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31 lines
490 B
C
31 lines
490 B
C
#include "f2c.h"
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#undef abs
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#include "math.h"
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extern double f__cabs (double, double);
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void
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c_sqrt (complex * r, complex * z)
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{
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double mag, t;
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double zi = z->i, zr = z->r;
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if ((mag = f__cabs (zr, zi)) == 0.)
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r->r = r->i = 0.;
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else if (zr > 0)
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{
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r->r = t = sqrt (0.5 * (mag + zr));
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t = zi / t;
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r->i = 0.5 * t;
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}
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else
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{
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t = sqrt (0.5 * (mag - zr));
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if (zi < 0)
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t = -t;
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r->i = t;
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t = zi / t;
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r->r = 0.5 * t;
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}
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}
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