Log Message:
-----------
Derivatives of absolute values were leaving out the chain rule when
written as |...| (but not as abs(...)). The chain rule is built into
the derivatives of function objects automatically, but not of lists,
which is how |...| is implemented (a special form of parentheses), and
so I missed it when adding the derivative in this form. Argh!
Modified Files:
--------------
pg/lib/Parser:
Differentiation.pm
Revision Data
-------------
Index: Differentiation.pm
===================================================================
RCS file: /webwork/cvs/system/pg/lib/Parser/Differentiation.pm,v
retrieving revision 1.12
retrieving revision 1.13
diff -Llib/Parser/Differentiation.pm -Llib/Parser/Differentiation.pm -u -r1.12 -r1.13
--- lib/Parser/Differentiation.pm
+++ lib/Parser/Differentiation.pm
@@ -602,7 +602,12 @@
sub Parser::List::AbsoluteValue::D {
my $self = shift; my $x = $self->{coords}[0]->copy;
my $equation = $self->{equation};
- return $self->Item("BOP")->new($equation,'/', $x, $self->copy);
+ my $BOP = $self->Item("BOP");
+ return
+ $BOP->new($equation,"*",
+ $BOP->new($equation,'/', $x, $self->copy),
+ $x->D(shift),
+ );
}
|
