future plans:
-------------
* function investigation: intervals of monotonicity, convexity
    and concavity
* vylepsit zobrazeni celeho retezce funkci, pres ktere prochazime u
  transformaci grafu zakl el. fci (u PDF  animace). 
* Definicni obor funkci jedne promenne - upravit na vystup do PDF.
* Definicni obor funkci dvou promennych - upravit na vystup do PDF, vystup 
  do html nechat jako jednu z voleb.
* test, jestli jsou v urcitych integralech meze konstanty (a ne napr."exp")
* use a string variables for formconv executable 
* integral: if function can be splitted into sum and is in x variable,
   we can investigate terms separately. Allow this feature also for
   general variable (by converting into x variable first)
* think on Windows port (running in cygwin)

changes from January 2008
-------------------------

Some changes are motivatied by error messages from logs. It may
hapen that the problem which caused an error works well after few 
days. 

june 2010
* /usr/bin/timeout replaced by custom variable $mawtimeout to avoid
  conflict with another program /usr/bin/timeout from Debian distro

april 2010
* fixed bug
http://sourceforge.net/tracker/?func=detail&aid=2982092&group_id=221048&atid=1052162
* Catalan translation, thanks to Marti Ruiz-Altaba
* Changed repo into Mercurial, removed MAW releases and replaced by a script 
  which downloads the sources automatically and takes care about some more things.
* All po files in one directory now.
* Created mirror for sources at http://bitbucket.org/robert.marik/maw and
  http://bitbucket.org/robert.marik/maw-html. Primary repository is still
  sourceforge.net
* French translation, thanks to Marti Ruiz-Altaba again
* Autodetecting user's language
* Fixing inconsistency in notation when solving IVP for second order LDE 
  (non-mathematical bug)

february 2010
* Polish translation, thanks to Przemyslaw Dabek

october 2009 
* derivatives: test a#b replaced by fullratsimp(a-b)#0 --- fix for 
       sqrt(x**2+y**2)/y+y**4/4+x**2*y/2-y**3/2*sqrt((x/y)**2+1)+1/2*x*sqrt(x**2+y**2)
* graphs: strict policy which disallows to biuld more than one animation on
       the server at given time

july 2009
* autonomous systems: print eigenvalues when looking for stationary point
* developement frozen till September ---- hollidays :)

june 2009
* minor fix for LDE like y''+2.5*y'=exp(-x) ... coefficients passed to radcan first

may 2009
* the name of maxima executable is in a PHP variable. This allows to
  switch between diferent maxima versions easily
* ODE: added support for exact equations
* ODE: changed behavior: the expression from the second field 
  is passed to formconv and Maxima solver and solved with respect to y'.
  If the solution is unique, the result is passed to stepwise solver
  automatically.  
* minmax3d: added more simplifications to derivatives and improved test 
  if a point is stationary point: (1-sqrt(6),0) has not been reported as
  stationary point of y**3+y*x**2-2*x*y-5*y

april 2009
* domains of functions: reversed order of inequalities and fixed solve command
* fixed derivative of some complicated expression with quotient, 
    like x*%e**(-1/(x+2))/(x+2)**(2)+x*%e**(-1/(x+2))
* fixed derivatives like x^(exp(x))
* double integral: Numerical evaluation when chekcking region. 
    Fix for  integral of exp(y), y=0..log(9), x=exp(y)..9, dx dy
* graphs: fix for functions like 4^(-x)  ... these functions are
    automatically converted into 1/4^x by default in Maxima
* lde2: split rhs like x+exp(x)*sin(x)+exp(x)*cos(x) into two (not
   three) right hand sides when doing undetermined coefficients. Also
   supporting right han sides like sin(x)*cos(x)^6 thru trigreduce.

