## Miscellaneous

### Re: Crash due to 'while loop' and "show me another"?

by Stacey Rodman -
Number of replies: 0

Full code:

DOCUMENT();
"PGstandard.pl",
"PGchoicemacros.pl",
"PGcourse.pl",
"MathObjects.pl",
);

Context('Vector');

$a = random(-5,5,1);$b = random(-5,5,1);
while ($a ==$b) { $b = random(-5,5,1); } # make sure curl is not = 0$c = random(-5,5,1);
$d = random(-5,5,1);$e = random(-5,5,1);
$f = random(-5,5,1);$f1 = nicestring([$a,$d],[ 'y', 'z']);
$f2 = nicestring([$b,  $e],[ 'x', 'z']);$f3 = nicestring([$c,$f],[ 'x', 'y']);

$curl = Vector($f-$e,$d-$c,$b-$a );$p1 = non_zero_random(-5,5,1);
$p2 = random(-5,5,1);$p3 = random(-5,5,1);

$v1 = random(-5,5,1);$v2 = random(-5,5,1);
$v3 = non_zero_random(-5,5,1);$vector = Vector($v1,$v2, $v3);$rotation = $curl.$vector/norm($vector); Context('Numeric'); ## TEXT(beginproblem()); BEGIN_TEXT Consider the vector field $$\vec{F}(x,y,z) = \langle f1, f2, f3 \rangle$$.$BR
Find the divergence and curl of $$\vec{F}$$.  Use <  >  for vectors.
$BR$BR
$$\textrm{div}(\vec{F}) =$$ \{ans_rule(20)\}.
$BR $$\textrm{curl}(\vec{F}) =$$ \{ans_rule(20)\}.$BR
$BR What is the "right-hand" rotation of $$\vec{F}$$ at the point $$(p1,p2,p3 )$$ around the vector $$\langle v1, v2, v3 \rangle$$$BR
$BR $$\textrm{rotation} =$$ \{ans_rule(20)\}. END_TEXT ANS(num_cmp(0)); ANS($curl->cmp());
ANS(\$rotation->cmp());

ENDDOCUMENT();