42 lines
779 B
C
42 lines
779 B
C
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/* ctanf.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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/* 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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float complex ctanf (float complex Z)
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{
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float complex Res;
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float two_I = 2.0f * __imag__ Z;
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float two_R = 2.0f * __real__ Z;
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float denom = cosf (two_R) + coshf (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 = 0.0;
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__imag__ Res = two_I > 0 ? 1.0f : -1.0f;
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}
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else
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{
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__real__ Res = sinf (two_R) / denom;
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__imag__ Res = sinhf (two_I) / denom;
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}
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return Res;
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}
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