march 2009
* domains: ratprint:false   - solves the problem related to domain of
      1/3*log(x**3-1+sqrt(x**6-2*x**3))

february 2009
* integral: handle problem even if the user enters 
      "integral(function,x)" 
* all: computations are refused, if the server load is large
* offline version (VMware)
* domains: Maxima 5.17 is used to parse the expression. Model example 
    is sqrt(x^2+y^2-4) - Maxima 5.13 session failed.
    Thanks to Simona Fisnarova.
* derivatives: no simplifications if %i appears in the reslut. 
   Model  example for the problem is sqrt(1-x^2)+sqrt(x^2-1). 
   Thanks to David Kvapil.

january 2009
* integral: improved messages when doing substitution tan(x/2)=t and
     tan(x)=t
* integral: most TeX strings are generated by Maxima to avoid too many
    calls of formconv (which is still used heavily)
* autsyst: fixed the case with double root of characteristic equation
* integral: fixed broken trigsimp in integral with respect to y (x is
     constant)
* geom. application of integral: added float wrapper for bounds for
     integration using quadpack and fixed gettext call in geom.pl file 
     (there was a problem with integration on the interval like 1..e^3)
* ode: fixed missing brace for equations with integrating factor
* function ivestigations: evaluation of y'' preceedes solving y'=0 
     (and hence y'' is evaluated even if y'=0 fails for some reason)
* integral - geom: test that the lower limit which defines a region in the 
     plane is smaller than uppe limit
* ode: fixed solve command for ODE's. 
     y'=y*log(y) does not have constant solution y=0, but y=0 is one of results  
     of maxima command solve(y*log(y),y)

december 2008
* integral2: improved test that radial variable in polar coordinates is nonegative
* trapeziodal: added float around limits for numerical integration 
    (the limits could be something like %e^2)
* changed behavior related to jacobian in double integral and inititated
    support for internalizations and gettext
* highlighting errors and fixed error messages
* shifting graph - added partfrac to handle functions (ax+b)/(cx+d)

november 2008
* autsyst: parameters allowed only when evaluating stationary points. 
      (we get false error message about zero jacobian)
* autsyts: the type of stationary point is printed out and some
      details to the solution were added
* domains: no complex numbers in the solution of an algebraic equations

october 2008
* trapeziodal: romberg replaced by quad_qags. 
  (Romberg has problem with convergence if integral is exactly zero)
* ode: homogeneous: check that the "constant solution" does not depend on z=y/x
  (problem was for y'= (y*%e^(x/y)-x)/x )
* graph: no animation is created, if server load in last minute is
    bigger than 2 
* minmax3d: check that the stationary point does not contains %r1 etc.
    like for the function x*x*(x*(%e**(-x*x-y*y)))
* integral: if we integrate all terms in a sum, we use map command, this makes 
    integaration of 2/(x^2+1)-1/(x+1)+1/(x-1) simpler, namely 
     -log(x+1)+2*atan(x)+log(x-1) instead of 4*(-log(x+1)/4+atan(x)/2+log(x-1)/4)
* integral: removed radcan before the function is integrated. This allows to evaluate 
    integral of 1/(sqrt(1-x^2)*acos(x)^3) in the form involving acos(x)^(-2).
    The integral of 1/(sqrt(1-x)*sqrt(1+x)*acos(x)^3) involves atan2 and a warning 
    is produced in this case.
* trapezoidal: if scaling in y for the picture is too large, metapost gives error 
   (arithmetic overflow) and hence we draw no picture in this case. This concenrs 
   functions like  1/(x^3+125) on the interval from 0 to 1
* trapezoidal: x coordinates for picture are translated into decimal numbers. this 
   solves the problem with integration from 1e-10 to ....
* geom: no parameters are allowed
* all: detailed error message if greek letter is used instead of pi or %pi on input

september 2008
* banach: nonliner equations using bisection and iterations, variable y is not alloed
* all: sinh, cosh, tanh, coth, .....  on blacklist
* fixed bug in second order ODE's: if decimals are used and if D is 0.0, 
   then D=0 is false

august 2008
* lde2: support for right hand  sides like x+exp(-2x)*sin(x)+cos(2x)   
    (sum of quazipolynomials)
* functions investigation: no factorization if the derivative is number
* integral: support for output into PDF, definite integral, automatical
     back substitution
* double integral: link to swap inside limits, if these limits are
    interchanged and error is generated
* TeX files (maw.tex): \rihgtskip is 0 pt plus 1 fill
* derivative: use power rule for derivative of 1/(sin(x)*cos(x) - 
    not qoutitent rule
* fixed bugs in javascripts in animations produced by transformation of graph

