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30 lines
492 B
C
30 lines
492 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(r, z) doublecomplex *r, *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 *r, doublecomplex *z)
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#endif
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{
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double mag;
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if( (mag = f__cabs(z->r, z->i)) == 0.)
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r->r = r->i = 0.;
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else if(z->r > 0)
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{
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r->r = sqrt(0.5 * (mag + z->r) );
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r->i = z->i / 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 - z->r) );
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if(z->i < 0)
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r->i = - r->i;
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r->r = z->i / r->i / 2;
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}
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}
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