/*
* arcsinh(x) == log [ x + sqrt(x^2 + 1) ]
*
* also, use arcsinh(-x) == -arcsinh(x)
*/
void m_apm_arcsinh(M_APM rr, int places, M_APM aa)
{
M_APM tmp0, tmp1, tmp2;
/* result is 0 if input is 0 */
if (aa->m_apm_sign == 0)
{
M_set_to_zero(rr);
return;
}
tmp0 = M_get_stack_var();
tmp1 = M_get_stack_var();
tmp2 = M_get_stack_var();
m_apm_absolute_value(tmp0, aa);
m_apm_multiply(tmp1, tmp0, tmp0);
m_apm_add(tmp2, tmp1, MM_One);
m_apm_sqrt(tmp1, (places + 6), tmp2);
m_apm_add(tmp2, tmp0, tmp1);
m_apm_log(rr, places, tmp2);
rr->m_apm_sign = aa->m_apm_sign; /* fix final sign */
M_restore_stack(3);
}
/*
* arccosh(x) == log [ x + sqrt(x^2 - 1) ]
*
* x >= 1.0
*/
void m_apm_arccosh(M_APM rr, int places, M_APM aa)
{
M_APM tmp1, tmp2;
int ii;
ii = m_apm_compare(aa, MM_One);
if (ii == -1) /* x < 1 */
{
M_apm_log_error_msg(M_APM_RETURN, "\'m_apm_arccosh\', Argument < 1");
M_set_to_zero(rr);
return;
}
tmp1 = M_get_stack_var();
tmp2 = M_get_stack_var();
m_apm_multiply(tmp1, aa, aa);
m_apm_subtract(tmp2, tmp1, MM_One);
m_apm_sqrt(tmp1, (places + 6), tmp2);
m_apm_add(tmp2, aa, tmp1);
m_apm_log(rr, places, tmp2);
M_restore_stack(2);
}
/*
Calculate arctan using the identity :
x
arctan (x) == arcsin [ --------------- ]
sqrt(1 + x^2)
*/
void m_apm_arctan(M_APM rr, int places, M_APM xx)
{
M_APM tmp8, tmp9;
if (xx->m_apm_sign == 0) /* input == 0 ?? */
{
M_set_to_zero(rr);
return;
}
if (xx->m_apm_exponent <= -4) /* input close to 0 ?? */
{
M_arctan_near_0(rr, places, xx);
return;
}
if (xx->m_apm_exponent >= 4) /* large input */
{
M_arctan_large_input(rr, places, xx);
return;
}
tmp8 = M_get_stack_var();
tmp9 = M_get_stack_var();
m_apm_multiply(tmp9, xx, xx);
m_apm_add(tmp8, tmp9, MM_One);
m_apm_sqrt(tmp9, (places + 6), tmp8);
m_apm_divide(tmp8, (places + 6), xx, tmp9);
m_apm_arcsin(rr, places, tmp8);
M_restore_stack(2);
}
/*
* compute r = sqrt(1 - a ^ 2).
*/
void M_cos_to_sin(M_APM r, int places, M_APM a)
{
M_APM tmp1, tmp2;
tmp1 = M_get_stack_var();
tmp2 = M_get_stack_var();
m_apm_multiply(tmp1, a, a);
m_apm_subtract(tmp2, MM_One, tmp1);
m_apm_sqrt(r, places, tmp2);
M_restore_stack(2);
}
/*
* functions returns TRUE if the M_APM input number is prime
* FALSE if it is not
*/
int is_number_prime(M_APM input)
{
int ii, ret, index;
char sbuf[32];
/*
* for reference:
*
* table size of 2 to filter multiples of 2 and 3
* table size of 8 to filter multiples of 2, 3 and 5
* table size of 480 to filter multiples of 2,3,5,7, and 11
*
* this increment table will filter out all numbers
* that are multiples of 2,3,5 and 7.
