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34 lines
565 B
C
34 lines
565 B
C
#include "f2c.h"
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#ifdef KR_headers
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double sqrt(), f__cabs();
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VOID z_sqrt(resx, z) doublecomplex *resx, *z;
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#else
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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 z_sqrt(doublecomplex *resx, doublecomplex *z)
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#endif
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{
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double mag;
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doublecomplex res;
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if( (mag = f__cabs(z->r, z->i)) == 0.)
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res.r = res.i = 0.;
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else if(z->r > 0)
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{
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res.r = sqrt(0.5 * (mag + z->r) );
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res.i = z->i / res.r / 2;
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}
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else
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{
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res.i = sqrt(0.5 * (mag - z->r) );
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if(z->i < 0)
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res.i = - res.i;
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res.r = z->i / res.i / 2;
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}
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resx->r = res.r;
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resx->i = res.i;
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}
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