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author | ljo <ljo@FreeBSD.org> | 1994-10-26 18:17:41 +0000 |
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committer | ljo <ljo@FreeBSD.org> | 1994-10-26 18:17:41 +0000 |
commit | 2195d627fb793fec6c00bdddf1c4d46982b9f27f (patch) | |
tree | c2961f38c1507b80baefaca1d568747c113f28c0 /lib/libF77/c_sqrt.c | |
parent | 80b2e1963004e4ae0173b4f9bc965518ba81d3b0 (diff) | |
download | FreeBSD-src-2195d627fb793fec6c00bdddf1c4d46982b9f27f.zip FreeBSD-src-2195d627fb793fec6c00bdddf1c4d46982b9f27f.tar.gz |
Library for f2c (part 2 of 2)
Obtained from: netlib.att.com
Diffstat (limited to 'lib/libF77/c_sqrt.c')
-rw-r--r-- | lib/libF77/c_sqrt.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/libF77/c_sqrt.c b/lib/libF77/c_sqrt.c new file mode 100644 index 0000000..3b7342f --- /dev/null +++ b/lib/libF77/c_sqrt.c @@ -0,0 +1,34 @@ +#include "f2c.h" + +#ifdef KR_headers +extern double sqrt(), f__cabs(); + +VOID c_sqrt(r, z) complex *r, *z; +#else +#undef abs +#include "math.h" +extern double f__cabs(double, double); + +void c_sqrt(complex *r, complex *z) +#endif +{ +double mag, t; + +if( (mag = f__cabs(z->r, z->i)) == 0.) + r->r = r->i = 0.; +else if(z->r > 0) + { + r->r = t = sqrt(0.5 * (mag + z->r) ); + t = z->i / t; + r->i = 0.5 * t; + } +else + { + t = sqrt(0.5 * (mag - z->r) ); + if(z->i < 0) + t = -t; + r->i = t; + t = z->i / t; + r->r = 0.5 * t; + } +} |