56 lines
867 B
C
56 lines
867 B
C
/*
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csqrt.c
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Contributed by Danny Smith
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2003-10-20
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*/
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#include <math.h>
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#include <complex.h>
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double complex csqrt (double complex Z)
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{
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double complex Res;
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double t;
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double x = __real__ Z;
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double y = __imag__ Z;
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if (y == 0.0)
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{
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if (x < 0.0)
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{
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__real__ Res = 0.0;
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__imag__ Res = sqrt (-x);
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}
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else
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{
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__real__ Res = sqrt (x);
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__imag__ Res = 0.0;
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}
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}
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else if (x == 0.0)
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{
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t = sqrt(0.5 * fabs (y));
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__real__ Res = y > 0 ? t : -t;
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__imag__ Res = t;
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}
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else
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{
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t = sqrt (2.0 * (_hypot (x, y) + fabs (x)));
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if ( x > 0.0)
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{
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__real__ Res = 0.5 * t;
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__imag__ Res = y / t;
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}
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else
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{
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__real__ Res = fabs ( y / t);
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__imag__ Res = (y < 0.0 ? -0.5 : 0.5) * t;
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}
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}
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return Res;
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}
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