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Annotation of researchv10no/libF77/c_sqrt.c, revision 1.1.1.1

1.1       root        1: #include "f2c.h"
                      2: 
                      3: #ifdef KR_headers
                      4: extern double sqrt(), f__cabs();
                      5: 
                      6: VOID c_sqrt(r, z) complex *r, *z;
                      7: #else
                      8: #undef abs
                      9: #include "math.h"
                     10: extern double f__cabs(double, double);
                     11: 
                     12: void c_sqrt(complex *r, complex *z)
                     13: #endif
                     14: {
                     15: double mag, t;
                     16: 
                     17: if( (mag = f__cabs(z->r, z->i)) == 0.)
                     18:        r->r = r->i = 0.;
                     19: else if(z->r > 0)
                     20:        {
                     21:        r->r = t = sqrt(0.5 * (mag + z->r) );
                     22:        t = z->i / t;
                     23:        r->i = 0.5 * t;
                     24:        }
                     25: else
                     26:        {
                     27:        t = sqrt(0.5 * (mag - z->r) );
                     28:        if(z->i < 0)
                     29:                t = -t;
                     30:        r->i = t;
                     31:        t = z->i / t;
                     32:        r->r = 0.5 * t;
                     33:        }
                     34: }

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