31.7.
* formconv upgraded to last CVS version (solved problems with
  conversion of -(2/sqrt(x)) into TeX)

29.7.
* double integral: added trigsimp if the input contains trigonometric functions
* derivative: added support for derivative of absolute value

28.7.
* integral hints cover R(sin(ax+b),cos(ax+b)) and many other patterns
  (composite functions with powers)

26.7.
* history contains links which show the result of the computation

25.7.
* updated to maxima-5.15.0 (compiled sources) with clisp (sid) and back to 5.13.0 
  (better perfomance)

21.7.
* gnuplot does not evaluate sqrt(x) fox negative x. Hence the graph of
  sqrt(x)*sqrt(x-1) is on the interval (1,infty) only (and not on the
  union with the interval (-infty,0)).

19.7.
* integral called from PDF files (ODE, definite integral): formconv is
   on as default
* test that the degree of Taylor polynomial is an integer (small than
   10) and the center is not a funcito nof x.
* trapezoidal rule: test that the number of subintervals is a number
   between 0 and 20.

18.7.
* geometrical applications of definite integral: if the region is outside 
   the bounds for the picture, the bounds are changed

17.7.
* double integral - picture for domain of integration

16.7.
* double integral - added links from integrals in PDF to integral
   assistant, made necessary changes in integral assistant
* all files - removed hardwired paths nad URLs, fixed bug with missing
   $mpost variable
* trapezoidal rule and geometrical applications: definite integral is
   evaluated using Newton Leibniz formula (model example
   for the problem is integrate(log(x^2+1),x,0,1) which fails as a
   definite integral in Maxima, but it is evaluated as indefinite
   integral)
* updated formconv to 0.8.8 - the cube root is drawn also for negative
   argument 
 
15.7.
* integral - added option to simplify numerator and denominator afre
  multiplying fraction, this allows to integrate functions like
  1/(sqrt(x)+sqrt(x+1))

13.7.
* Fixed english translation (domains of functions)

9.6.
* ODE: y'=exp(2*x-2*y) is solved as separable (maxima reports this
    equation as exact)
* Autonomous systems: support for passing stationary points computed
    by Maxima for further evaluation

27.5.
* ODE: if the ODE is not in the form y'=f(x,y), user can isolate y'
  first and then load into the corresponding form

5.5.
* double integral, 
* 1-st order homogeneous ODE equation, 
* more general right hand side for undetermined coefficients for second 
  order linear ODE

25.4. 
* minima and maxima in two variables: removing "stationary points" if 
  the function takes on complex values, such as log of negative number 
  (thanks to Marie Provaznikova and her students)

22.4. 
* integral: more and better hints, covers e.g. ln^2(x+4)  - substitution
   first and then integration by parts
* fixed bug in partial derivatives - missing ratsimp (thanks to Liiiza)
  and radcan (26.4.)

16.4. 
* function investigation: added freeof test if the equation has been
solved. This removes problem with ((2*(x^2))-log(x)) or (x+1)/atan(x)
* ODE: an error occurs and is logged if the evaluatin of integral is 
  terminanted. Model for the problem is y'=(2*cos(x)*sin(x-1))/(sin(x)+2)**3

13.4.
* more accurate hints in integral asssitant
* only the functions which modify the funciton are listed in integral
  assistant

11.4.
* function investiagtion: warning if arc-trig functions are used to
  solve the problem and some solutions are los. minor bugfix to filter
  out complex solutions

