Myshrimp

CMakeLists.txt

@@ -77,6 +77,7 @@ option(NCNN_PYTHON "build python api" OFF)
 option(NCNN_INT8 "int8 inference" ON)
 option(NCNN_BF16 "bf16 inference" ON)
 option(NCNN_FORCE_INLINE "force inline some function" ON)
+option(NCNN_SIMPLEMATH "minimal math library emulation" OFF)
 
 if(ANDROID OR IOS OR NCNN_SIMPLESTL OR CMAKE_CROSSCOMPILING)
     option(NCNN_DISABLE_RTTI "disable rtti" ON)

src/CMakeLists.txt

@@ -39,6 +39,7 @@ set(ncnn_SRCS
     simpleocv.cpp
     simpleomp.cpp
     simplestl.cpp
+    simplemath.cpp
 )
 
 if(ANDROID)
@@ -576,6 +577,7 @@ if(NCNN_INSTALL_SDK)
         simpleocv.h
         simpleomp.h
         simplestl.h
+        simplemath.h
         vulkan_header_fix.h
         ${CMAKE_CURRENT_BINARY_DIR}/ncnn_export.h
         ${CMAKE_CURRENT_BINARY_DIR}/layer_shader_type_enum.h

src/platform.h.in

@@ -60,6 +60,7 @@
 #cmakedefine01 NCNN_INT8
 #cmakedefine01 NCNN_BF16
 #cmakedefine01 NCNN_FORCE_INLINE
+#cmakedefine01 NCNN_SIMPLEMATH
 
 #cmakedefine NCNN_VERSION_STRING "@NCNN_VERSION_STRING@"
 

src/simplemath.cpp

@@ -0,0 +1,78 @@
+#include "platform.h"
+#ifdef NCNN_SIMPLEMATH
+#include"simplemath.h"
+#include <stdlib.h>
+#include<stdio.h>
+float absolute(float x)//returns the absolute value of a number
+{
+	if (x < 0)x = -x;
+	return x;
+}
+
+float Factorial(int x)//returns the factorial of a number
+{
+	if (x == 1 || x == 0)return 1;
+	else
+		return 1.0 * x * Factorial(x - 1);
+}
+
+
+float nth(float x, int n)//returns the value of a number(x) to the power of n
+{
+	if (n > 0)
+	{
+		return x * nth(x, n - 1);
+	}
+	if (n == 0)
+	{
+		return 1;
+	}
+	if (n < 0)
+	{
+		return (1 / x) * nth(x, n + 1);
+	}
+}
+float Bernoulli(int x)//Bernoulli numbers
+{
+	int k = x;
+	float B = 0;
+	if (x == 0)
+		return 1;
+	else
+		if (x > 1 && x % 2 == 1)
+		{
+			return 0;
+		}
+		else
+		{
+			while (k)
+			{
+				k--;
+				B += -1.0 * (Factorial(x) * Bernoulli(k)) / (Factorial(x - k) * Factorial(k) * (x - k + 1));
+			}
+			return B;
+		}
+}
+float tan(float x)//the accuracy remains 0.000001
+{
+	int i = 1;
+	float e = 1, sum = 0;
+	while (x < (PI / 2))x += PI;
+	while (x > (PI / 2))x -= PI;
+	if (x == (PI/ 2))
+	{
+		printf("\tNaN\n");
+		return 0;
+	}
+	while (absolute(e) > accuracy && i <= 24)//adjust Bernoulli in consideration of calculating speed.
+	{
+		e = 1.0 * (nth(-1, i - 1) * nth(2, 2 * i) * (nth(2, 2 * i) - 1.0) * Bernoulli(2 * i) * nth(x, 2 * i - 1)) / (Factorial(2 * i));
+		sum += e;
+		i++;
+	}
+	return sum;
+}
+#endif
+
+
+

src/simplemath.h

@@ -0,0 +1,7 @@
+#ifndef TAN_H
+#define TAN_H
+#include<stdio.h>
+#define PI 3.14159265
+#define accuracy 0.000001
+float tan(float x);
+#endif