struct xpr
cxarg (struct cxpr z)
{
int rs, is;
rs = xsgn (&z.re);
is = xsgn (&z.im);
if (rs > 0)
return xatan (xdiv (z.im, z.re));
else if (rs < 0)
{
z.re.nmm[0] ^= xM_sgn;
z.im.nmm[0] ^= xM_sgn;
if (is >= 0)
return xadd (xPi, xatan (xdiv (z.im, z.re)), 0);
else
return xadd (xatan (xdiv (z.im, z.re)), xPi, 1);
}
else /* z.re is zero ! */
{
if (!xsigerr (is == 0, XEDOM, "cxarg()"))
return (is > 0 ? xPi2 : xneg (xPi2));
else
return xneg (xPi2); /* Dummy value :) */
}
}
static
double
satan(double arg)
{
if(arg < sq2m1)
return xatan(arg);
if(arg > sq2p1)
return PIO2 - xatan(1/arg);
return PIO2/2 + xatan((arg-1)/(arg+1));
}
void test_trig()
{
double x;
double y;
RPN::Context cxt;
cxt.insert("x", new RPN::VariableNode(&x));
cxt.insert("y", new RPN::VariableNode(&y));
RPN::Expression xsin("sin x", cxt);
RPN::Expression xcos("cos x", cxt);
RPN::Expression xtan("tan x", cxt);
RPN::Expression xsec("sec x", cxt);
RPN::Expression xcsc("csc x", cxt);
RPN::Expression xcot("cot x", cxt);
RPN::Expression xasin("asin x", cxt);
RPN::Expression xacos("acos x", cxt);
RPN::Expression xatan("atan x", cxt);
RPN::Expression xasec("asec x", cxt);
RPN::Expression xacsc("acsc x", cxt);
RPN::Expression xacot("acot x", cxt);
RPN::Expression xatan2("atan2(x, y)", cxt);
RPN::Expression xacot2("acot2(x, y)", cxt);
for(x = -RPN::Constants::PI; x < RPN::Constants::PI; x += 0.097)
{
insist_equal(xsin.evaluate(), sin(x));
insist_equal(xcos.evaluate(), cos(x));
insist_equal(xtan.evaluate(), tan(x));
insist_equal(xsec.evaluate(), 1.0/cos(x));
insist_equal(xcsc.evaluate(), 1.0/sin(x));
insist_equal(xcot.evaluate(), 1.0/tan(x));
}
for(x = -1; x < 1; x += 0.043)
{
insist_equal(xasin.evaluate(), asin(x));
insist_equal(xacos.evaluate(), acos(x));
insist_equal(xatan.evaluate(), atan(x));
insist_equal(xasec.evaluate(), acos(1.0/x));
insist_equal(xacsc.evaluate(), asin(1.0/x));
insist_equal(xacot.evaluate(), atan(1.0/x));
}
for(x = -1; x < 1; x+= 0.069)
{
for(y = -1; y < 1; y += 0.73)
{
insist_equal(xatan2.evaluate(), atan2(x, y));
insist_equal(xacot2.evaluate(), atan2(y, x));
}
}
}
int
main (void)
{
struct xpr z, f, c;
int k;
printf (" Test of Inverse Trig Functions\n");
printf ("\n Atan:\n");
for (k = 0; k < 3; ++k)
{
switch (k)
{
case 0:
z = dbltox (.5);
break;
case 1:
z = dbltox (1.);
break;
case 2:
z = dbltox (-2.);
break;
}
/* compute extended precision arctangent and tangent */
f = xatan (z);
c = xtan (f);
printf (" %8.4f ", xtodbl (z));
xprxpr (f, decd);
printf ("\n check tan= ");
xprxpr (c, decd);
putchar ('\n');
}
printf ("\n Asin:\n");
for (k = 0; k < 3; ++k)
{
switch (k)
{
case 0:
z = dbltox (.5);
break;
case 1:
z = dbltox (.75);
break;
case 2:
z = dbltox (.25);
break;
}
/* compute extended precision arcsin and sine */
f = xasin (z);
c = xsin (f);
printf (" %8.4f ", xtodbl (z));
xprxpr (f, decd);
printf ("\n check sin= ");
xprxpr (c, decd);
putchar ('\n');
}
printf ("\n Acos:\n");
for (k = 0; k < 3; ++k)
{
switch (k)
{
case 0:
z = dbltox (.5);
break;
case 1:
z = dbltox (.75);
break;
case 2:
z = dbltox (.25);
break;
}
/* compute extended precision arccos and cosine */
f = xacos (z);
c = xcos (f);
printf (" %8.4f ", xtodbl (z));
xprxpr (f, decd);
printf ("\n check cos= ");
xprxpr (c, decd);
putchar ('\n');
}
return 0;
}