbolic sums over the terms of their first (sum) argument
 #22733  Bug with first call to ex.series()
 #20179  add a free_variables() method
 #22026  Even reals are integers
 #22894  Symbolic expression.is_exact()
 #22005  sum(1/((2*n+1)^{2}4)^{2}, n, 0, oo, algorithm='maxima') is wrong
 #20084  residue: mathematically wrong output
 #22833  fix a calculus doctest (giac, laplace, integration)
 #22909  Indexed SR variables
 #22706  Add more conversions from giac
 #22995  Dummy inverse Laplace for giac
 #22997  Parse unevaluated integral from giac
 #13733  integration (but note unwanted interactions)
 #22937  Implement a "distribute" method
 #21801  Maxima summation bug
 #22959  series() yields wrong result depending on precision
 #22090  Gosper algorithm
 #22422  Laplace transform involving timeshifts
 #22641  Fix integration with Mathematica online
 #22891  Add giac interface to integrate
 #22057  Resultant of symbolic polynomials
 #22174  Interface expression conversion to gamma() and normalization
 #22017 Unreadable real solution for a very simple equation
 #20162  properties of converted finite field elements are wrong
 #10284  Infinite loop in gcd() via pynac0.2.1
 #20089  let pynac.pyx use mpmath for arccos
 #20455  rewrite buggy Expression.coefficients() without Maxima
 #15605  (1)^{(2/3)} evaluates to 1
 #21428  AssertionError? plotting real part of complex function with float coefficients
 #14878  very slow taylor expansion for composite functions
 #21730  Add dedicated symbolic series tests
 #21223  SymmetricFunctions? over SymbolicRing? broken
 #16724  simplify_rational() takes very long or forever
 #20752  Wrong simplification in symbolic trigonometry involving fractions
 #20858  Option to combine symbolic fractions recursively
 #19775  normalization in Pynac buggy
 #20888  Support GinacFunction?._print_latex_() customization
 #21007  Unhelpful error when conversion to Symbolic Ring fails
 #10034  simplify_trig of f(a/b*pi) without Maxima
 #19464  ExpressionTreeWalker? fails on some functions
 #20456  assume(x>0) sets integer flag
 #16491  unify output of trigonometric functions for complex input
 #14801  Improved piecewise functions
 #9424  numerically evaluate sums (also in functions page)
 #16397  symbolic cmp, stopgap #19465
 #16203  conversion from SR.series() to PowerSeries?(SR) gives unexpected result
 #15451  limit wrongly gives ZeroDivisionError?
 #17402  SR.power_series cannot handle symbolic series
 #18094  multiplication of powerseries wrapped in SR wrong
 #19259  subrings of the symbolic ring
 #17659  factor out SymbolicSeries? from Expression
 #12967  comparison of pi and infinity wrong
 #19035  sync elementary assumptions on symbols/functions with Pynac
 #19310  Pynac hashes are restricted to 32 bits
 #17624  Coerce factorization of polynomial to symbolic expression
 #14211  Crash in GiNaC::Number_T::hash()
 #10048  deprecate substitute_expression()
 #12588  abs(pi*I) should return pi
 #18921  integer variable domain
 #18568  wrong expansion of (x+sqrt(2)*x)^{2 }
 #18695  propagate the variable domain to the assumptions database
 #17321  Pynac RuntimeError?: comparing typeid's
 #12257  1.0*pi should *not* be pi
 #18482  Unicode art for symbolics
 #15304  is_polynomial() returns wrong results
 #14326  Substituting numeric one in symbolic expression gives symbolic one
 #18257  fix symbolic/pynac.pyx doctests
 #17759  convenience class symbolic ExpressionTreeWalker?(Converter)
 #17849  substitute_function should not evaluate expression
 #18255  Remove silly LimitedPrecisionConstant? class
 #18088  Inconsistency with 0^{0 }
 #13326  Bug in comparisons of infinite values
 #12807  Taking the real part of a sum of exponentials ...
 #17394  TypeError? in Expression.simplify_hypergeometric()
 #15355  representation of CIFelement plus SRelement
 #8949, #9769  numpy object handling
 #15047  LaTeX typeseting of SR.wild should prefix $ with \
 #18084  Fix bad library uses of var()
 #18054  Add is_finite method for the Symbolic Ring
 #18040  Minimal polynomials of matrices over SymbolicRing?
 #10846  Conversion of PowerSeries? > SR bug
 #17799  refactor
real_set.RealInterval
 #9427  fricas integrator
 #3021  add curl and divergence functions to vectors
 #16643 integrate() infinite loop
 #15346  implement simplify_sum and call it from full_simplify
 #15571  Incorrect zero test of complex symbolic expressions
 #10629  performance of checking if (c/d)^{(a/b)} is rational
 #12922  add implicit derivative
 #9824  improve desolve system documentation for initial conditions
 #14630  add
simplify_real
 #16201  default precision for symbolic power series from SR.series()
 #16213  SR.series should simplify its terms
 #17399  fix coefficients for symbolic series
 #8969 
!=
in inputting and outputting with Maxima not handled right  #10444  make solve documentation better
 #13286  special case of one variable, one equation, variable in list
 #10914  Integral bug
 #11233  Integral bug
 #11445  Integral bug
 #11238  Integral bug
 #11656  additional assumptions needed for simplification
 #16941  Add a hold parameter for symbolic integrals
 #9908  a sum returns hypergeometric functions (also in functions page)
 #11894  about an infinite sum appearing on NMBRTHRY list.
 #12708  waiting for new upstream (Maxima) release.
 #13712  wrong result from infinite sum (Maxima bug).
 #13526 simple incorrect limit
 #9421  if
c
is already a variable it shouldn't come out as a constant  #16007  give solution constants of ODEs unique names
 #11785  simplifying complex exponentials needs
rectform
 #12322  invalid simplification of complex logarithm
 #14306 regression in solve
 #3520 
simplify_radical
does weird things  #11912  clarify and rename
simplify_radical
 #21940  Positive raised by a positive power is not known to be real
 #21946  solve(x==x, x) returns [x == r1]
 #1773  piecewise and symbolic don't play well together
 #12123  another convolution bug
 #24726  Sage silently accepts symbolic expressions with two comparison operators
 #23417  fast construction of symbolic sums
 #24768  Powers of symbolic sums inconsistence
 #23313  Add more conversions from giac II
 #23835  Replace Maxima with Pynac/Singular? in Expression.factor()