Log Message:
-----------
Make adaptive parameters try again if they fail to be found the first
time (Gavin has found cases where the random points cause the
coefficient matrix to be singular, so a second try should resolve the
problem).
Modified Files:
--------------
pg/lib/Value:
Formula.pm
Revision Data
-------------
Index: Formula.pm
===================================================================
RCS file: /webwork/cvs/system/pg/lib/Value/Formula.pm,v
retrieving revision 1.59
retrieving revision 1.60
diff -Llib/Value/Formula.pm -Llib/Value/Formula.pm -u -r1.59 -r1.60
--- lib/Value/Formula.pm
+++ lib/Value/Formula.pm
@@ -182,6 +182,11 @@
# to the ORIGINAL correct answer. (This will have to be
# fixed if we ever do adaptive parameters for non-real formulas)
#
+ # FIXME: it doesn't make sense to apply the ORIGINAL value's
+ # tolerance, and causes problems when the values
+ # differ in magnitude by much. Gavin has found several
+ # situations where this is a problem.
+ #
if ($l->AdaptParameters($r,$self->{context}->variables->parameters)) {
my $avalues = $l->{test_adapt};
my $tolerance = $self->getFlag('tolerance',1E-4);
@@ -412,53 +417,59 @@
#
sub AdaptParameters {
my $l = shift; my $r = shift;
- my @params = @_; my $d = scalar(@params);
+ my @params = @_; my $d = scalar(@params); my $D;
return 0 if $d == 0; return 0 unless $l->usesOneOf(@params);
$l->Error("Adaptive parameters can only be used for real-valued formulas")
unless $l->{tree}->isRealNumber;
+
#
- # Get coefficient matrix of adaptive parameters
- # and value vector for linear system
+ # Try up to three times (the random points might not work the first time)
#
- my ($p,$v) = $l->createRandomPoints($d);
- my @P = (0) x $d; my ($f,$F) = ($l->{f},$r->{f});
- my @A = (); my @b = ();
- foreach my $i (0..$d-1) {
- my @a = (); my @p = @{$p->[$i]};
- foreach my $j (0..$d-1) {
- $P[$j] = 1; push(@a,(&$f(@p,@P)-$v->[$i])->value);
- $P[$j] = 0;
+ foreach my $attempt (1..3) {
+ #
+ # Get coefficient matrix of adaptive parameters
+ # and value vector for linear system
+ #
+ my ($p,$v) = $l->createRandomPoints($d);
+ my @P = (0) x $d; my ($f,$F) = ($l->{f},$r->{f});
+ my @A = (); my @b = ();
+ foreach my $i (0..$d-1) {
+ my @a = (); my @p = @{$p->[$i]};
+ foreach my $j (0..$d-1) {
+ $P[$j] = 1; push(@a,(&$f(@p,@P)-$v->[$i])->value);
+ $P[$j] = 0;
+ }
+ push @A, [@a]; push @b, [(&$F(@p,@P)-$v->[$i])->value];
}
- push @A, [@a]; push @b, [(&$F(@p,@P)-$v->[$i])->value];
- }
- #
- # Use MatrixReal1.pm to solve system of linear equations
- #
- my $M = MatrixReal1->new($d,$d); $M->[0] = \@A;
- my $B = MatrixReal1->new($d,1); $B->[0] = \@b;
- ($M,$B) = $M->normalize($B);
- $M = $M->decompose_LR;
- if (($d,$B,$M) = $M->solve_LR($B)) {
- if ($d == 0) {
- #
- # Get parameter values and recompute the points using them
- #
- my @a; my $i = 0; my $max = $l->getFlag('max_adapt',1E8);
- foreach my $row (@{$B->[0]}) {
- if (abs($row->[0]) > $max) {
- $max = Value::makeValue($max); $row->[0] = Value::makeValue($row->[0]);
- $l->Error(["Constant of integration is too large: %s\n(maximum allowed is %s)",
- $row->[0]->string,$max->string]) if $params[$i] eq 'C0';
- $l->Error(["Adaptive constant is too large: %s = %s\n(maximum allowed is %s)",
- $params[$i],$row->[0]->string,$max->string]);
- }
- push @a, $row->[0]; $i++;
+ #
+ # Use MatrixReal1.pm to solve system of linear equations
+ #
+ my $M = MatrixReal1->new($d,$d); $M->[0] = \@A;
+ my $B = MatrixReal1->new($d,1); $B->[0] = \@b;
+ ($M,$B) = $M->normalize($B);
+ $M = $M->decompose_LR;
+ if (($D,$B,$M) = $M->solve_LR($B)) {
+ if ($D == 0) {
+ #
+ # Get parameter values and recompute the points using them
+ #
+ my @a; my $i = 0; my $max = $l->getFlag('max_adapt',1E8);
+ foreach my $row (@{$B->[0]}) {
+ if (abs($row->[0]) > $max) {
+ $max = Value::makeValue($max); $row->[0] = Value::makeValue($row->[0]);
+ $l->Error(["Constant of integration is too large: %s\n(maximum allowed is %s)",
+ $row->[0]->string,$max->string]) if $params[$i] eq 'C0' or $params[$i] eq 'n00';
+ $l->Error(["Adaptive constant is too large: %s = %s\n(maximum allowed is %s)",
+ $params[$i],$row->[0]->string,$max->string]);
+ }
+ push @a, $row->[0]; $i++;
+ }
+ my $context = $l->context;
+ foreach my $i (0..$#a) {$context->{variables}{$params[$i]}{value} = $a[$i]}
+ $l->{parameters} = [@a];
+ $l->createAdaptedValues;
+ return 1;
}
- my $context = $l->context;
- foreach my $i (0..$#a) {$context->{variables}{$params[$i]}{value} = $a[$i]}
- $l->{parameters} = [@a];
- $l->createAdaptedValues;
- return 1;
}
}
$l->Error("Can't solve for adaptive parameters");
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