49 lines
904 B
C
49 lines
904 B
C
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/*
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casinf.c
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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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/* casin (Z ) = -I * clog(I * Z + csqrt (1.0 - Z * Z))) */
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float complex casinf (float complex Z)
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{
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float complex Res;
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float x, y;
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x = __real__ Z;
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y = __imag__ Z;
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if (y == 0.0f)
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{
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__real__ Res = asinf (x);
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__imag__ Res = 0.0f;
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}
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else /* -I * clog(I * Z + csqrt(1.0 - Z * Z))) */
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{
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float complex ZZ;
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/* Z * Z = ((x - y) * (x + y)) + (2.0 * x * y) * I */
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/* calculate 1 - Z * Z */
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__real__ ZZ = 1.0f - (x - y) * (x + y);
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__imag__ ZZ = -2.0f * x * y;
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ZZ = csqrtf (ZZ);
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/* add I * Z to ZZ */
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__real__ ZZ -= y;
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__imag__ ZZ += x;
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ZZ = clogf (ZZ);
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/* mult by -I */
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__real__ Res = __imag__ ZZ;
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__imag__ Res = - __real__ ZZ;
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}
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return (Res);
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}
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