Updated logistic regression example

Signed-off-by: Fabian Sauter <sauter.fabian@mailbox.org>

examples/logistic_regression/shader/CMakeLists.txt

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.15)
+
+# To add more shaders simply copy the vulkan_compile_shader command and replace it with your new shader
+vulkan_compile_shader(INFILE my_shader.comp
+                      OUTFILE my_shader.hpp
+                      NAMESPACE "shader"
+                      RELATIVE_PATH "${kompute_SOURCE_DIR}/cmake")
+
+# vulkan_compile_shader(INFILE my_shader2.comp
+#                       OUTFILE my_shader2.hpp
+#                       NAMESPACE "shader"
+#                       RELATIVE_PATH "${kompute_SOURCE_DIR}/cmake")
+
+# Then add it to the library, so you can access it later in your code
+add_library(shader "${CMAKE_CURRENT_BINARY_DIR}/my_shader.hpp"
+#                  "${CMAKE_CURRENT_BINARY_DIR}/my_shader2.hpp"
+)
+
+set_target_properties(shader PROPERTIES LINKER_LANGUAGE CXX)
+target_include_directories(shader PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>)

examples/logistic_regression/shader/my_shader.comp

@@ -0,0 +1,54 @@
+#version 450
+
+layout (constant_id = 0) const uint M = 0;
+
+layout (local_size_x = 1) in;
+
+layout(set = 0, binding = 0) buffer bxi { float xi[]; };
+layout(set = 0, binding = 1) buffer bxj { float xj[]; };
+layout(set = 0, binding = 2) buffer by { float y[]; };
+layout(set = 0, binding = 3) buffer bwin { float win[]; };
+layout(set = 0, binding = 4) buffer bwouti { float wouti[]; };
+layout(set = 0, binding = 5) buffer bwoutj { float woutj[]; };
+layout(set = 0, binding = 6) buffer bbin { float bin[]; };
+layout(set = 0, binding = 7) buffer bbout { float bout[]; };
+layout(set = 0, binding = 8) buffer blout { float lout[]; };
+
+float m = float(M);
+
+float sigmoid(float z) {
+    return 1.0 / (1.0 + exp(-z));
+}
+
+float inference(vec2 x, vec2 w, float b) {
+    // Compute the linear mapping function
+    float z = dot(w, x) + b;
+    // Calculate the y-hat with sigmoid 
+    float yHat = sigmoid(z);
+    return yHat;
+}
+
+float calculateLoss(float yHat, float y) {
+    return -(y * log(yHat)  +  (1.0 - y) * log(1.0 - yHat));
+}
+
+void main() {
+    uint idx = gl_GlobalInvocationID.x;
+
+    vec2 wCurr = vec2(win[0], win[1]);
+    float bCurr = bin[0];
+
+    vec2 xCurr = vec2(xi[idx], xj[idx]);
+    float yCurr = y[idx];
+
+    float yHat = inference(xCurr, wCurr, bCurr);
+
+    float dZ = yHat - yCurr;
+    vec2 dW = (1. / m) * xCurr * dZ;
+    float dB = (1. / m) * dZ;
+    wouti[idx] = dW.x;
+    woutj[idx] = dW.y;
+    bout[idx] = dB;
+
+    lout[idx] = calculateLoss(yHat, yCurr);
+}