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diff --git a/nuttx/libc/math/lib_erff.c b/nuttx/libc/math/lib_erff.c
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+++ b/nuttx/libc/math/lib_erff.c
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+/************************************************************************
+ * libc/math/lib_erff.c
+ *
+ *   Copyright (C) 2015 Brennan Ashton. All rights reserved.
+ *   Author: Brennan Ashton <bashton@brennanashton.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <math.h>
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+float erff(float x)
+{
+  /* This implementation comes from the Handbook of Mathmatical Functions
+   * The implementations in this book are not protected by copyright.
+   * erf comes from formula 7.1.26
+   */
+
+  char sign;
+  float t;
+  float a1, a2, a3, a4, a5, p;
+
+  a1 =  0.254829592;
+  a2 = -0.284496736;
+  a3 =  1.421413741;
+  a4 = -1.453152027;
+  a5 =  1.061405429;
+  p  =  0.3275911;
+ 
+  sign = (x >= 0 ? 1 : -1);
+  t = 1.0/(1.0 + p*x);
+  return sign * (1.0 - (((((a5 * t + a4) * t) + a3) * t + a2) * t + a1) * t * expf(-x * x));
+}