90 lines
1.1 KiB
C++
90 lines
1.1 KiB
C++
//-----------------------------------------------------------------------------
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//
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// Bessel Y function
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//
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// Input: tos-2 x (can be a symbol or expr)
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//
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// tos-1 n
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//
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// Output: Result on stack
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//
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//-----------------------------------------------------------------------------
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#include "stdafx.h"
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#include "defs.h"
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void
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eval_bessely(void)
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{
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push(cadr(p1));
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eval();
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push(caddr(p1));
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eval();
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bessely();
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}
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void
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bessely(void)
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{
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save();
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yybessely();
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restore();
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}
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#define X p1
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#define N p2
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void
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yybessely(void)
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{
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double d;
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int n;
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N = pop();
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X = pop();
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push(N);
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n = pop_integer();
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if (isdouble(X) && n != (int) 0x80000000) {
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d = yn(n, X->u.d);
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push_double(d);
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return;
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}
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if (isnegativeterm(N)) {
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push_integer(-1);
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push(N);
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power();
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push_symbol(BESSELY);
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push(X);
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push(N);
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negate();
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list(3);
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multiply();
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return;
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}
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push_symbol(BESSELY);
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push(X);
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push(N);
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list(3);
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return;
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}
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#if SELFTEST
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static char *s[] = {
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"bessely(x,n)",
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"bessely(x,n)",
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};
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void
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test_bessely(void)
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{
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test(__FILE__, s, sizeof s / sizeof (char *));
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}
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#endif
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