Removes DenseVector

src/math/mod.rs

@@ -1,3 +1,46 @@
 pub mod distance;
 
-pub static EPSILON:f64 = 2.2204460492503131e-16_f64;
+pub static EPSILON:f64 = 2.2204460492503131e-16_f64;
+
+pub trait NumericExt {
+    fn ln_1pe(&self) -> f64;
+    fn sigmoid(&self) -> f64;
+}
+
+impl NumericExt for f64 {
+
+    fn ln_1pe(&self) -> f64{
+        let y = 0.;
+
+        if *self > 15. {
+            return *self;
+        } else {
+            return self.exp().ln_1p();
+        }
+
+    }
+
+    fn sigmoid(&self) -> f64 {
+        
+        if *self < -40. {
+            return 0.;
+        } else if *self > 40. {
+            return 1.;
+        } else {
+            return 1. / (1. + f64::exp(-self))
+        }
+        
+    }
+}
+
+#[cfg(test)]
+mod tests {    
+    use super::*;     
+
+    #[test]
+    fn sigmoid() { 
+        assert_eq!(1.0.sigmoid(), 0.7310585786300049);
+        assert_eq!(41.0.sigmoid(), 1.);
+        assert_eq!((-41.0).sigmoid(), 0.);
+    }
+}