April 2008
* more hints in integral assistant, 
* new error messages in integral assistant ("can't integrate" and 
  "too long formula")
* links from PDF files with ODE's and definite integral into integral assistant

27.3.
* Better fix of the bug from tomorrow: used errcatch in new function 
  maw_solve, which replaces the original solve in some problems.
* Minor bugfix in matching patterns for substitution.
* Used our own mathtex server instead of slow is.mendelu.cz
* integral assistant accepts constants a and b

26.3.
* New version of formconv, some previous changes which are no more necessary
  with this new version (concerning acot function)
* More matching patterns for integral.
* Function investigation - fixed problem with error when solving solve(f,x)=0, 
  for example  if f(x)=acot(x).
  
25.3. 
* hints for substitution in indefinite integral, covers selected basic
  types

24.3.
* many changes in indefinite integral (hints for formulas and
  integration by parts and much more)

20.3.-22.3
* sqrt(x) function does not return value for negative x in calculator 
  for function investigation. This prevents to draw graph of a functions like
  sqrt(x+1)/sqrt(x) for x<-1. The solution is to replace sqrt by the function 
  mysqrt(x) = (x>=0)?sqrt(x):0/0, as suggested by Michael Hofmann.
* Support for volume of revolution. Improved routine which checks that the 
  problem to find area between two curves if well posed.
* Indefinite integral: automatical hints that intergration by parts or 
  expansion into partial fraction is a convenient tool. Improved
  integration by partial fraction, there are still problems with 
  expansion of 1/(x^3+2) into partial fractions - we get either no
  expansion or expansion with complex numbers :(

19.3.
* Regular expressions catch inequalitites which not sharp or writen badly 
  (like x,y>0 or 2x+y>9) and give a hint for few common problems 
  (x,y>0 => x>0 and y>0; 2x+y>9 => 2*x+y>9). 

18.3.
* Fixed bug in particular solution of second order LDE via undetermined 
  coefficients.
* Fixed missing parenthesis in integration by parts in integral
  assistant. Thanks to Mirek Machala.

15.3.-17.3
* graphs of elementary functions: fixed acot function (is continuous at 0), 
  accepts also other than natural logs
* PDF output for inequalities in one and two variables.

12.3.
* started to write logs in english
* derivative is able to handle functions like sin(a(2*x)*x^2)
* fixed few security problems
* fixed many things, hope nothing has been broken, only allowed funcitons 
  or parameters are a and b
* registering project on sourceforge

11.3.
* chybova hlaska pokud se nepodari vyresit nerovnici nebo soustavu
  (tj. pokud soustava nema reseni).
* oprava ztracene mezery v souboru ode.pl (reseni rovnice 
  y'=-cos(x)/sin(x)*y+x/sin(x) davalo chybu)
* oprava parametru pouzitych pro rozparsrovani funkce kvuli derivacim v 
  souborech derivace2.mac a derivace2y.mac (aa->aa[1] - thanks to 
  Harald Geyer)

10.3. 
* novy design stranek (prehlednejsi rozdeleni do tematickych skupin) 
* soustava linearnich nerovnic - zatim jenom v html

7.3. 
* Zobrazuji se jednotliva dilci reseni u definicniho oboru funkce dvou 
  promennych
* Definicni obor funkce jedne promenne 

6.3. 
* U definicniho oboru funkce dvou promennych se zobrazuji i podminky,
  ktere je nutno splnit.
* U hledani stac. bodu funkce dvou promennych je umoznem i vypocet v
  pripade, ze funkce obsahuje parametr (a,b, ...) - pridani promennych
  [x,y] do parametru prikazu solve.