*/
static char incr_table[48] = {
2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6, 2, 6, 4, 2,
6, 4, 6, 8, 4, 2, 4, 2, 4, 8, 6, 4, 6, 2, 4, 6,
2, 6, 6, 4, 2, 4, 6, 2, 6, 4, 2, 4, 2, 10, 2, 10 };
/*
* since the real algorithm starts at 11 (to syncronize
* with the increment table), we will cheat for numbers < 10.
*/
if (m_apm_compare(input, MM_Ten) <= 0)
{
m_apm_to_integer_string(sbuf, input);
ii = atoi(sbuf);
if (ii == 2 || ii == 3 || ii == 5 || ii == 7)
return(TRUE);
else
return(FALSE);
}
ret = FALSE;
index = 0;
/*
* see if the input number is a
* multiple of 3, 5, or 7.
*/
m_apm_integer_div_rem(M_quot, M_rem, input, MM_Three);
if (m_apm_sign(M_rem) == 0) /* remainder == 0 */
return(ret);
m_apm_integer_div_rem(M_quot, M_rem, input, MM_Five);
if (m_apm_sign(M_rem) == 0)
return(ret);
m_apm_set_long(M_digit, 7L);
m_apm_integer_div_rem(M_quot, M_rem, input, M_digit);
if (m_apm_sign(M_rem) == 0)
return(ret);
ii = m_apm_exponent(input) + 16;
m_apm_sqrt(M_tmp1, ii, input);
m_apm_add(M_limit, MM_Two, M_tmp1);
m_apm_set_long(M_digit, 11L); /* now start at '11' to check */
while (TRUE)
{
if (m_apm_compare(M_digit, M_limit) >= 0)
{
ret = TRUE;
break;
}
m_apm_integer_div_rem(M_quot, M_rem, input, M_digit);
if (m_apm_sign(M_rem) == 0) /* remainder == 0 */
break;
m_apm_set_long(M_tmp1, (long)incr_table[index]);
m_apm_add(M_tmp0, M_digit, M_tmp1);
m_apm_copy(M_digit, M_tmp0);
if (++index == 48)
index = 0;
}
return(ret);
}
void M_log_AGM_R_func(M_APM rr, int places, M_APM aa, M_APM bb)
{
M_APM tmp1, tmp2, tmp3, tmp4, tmpC2, sum, pow_2, tmpA0, tmpB0;
int tolerance, dplaces;
tmpA0 = M_get_stack_var();
tmpB0 = M_get_stack_var();
tmpC2 = M_get_stack_var();
tmp1 = M_get_stack_var();
tmp2 = M_get_stack_var();
tmp3 = M_get_stack_var();
tmp4 = M_get_stack_var();
sum = M_get_stack_var();
pow_2 = M_get_stack_var();
tolerance = places + 8;
dplaces = places + 16;
m_apm_copy(tmpA0, aa);
m_apm_copy(tmpB0, bb);
m_apm_copy(pow_2, MM_0_5);
m_apm_multiply(tmp1, aa, aa); /* 0.5 * [ a ^ 2 - b ^ 2 ] */
m_apm_multiply(tmp2, bb, bb);
m_apm_subtract(tmp3, tmp1, tmp2);
m_apm_multiply(sum, MM_0_5, tmp3);
while (TRUE)
{
m_apm_subtract(tmp1, tmpA0, tmpB0); /* C n+1 = 0.5 * [ An - Bn ] */
m_apm_multiply(tmp4, MM_0_5, tmp1); /* C n+1 */
m_apm_multiply(tmpC2, tmp4, tmp4); /* C n+1 ^ 2 */
/* do the AGM */
m_apm_add(tmp1, tmpA0, tmpB0);
m_apm_multiply(tmp3, MM_0_5, tmp1);
