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Annotation of 42BSD/usr.lib/libF77/z_sqrt.c, revision 1.1

1.1     ! root        1: /*
        !             2:  *     "@(#)z_sqrt.c   1.1"
        !             3:  */
        !             4: 
        !             5: #include "complex"
        !             6: 
        !             7: z_sqrt(r, z)
        !             8: dcomplex *r, *z;
        !             9: {
        !            10: double mag, sqrt(), cabs();
        !            11: 
        !            12: if( (mag = cabs(z->dreal, z->dimag)) == 0.)
        !            13:        r->dreal = r->dimag = 0.;
        !            14: else if(z->dreal > 0)
        !            15:        {
        !            16:        r->dreal = sqrt(0.5 * (mag + z->dreal) );
        !            17:        r->dimag = z->dimag / r->dreal / 2;
        !            18:        }
        !            19: else
        !            20:        {
        !            21:        r->dimag = sqrt(0.5 * (mag - z->dreal) );
        !            22:        if(z->dimag < 0)
        !            23:                r->dimag = - r->dimag;
        !            24:        r->dreal = z->dimag / r->dimag / 2;
        !            25:        }
        !            26: }

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