5.3.
* derivace krok po kroku
* u urciteho integralu v geometrii, prubehu funkce a mozna jeste nekde 
  jinde se kontroluje, ze zadana funkce je funkci jedne promenne
* uprava zobrazovani definicniho oboru funkce dvou promennych, vysledek
  se zobrazuje v html strance, ne jako samostatny png soubor.
* negsumdispflag:false u neurciteho integralu

3.3.
* Urcity integral: funkce se kresli ne na intervalu (a,b), ale na
  (a-0.0000001,b+0.0000001), aby byla mensi pravdepodobnost ze vyjde
  log(-1) a aby se tim padem pekne nakreslil graf funkce x*(log(x))^2
* integral: konverze hranatych zavorek na kulate (hranate maji v maxime
   jiny  vyznam)

29.2.
* Integral: zpetna substituce, integral souctu
* Urcity integral: zahazuji se komplexni cisla, tohle resi 
  problem pri kresleni funkci jako arccos(x) nebo sqrt(1-x^2),
  odchytavaji se numericke chyby jako deleni nulou a logaritmus nuly,
  aby nevadily prikresleni grafu

26.2.
* Integral: u substituce se kontroluje, jestli se nepouziva uz jednou
  pouzite pismenko, anglicka verze

23.2.2008 
* Rada vylepseni do kalkulacky s neurcitym integralem a nahled
  zadani v prubehu funkce 
  
21.2.2008
* pridan "pruvodce neurcitym integralem", zatim jenom v cestine, stejne
  jako posunute grafy funkci.

20.2.2008
* pridan prikaz errcatch do filtru, ktery filtruje koreny funkce a
  jejich derivaci u prubehu. Po uprave filtru totiz daval prubeh funkce
  y=tan(x) chybu.

18.2.2008
* Grafy zakladnich elementarnich funkci v posunutem a natazenem tvaru
* Vylepsena detekce komplexnich korenu u prubehu, napriklad 
  x^4-10*x^2-1 hlasilo 4 koreny, ale jsou jenom dva. Pokud je koren moc
  slozity (TeXovsky zapis vic jak 200 znaku) netiskne se.

13.2.2008
* Nova verze programu formconv (resi napriklad problem s (x*log(x))^2) a
  zobrazuje se nahled vzorce v nekterych pripadech, kdy vstupni filtr
  zachyti problem v zapisu matematickeho vzorce (chybi zavorka za
  jemenem funkce a podobne)

9.2.2008
* Prubeh: opraveno derivovani funkci jako 1/2*(x+1/x), pri derivovani se 
  vytyka konstanta v citateli, pokud to jde. Drobne upravy chybovych
  hlasek. Pridano logexpand:false, aby se nasel i zaporny koren funce
  ln(x^2).
* Novy kalkulator: Lagrageuv interpolacni polynom 
* Opraveno zahazovani nerealnych korenu u ODR a u prubehu (zadny koren 
  rovnice x^4+1=0 se od ted uz netvari jako realny)
* MNC: kontrola zapomenutych nebo prebytecnych souradnic a prebytecnych 
  nebo chybejicich carek nebo stredniku
* Lepsi zobrazovani Taylorova polynomu (pridano pfeformat:true)
* prubeh a taylor: uprava, aby se nepouzival formconv (problemy s
  (x*ln(x))^2)
* prubeh: trigsimp se pouzije jenom, kdyz je v zadani trigonometricka
  nebo k ni inverzni funkce. To osetri nezadouci prevod log(x^2) na 
  2*log(x) treba pri derivovani funkce x*log(x^2).
* uprava vstupniho filtru: podrobnejsi chybove hlasky a zakazana
  desetinna cisla (program je nekdy prevadi na zlomky, coz muze vest ke 
  zmateni ctenare), osetreni zpetnych lomitek
* funkce dvou promennych: umi kreslit definicni obor

31.1.2008
* ODE: automaticky se zahazuji komplexni vysledky pri hledani
  konstatnich reseni separovatelne DR a byly opraveny drobne chybky.

30.1.2008 
* Vstupni filtr odchyti pokus pouzit jako oddelovac desetinnych
  mist carku misto tecky a vyvola srozumitelne chybove hlaseni.
* prubeh: Hezci kresleni asymptot (plna modra cara)
* prubeh: Opravena chyba zpusobena koncem radku pri detekci, zda je funkce
  polynom. Opravena kontrola, zda se da kratit: v nekterych pripadech
  davala falesnou chybovou hlasku.

