eigenmath/denominator.cpp

80 lines
966 B
C++

#include "stdafx.h"
#include "defs.h"
void
eval_denominator(void)
{
push(cadr(p1));
eval();
denominator();
}
void
denominator(void)
{
int h;
save();
p1 = pop();
if (car(p1) == symbol(ADD)) {
push(p1);
rationalize();
p1 = pop();
}
if (car(p1) == symbol(MULTIPLY)) {
h = tos;
p1 = cdr(p1);
while (iscons(p1)) {
push(car(p1));
denominator();
p1 = cdr(p1);
}
multiply_all(tos - h);
} else if (isrational(p1)) {
push(p1);
mp_denominator();
} else if (car(p1) == symbol(POWER) && isnegativeterm(caddr(p1))) {
push(p1);
reciprocate();
} else
push(one);
restore();
}
#if SELFTEST
static char *s[] = {
"denominator(2/3)",
"3",
"denominator(x)",
"1",
"denominator(1/x)",
"x",
"denominator(a+b)",
"1",
"denominator(1/a+1/b)",
"a*b",
// denominator function expands
"denominator(1/(x-1)/(x-2))",
"x^2-3*x+2",
};
void
test_denominator(void)
{
test(__FILE__, s, sizeof s / sizeof (char *));
}
#endif