45 lines
787 B
C
45 lines
787 B
C
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/* ctanhf.c */
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/*
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Contributed by Danny Smith
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2004-12-24
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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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/*
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ctanh (x + I * y) = (sinh (2 * x) + sin (2 * y) * I )
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/ (cosh (2 * x) + cos (2 * y)) .
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*/
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float complex
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ctanhf (float complex Z)
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{
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float complex Res;
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float two_R = 2.0f * __real__ Z;
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float two_I = 2.0f * __imag__ Z;
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float denom = coshf (two_R) + cosf (two_I);
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if (denom == 0.0f)
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{
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errno = ERANGE;
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__real__ Res = HUGE_VALF;
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__imag__ Res = HUGE_VALF;
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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 = two_R > 0 ? 1.0f : -1.0f;
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__imag__ Res = 0.0f;
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}
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else
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{
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__real__ Res = sinhf (two_R) / denom;
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__imag__ Res = sinf (two_I) / denom;
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}
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return Res;
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}
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