Log of /trunk/pg/lib/Value/Union.pm
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Revision
3497 -
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Modified
Sat Aug 13 00:25:27 2005 UTC (7 years, 9 months ago) by
dpvc
File length: 8531 byte(s)
Diff to
previous 3477
Added ability for Unions and Sets to simplify themselves
(automatically or on demand), and added flags to the Context and
answer checkers to control these features. The new Context flags
are
reduceUnions tells whether unions are automatically
reduced when they are created.
reduceUnionsForComparison tells whether unions are reduced
before comparing them for equality
or inequality (etc) if they aren't
reduced already.
reduceSets tells whether redundent elements are
removed from sets as they are created.
reduceSetsForComparison tells whether sets are reduced before
comparing them.
All of these default to true.
The Interval, Set, Union, and List answer checkers not have two new
flags for controlling these values:
studentsMustReduceUnions tells whether unions and sets will be
counted as incorrect when they are not
reduced to non-overlapping intervals
and at most one set with no repeated
entries.
showUnionReduceWarnings tells whether an error message will
be produced for non-reduced unions and
sets, or if they will be marked wrong
silently. (Not available in Lists.)
Both of these are true by default, since most professors probably want
their students to write intervals in reduced form. (Is this true?)
This corresponds the the current behavior of the interval checkers,
which require the student's answer to be the same set of intervals as
in the professor's, but with the addition of an error message when the
student answer is not reduced.
Revision
3477 -
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Modified
Thu Aug 11 20:57:18 2005 UTC (7 years, 9 months ago) by
dpvc
File length: 6799 byte(s)
Diff to
previous 3472
Added ability to subtract intervals, sets and unions. Adjusted the
precedence of the union 'U' to be above _ and + so that things like
(1,5) U (7,10) - {8} U (2,3) will do ((1,5) U (7,10)) - ({8} U (2,3))
rather than the previous (1,5) U ((7,10) - {8}) U (2,3). Finally,
added a constant 'R' to the Interval context that is equivalent to
(-inf,inf), so you can do things like R-{0} now.
Still need to work out reducing unions so that things like (1,3)U(2,4)
can become (1,4).
Revision
3472 -
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Modified
Thu Aug 11 14:33:09 2005 UTC (7 years, 9 months ago) by
dpvc
File length: 5502 byte(s)
Diff to
previous 3369
Changes needed to Set object. Also, use Parser to handle unions
defined as strings rather than doing it by hand (that's the whole
point, isn't it?). Added object promotion from lower-precedence
classes (for better error messages), and fixed up the comparison
routine.
Revision
3192 -
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Modified
Wed Mar 16 13:30:28 2005 UTC (8 years, 2 months ago) by
dpvc
File length: 4590 byte(s)
Diff to
previous 2800
Update the overloaded operators so that they can be overridden by
subclasses of the predefined object classes. This involves calling
the objects method rather than using a hard reference to the routine
in the parent class.
Also, change the name of the string comparison routine to
compare_string to avoid conflicts with cmp that is used to produce the
answer checker for the class.
Finally, in Value.pm, promotePrecedence no longer has to do fancy
footwork to get "special" precedence to work (this was a hack to get
around the misfeature of the overloaded operators -- now that that is
being handled correctly, there is no need for it).
Revision
2800 -
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Modified
Sun Sep 19 14:27:39 2004 UTC (8 years, 7 months ago) by
dpvc
File length: 4517 byte(s)
Diff to
previous 2678
Added isZero and isOne checks for Parser::Value objects (i.e., for
constants within formulas). These now correctly handle vector and
matrices, in particular. The isOne and isZero checks are used in the
reduce() method to simplify formulas.
Revision
2678 -
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Modified
Mon Aug 23 23:55:37 2004 UTC (8 years, 8 months ago) by
dpvc
File length: 4555 byte(s)
Diff to
previous 2625
Modified the parser so that the classes for the various object
constructors are stored in the context table rather than hard-coded
into the parser. That way, you can override the default classes with
your own. This gives you even more complete control to modify the
parser. (You had been able to replace the definitions of operators,
functions and list-like objects, but could not override the behaviour
of numbers, strings, variables, and so on. Now you can.)
This effects most of the files, but only by changing the name of the
calls that create the various objects.
There are also a couple of other minor fixes.
Revision
2625 -
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Modified
Mon Aug 16 18:35:12 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4529 byte(s)
Diff to
previous 2612
Added string comparison to all Value object classes (to compare the
string value of an object to another string).
Overloaded perl '.' operator to do dot product when the operands are
formulas returning vectors. (Part of the auto-generation of
formulas).
A few improvements to real and complex class output results.
Made Union class slightly more robust and removed need for makeUnion
method other than in the Union itself.
Revision
2606 -
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Modified
Sat Aug 14 11:25:47 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4550 byte(s)
Diff to
previous 2601
Can now specify that the objects stringify themselfs in their TeX
forms rather than their answer-string forms. This makes it easier to
use the objects in the text of a problem (without having to call ->TeX
explicitly each reference).
Use
Context()->texStrings
to start outputting TeX strings, and
Context()->normalStrings
to switch back.
Revision
2601 -
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Modified
Fri Aug 13 19:06:09 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4567 byte(s)
Diff to
previous 2594
Added ability to report incorrect coordinates in point and vector
answers, and incorrect endpoints and endpoint types in intervals.
Separated these kinds of checks from the typeMatch check, where they
didn't really belong.
Added ability to specify intervals and unions as strings in Interval()
and Union(), which makes it easier to make constants of these types.
There are still problems comparing intervals that contain infinities;
I really need to make the infinity object to solve this, so have put
off trying to fix that for now.
Revision
2594 -
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Modified
Thu Aug 12 20:17:18 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4447 byte(s)
Diff to
previous 2592
Fixes for handling intervals better. In particular, deal better with
ambiguous situations, like (1,2) that could be a point.
You can use [a,a] to specify the single point a. I'd like to make {a}
represent this (and maybe even {a,b,c} to form finite sets), but this
would interfere with the use of { and } as alternative parentheses.
(Does anyone really use these?)
Do we need a cross product for intervals (and sets) as a means of
representing regions in R^2 (or higher)?
Revision
2592 -
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Modified
Thu Aug 12 16:40:47 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4397 byte(s)
Diff to
previous 2579
A number of small fixes. Most were to fix minor bugs in string and
TeX output, particulary for the various list-based objects (like
vectors, intervals, etc.). There were also some bug fixes in the
comparison routines. Some additional checks were added for valid
intervals when the coordinates are formulas.
Revision
2579 -
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Modified
Mon Aug 9 21:38:01 2004 UTC (8 years, 9 months ago) by
dpvc
File length: 4293 byte(s)
Diff to
previous 2558
Significant update to new parser.
New features include:
Better control over format of vector output (you can now
specify ijk-format rather than <...> format)
"Fuzzy" reals, where the relations like == return true when the
two values are "close enough". (This is controlable using
parameters similar to those used in NUM_CMP).
The fuzzy reals are now used in vectors/points/matrices/complexes/intervals
and so on so that their relations will also be fuzzy. E.g.,
(1E-13,2) == (0,3) will be true, and norm(Vector(0,1E-13)) will
equal 0.
The two main portions of the parser (the Parser and Value packages)
now share a common context object for configuration purposes.
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