uClibc now has a math library. muahahahaha!

 -Erik

1 files changed, 115 insertions, 0 deletions

diff --git a/libm/float/ellief.c b/libm/float/ellief.c
new file mode 100644
index 000000000..5c3f822df
--- /dev/null
+++ b/libm/float/ellief.c
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+/*							ellief.c
+ *
+ *	Incomplete elliptic integral of the second kind
+ *
+ *
+ *
+ * SYNOPSIS:
+ *
+ * float phi, m, y, ellief();
+ *
+ * y = ellief( phi, m );
+ *
+ *
+ *
+ * DESCRIPTION:
+ *
+ * Approximates the integral
+ *
+ *
+ *                phi
+ *                 -
+ *                | |
+ *                |                   2
+ * E(phi\m)  =    |    sqrt( 1 - m sin t ) dt
+ *                |
+ *              | |    
+ *               -
+ *                0
+ *
+ * of amplitude phi and modulus m, using the arithmetic -
+ * geometric mean algorithm.
+ *
+ *
+ *
+ * ACCURACY:
+ *
+ * Tested at random arguments with phi in [0, 2] and m in
+ * [0, 1].
+ *                      Relative error:
+ * arithmetic   domain     # trials      peak         rms
+ *    IEEE       0,2        10000       4.5e-7      7.4e-8
+ *
+ *
+ */
+
+
+/*
+Cephes Math Library Release 2.2:  July, 1992
+Copyright 1984, 1987, 1992 by Stephen L. Moshier
+Direct inquiries to 30 Frost Street, Cambridge, MA 02140
+*/
+
+/*	Incomplete elliptic integral of second kind	*/
+
+#include <math.h>
+
+extern float PIF, PIO2F, MACHEPF;
+
+#define fabsf(x) ( (x) < 0 ? -(x) : (x) )
+
+#ifdef ANSIC
+float sqrtf(float), logf(float), sinf(float), tanf(float), atanf(float);
+float ellpef(float), ellpkf(float);
+#else
+float sqrtf(), logf(), sinf(), tanf(), atanf();
+float ellpef(), ellpkf();
+#endif
+
+
+float ellief( float phia, float ma )
+{
+float phi, m, a, b, c, e, temp;
+float lphi, t;
+int d, mod;
+
+phi = phia;
+m = ma;
+if( m == 0.0 )
+	return( phi );
+if( m == 1.0 )
+	return( sinf(phi) );
+lphi = phi;
+if( lphi < 0.0 )
+	lphi = -lphi;
+a = 1.0;
+b = 1.0 - m;
+b = sqrtf(b);
+c = sqrtf(m);
+d = 1;
+e = 0.0;
+t = tanf( lphi );
+mod = (lphi + PIO2F)/PIF;
+
+while( fabsf(c/a) > MACHEPF )
+	{
+	temp = b/a;
+	lphi = lphi + atanf(t*temp) + mod * PIF;
+	mod = (lphi + PIO2F)/PIF;
+	t = t * ( 1.0 + temp )/( 1.0 - temp * t * t );
+	c = 0.5 * ( a - b );
+	temp = sqrtf( a * b );
+	a = 0.5 * ( a + b );
+	b = temp;
+	d += d;
+	e += c * sinf(lphi);
+	}
+
+b = 1.0 - m;
+temp = ellpef(b)/ellpkf(b);
+temp *= (atanf(t) + mod * PIF)/(d * a);
+temp += e;
+if( phi < 0.0 )
+	temp = -temp;
+return( temp );
+}