42 lines
815 B
C
42 lines
815 B
C
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/* ctanl.c */
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/*
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Contributed by Danny Smith
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2005-01-04
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*/
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#include <math.h>
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#include <complex.h>
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#include <errno.h>
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/* ctan (x + I * y) = (sin (2 * x) + I * sinh(2 * y))
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/ (cos (2 * x) + cosh (2 * y)) */
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long double complex ctanl (long double complex Z)
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{
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long double complex Res;
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long double two_I = 2.0L * __imag__ Z;
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long double two_R = 2.0L * __real__ Z;
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long double denom = cosl (two_R) + coshl (two_I);
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if (denom == 0.0L)
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{
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errno = ERANGE;
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__real__ Res = HUGE_VALL;
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__imag__ Res = HUGE_VALL;
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}
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else if (isinf (denom))
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{
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errno = ERANGE;
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__real__ Res = 0.0;
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__imag__ Res = two_I > 0 ? 1.0L : -1.0L;
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}
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else
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{
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__real__ Res = sinl (two_R) / denom;
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__imag__ Res = sinhl (two_I) / denom;
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}
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return Res;
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}
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