27.1.2008
* pokud je tecka pritomna v jinem kontextu, nez jako oddelovac
  desetinnych mist, vyvola vstupni filtr odpovidajici chybove hlaseni
* prubeh: pokud je zadana racionalni lomena funkce, kde se da kratit,
  program odmitne vypocet a pozaduje zadani ve zkracene forme (citatel
  a jmenovatel nemaji stejne koreny). Zkraceny tvar zlomku je soucasti
  chybove hlasky.

26.1.2008
* prubeh: detekce, jestli zadana funkce je polynom nebo podil dvou
  polynomu a pokud ano, tak se provede detailnejsi analyza (definicni
  obor, body nespojitosti, asymptoty v nekonecnech a bodech
  nespojitosti, postup pri uprave derivace pokud jmenovatel ma vsechny 
  koreny stejne nasobnosti)

24.1.2008
* prubeh: oprava volani programu formconv - pridan parametr -r pri
  vykreslovani grafu (thanks to Zoltan Kovacs). Absence toho parametru
  zpusobovala, ze zlomky typu 1/2 byly pri kresleni grafu programem
  GNUplot povazovane za celociselne deleni a vysledkem byla nula

20.1.2008
* oprava mensi chyby, ktera zpusobovala chybu pri pouziti konstanty %pi
  ve vypoctech (omylem smazana mezera)
* u geometricke aplikace kontrola na spojitost funkci v krajnich bodech
* oprava filtru matematickych vyrazu, vyraz typu 4e^x nespusti
  vypocet, ale zobrazi varovani (zapomenute znamenko pro nasobeni)

19.1.2008
* metoda odhadu partikularniho reseni pro LDR druheho radu, kdy na prave 
  strane je polynom, nebo polynom v soucinu s exponencialni funkci

15.1.2008
* dve jazykove mutace
* uprava vetsiny kalkulatoru

10.1.2008
* bod kolem nehoz se dela Tayloruv polynom muze byt i %pi nebo %e a
  podobne
* nastavena restriktivni pravidla, co je a co neni mozno zapisovat do 
  formularu (pismena s diakritikou, recka pismena jina nez %pi, 
  hyperbolicke funkce a podobne)

9.1.2008
* filtr pi->%pi a osetreni absolutni hodnoty zapsane pomoci svislych car

7.1.2008
* css styly a jednotny vizualni styl html a PDF souboru
* uprava reseni ODE (nejdriv jako linearni, potom pripadne separace)

6.1.2008 
* lepsi separace promennych u ODE prvniho radu a chybova hlaska
  pokud Maxima rovnici nevyresi
* nova verze konverzniho programu formconv, osetruje problem ze obcas
  byly ve TeXovskem vystupu vynechane zavorky
* kodovani cestiny zmeneno na UTF-8
* kontrola parovosti zavorek a prazdnych retezcu
* logovani nekterych matematicky nekorektnich vyrazu do souboru

5.1.2008 
* Taylor: pridana kontrola, jestli je funkce v zadanem bode spojita,
  pokud ne, vypise se varovani. Oprava mensich chyb v TeXovskem ovladaci.

* MNC: Pridan filtr pro vyvolani chyby v pripade, kdy jsou na vstupu
  i jine znaky nez cisla a oddelovace

* Podorobnejsi chybove hlasky v pripade nekorektnich nebo nepovolenych
  dat na vstupu. 

4.1.2008
* NOVA APLIKACE: linearni diferencialni rovnice druheho radu
* Kalkulacka na prubeh funkce se snazi zobrazit i nulove body funkce
* Vstupni formulare byly upraveny aby varovaly uzivatele, pokud
  nenapise explicitne nasobeni a pokud nevyznaci kulatou zavorkou
  rozsah pusobnosti funkci jako sin, cos a podobne

3.1.2008
* Uprava souboru taylor.pl, aby nezjednodusoval zadanou funkci