m_apm_multiply(tmp2, tmpA0, tmpB0);
m_apm_sqrt(tmpB0, dplaces, tmp2);
m_apm_round(tmpA0, dplaces, tmp3);
/* end AGM */
m_apm_multiply(tmp2, MM_Two, pow_2);
m_apm_copy(pow_2, tmp2);
m_apm_multiply(tmp1, tmpC2, pow_2);
m_apm_add(tmp3, sum, tmp1);
if ((tmp1->m_apm_sign == 0) ||
((-2 * tmp1->m_apm_exponent) > tolerance))
break;
m_apm_round(sum, dplaces, tmp3);
}
m_apm_subtract(tmp4, MM_One, tmp3);
m_apm_reciprocal(rr, places, tmp4);
M_restore_stack(9);
}
void m_apm_root4(M_APM x, int dec_places, M_APM y)
{
m_apm_sqrt(x, dec_places, y);
m_apm_copy(y, x);
m_apm_sqrt(x, dec_places, y);
}
void m_apm_sqrt_mt(M_APM rr, int places, M_APM aa)
{
m_apm_enter();
m_apm_sqrt(rr,places,aa);
m_apm_leave();
}
/*
* Calculate PI using the AGM (Arithmetic-Geometric Mean)
*
* Init : A0 = 1
* B0 = 1 / sqrt(2)
* Sum = 1
*
* Iterate: n = 1...
*
*
* A = 0.5 * [ A + B ]
* n n-1 n-1
*
*
* B = sqrt [ A * B ]
* n n-1 n-1
*
*
*
* C = 0.5 * [ A - B ]
* n n-1 n-1
*
*
* 2 n+1
* Sum = Sum - C * 2
* n
*
*
* At the end when C is 'small enough' :
* n
*
* 2
* PI = 4 * A / Sum
* n+1
*
* -OR-
*
* 2
* PI = ( A + B ) / Sum
* n n
*
*/
void M_calculate_PI_AGM(M_APM outv, int places)
{
M_APM tmp1, tmp2, a0, b0, c0, a1, b1, sum, pow_2;
int dplaces, nn;
tmp1 = M_get_stack_var();
tmp2 = M_get_stack_var();
a0 = M_get_stack_var();
b0 = M_get_stack_var();
c0 = M_get_stack_var();
a1 = M_get_stack_var();
b1 = M_get_stack_var();
sum = M_get_stack_var();
pow_2 = M_get_stack_var();
dplaces = places + 16;
m_apm_copy(a0, MM_One);
m_apm_copy(sum, MM_One);
m_apm_copy(pow_2, MM_Four);
m_apm_sqrt(b0, dplaces, MM_0_5); /* sqrt(0.5) */
while (TRUE)
{
m_apm_add(tmp1, a0, b0);
m_apm_multiply(a1, MM_0_5, tmp1);
m_apm_multiply(tmp1, a0, b0);
m_apm_sqrt(b1, dplaces, tmp1);
m_apm_subtract(tmp1, a0, b0);
m_apm_multiply(c0, MM_0_5, tmp1);
/*
* the net 'PI' calculated from this iteration will
* be accurate to ~4 X the value of (c0)'s exponent.
* this was determined experimentally.
*/
nn = -4 * c0->m_apm_exponent;
m_apm_multiply(tmp1, c0, c0);
m_apm_multiply(tmp2, tmp1, pow_2);
m_apm_subtract(tmp1, sum, tmp2);
m_apm_round(sum, dplaces, tmp1);
if (nn >= dplaces)
break;
m_apm_copy(a0, a1);
m_apm_copy(b0, b1);
m_apm_multiply(tmp1, pow_2, MM_Two);
m_apm_copy(pow_2, tmp1);
}
m_apm_add(tmp1, a1, b1);
m_apm_multiply(tmp2, tmp1, tmp1);
m_apm_divide(tmp1, dplaces, tmp2, sum);
m_apm_round(outv, places, tmp1);
M_restore_stack(9);
}
