C++11

#include "cl.hpp" // OpenCL, here cl_float4 is defined
typedef std::array<cl_float4, 4> mat4;

// Diagonal matrix
mat4 diag(float xs, float ys, float zs, float ws) {
	return mat4 {{
		{xs,   0,  0,  0},
		{0,   ys,  0,  0},
		{0,   0,  zs,  0},
		{0,   0,  0,   ws}
	}};
}

// Unit matrix
mat4 eye() {
	return diag(1, 1, 1, 1);
}


// Isotropic scaling
mat4 scale(float s) {
	return diag(s, s, s, 1);
}


// Euler rotation matrices
mat4 eulerz(float alpha) {
	float c = cos(alpha);
	float s = sin(alpha);
	return mat4 {{
		{ c,  s,  0, 0},
		{-s,  c,  0, 0},
		{ 0,  0,  1, 0},
		{ 0,  0,  0, 1}
	}};
}