diff --git a/Cargo.toml b/Cargo.toml
index 27f53bdf..a8ecfdf4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -37,7 +37,7 @@ flate2 = { version = "1.0", features = ["cloudflare_zlib"], default-features = f
 shellwords = "1.1.0"
 blas = "0.22"
 intel-mkl-src = {version= "0.7.0", default-features = false, features=["download", "mkl-static-lp64-seq"]}
-
+libm = "0.2.6"
 [build-dependencies]
 cbindgen = "0.23.0"
 
diff --git a/src/block_sigmoid.rs b/src/block_sigmoid.rs
index 0f91492e..d3beb683 100644
--- a/src/block_sigmoid.rs
+++ b/src/block_sigmoid.rs
@@ -82,15 +82,15 @@ impl BlockTrait for BlockSigmoid
 
                 // for now doing the actual slow sigmoid computation. once we establish a baseline,
                 // we can replace with a fast approximation or a lookup table
-                if x  < 0 {
-                    let epx = f32::pow(e, x);
-                    let s = epx / (1 + epx);
+                if x  < 0. {
+                    let epx = f32::powf(e, x);
+                    let s = epx / (1.0 + epx);
                     *pb.tape.get_unchecked_mut(self.output_offset + i) = s;
-                    *pb.tape.get_unchecked_mut(self.input_offset + i) = s * (1 - s);
+                    *pb.tape.get_unchecked_mut(self.input_offset + i) = s * (1.0 - s);
                 } else {
-                    let s = 1 / (1 + f32::pow(e, -x));
+                    let s = 1.0 / (1.0 + f32::powf(e, -x));
                     *pb.tape.get_unchecked_mut(self.output_offset + i) = s;
-                    *pb.tape.get_unchecked_mut(self.input_offset + i) = s * (1 - s);
+                    *pb.tape.get_unchecked_mut(self.input_offset + i) = s * (1.0 - s);
                 }
             }
 
@@ -116,7 +116,7 @@ impl BlockTrait for BlockSigmoid
         unsafe {
             for i in 0..self.num_inputs as usize {
                 let x = *pb.tape.get_unchecked_mut(self.input_offset + i);
-                *pb.tape.get_unchecked_mut(self.output_offset + i) = 1 / (1 + f32::pow(e, -x));
+                *pb.tape.get_unchecked_mut(self.output_offset + i) = 1.0 / (1.0 + f32::powf(e, -x));
             }
             block_helpers::forward(further_blocks, fb, pb);
         } // unsafe end
diff --git a/src/block_tanh.rs b/src/block_tanh.rs
index 5efb4f3a..798a408c 100644
--- a/src/block_tanh.rs
+++ b/src/block_tanh.rs
@@ -90,7 +90,7 @@ impl BlockTrait for BlockTanh
                 // we can try to replace with a lookup table
                 let t = tanhf(x);
                 *pb.tape.get_unchecked_mut(self.output_offset + i) = t;
-                *pb.tape.get_unchecked_mut(self.input_offset + i) = 1 - t*t; // derivative
+                *pb.tape.get_unchecked_mut(self.input_offset + i) = 1. - t*t; // derivative
             }
 
             block_helpers::forward_backward(further_blocks, fb, pb, update);
diff --git a/src/lib.rs b/src/lib.rs
index d69bf3f0..ec878cf0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,6 +22,9 @@ mod port_buffer;
 mod block_neural;
 mod block_misc;
 mod block_relu;
+mod block_leaky_relu;
+mod block_tanh;
+mod block_sigmoid;
 mod block_normalize;
 mod graph;
 
diff --git a/src/regressor.rs b/src/regressor.rs
index 0c995807..45b66405 100644
--- a/src/regressor.rs
+++ b/src/regressor.rs
@@ -223,7 +223,7 @@ impl Regressor  {
                         println!("Tanh layer");
                     },
                     NNActivation::Sigmoid => {
-                        output = block_tanh::new_sigmoid_block(&mut bg, &mi, output).unwrap();
+                        output = block_sigmoid::new_sigmoid_block(&mut bg, &mi, output).unwrap();
                         println!("Sigmoid layer");
                     }
                 }