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26 lines
454 B
C
26 lines
454 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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z_sqrt (doublecomplex * r, doublecomplex * z)
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{
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double mag, 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 = sqrt (0.5 * (mag + zr));
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r->i = zi / r->r / 2;
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}
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else
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{
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r->i = sqrt (0.5 * (mag - zr));
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if (zi < 0)
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r->i = -r->i;
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r->r = zi / r->i / 2;
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}
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}
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