diff --git a/stim/grids/grid.h b/stim/grids/grid.h
index 8b29714..f8d6f2c 100644
--- a/stim/grids/grid.h
+++ b/stim/grids/grid.h
@@ -5,18 +5,16 @@
 #include <string>
 #include <sstream>
 #include <fstream>
+#include <cstdarg>
 
-#include "../cuda/threads.h"
-#include "../cuda/error.h"
-#include "../cuda/devices.h"
 #include "../math/vector.h"
 
-
 namespace stim{
 
-//This object describes a generic D-dimensional grid containing data of type T
-	// data can be loaded in the form of images
-	// data can be saved in the form of binary files
+/**This object describes a generic D-dimensional grid containing data of type T.
+	Functions are provided for saving and loading binary data.
+
+**/
 template<typename T, unsigned int D = 1>
 class grid{
 
@@ -25,7 +23,7 @@ protected:
 	stim::vec<unsigned long, D> R;		//elements in each dimension
 	T* ptr;									//pointer to the data (on the GPU or CPU)
 
-	//return the total number of values in the binary file
+	///Return the total number of values in the binary file
 	unsigned long samples(){
 
 		unsigned long s = 1;
@@ -33,12 +31,55 @@ protected:
 			s *= R[d];
 
 		return s;
+	}
+
+	///Initializes a grid by allocating the necessary memory and setting all values to zero
+	void init(){
+
+		//calculate the total number of values
+		unsigned long S = samples();
+
+		//allocate memory to store the grid
+		ptr = (T*)malloc(sizeof(T) * S);
+
+		//initialize the memory to zero
+		memset(ptr, 0, sizeof(T) * S);
 
 	}
 
 public:
 
-	//write data to disk
+	///Constructor used to specify the grid size as a vector
+
+	/// @param _R is a vector describing the grid resolution
+	grid( stim::vec<unsigned long, D> _R){
+		
+		//set the grid resolution
+		R = _R;
+
+		init();		
+	}
+
+	///Constructor used to specify the grid size as a set of parameters
+
+	/// @param X0... is a list of values describing the grid size along each dimension
+	grid( unsigned long X0, ...){
+
+		R[0] = X0;
+
+		va_list ap;
+		va_start(ap, X0);
+		for(unsigned int d = 1; d<D; d++)
+			R[d] = va_arg(ap, unsigned long);
+		va_end(ap);
+
+		init();
+
+	}
+
+	///Writes the binary data to disk
+
+	/// @param filename is the name of the binary file to be written
 	void write(std::string filename){
 
 		std::fstream file;
@@ -50,8 +91,11 @@ public:
 		file.write((char *)ptr, samples() * sizeof(T));
 	}
 
-	//load a binary file from disk
-	//		header size is in bytes
+	///Loads a binary file from disk
+
+	/// @param filename is the name of the file containing the binary data
+	/// @param S is the size of the binary file along each dimension
+	/// @param header is the size of the header in bytes
 	void read(std::string filename, stim::vec<unsigned long, D> S, unsigned long header = 0){
 
 		R = S;	//set the sample resolution
@@ -68,8 +112,69 @@ public:
 		file.read((char *)ptr, samples() * sizeof(T));
 	}
 
+	///Gets a single value from the grid given a set of coordinates
+
+	/// @param x0... is a list of coordinates specifying the desired value
+	T get(unsigned long x0, ...){
+
+		va_list ap;
+		
+		unsigned long F = 1;
+		unsigned long p = x0;
+
+		va_start(ap, x0);
+		for(unsigned int d = 1; d<D; d++){
+			F *= R[d-1];
+			p += va_arg(ap, unsigned int) * F;
+		}
+		va_end(ap);
+
+		return ptr[p];
+	}
+
+	///Sets a value in the grid
+
+	/// @param value is the grid point value
+	/// @x0... is the coordinate of the value to be set
+	void set(T value, unsigned long x0, ...){
+
+		va_list ap;
+		
+		unsigned long F = 1;
+		unsigned long p = x0;
+
+		va_start(ap, x0);
+		for(unsigned int d = 1; d<D; d++){
+			F *= R[d-1];
+			p += va_arg(ap, unsigned int) * F;
+		}
+		va_end(ap);
+
+		ptr[p] = value;
+	}
+
+	///Outputs grid data as a string
+	std::string str(){
 
+		std::stringstream result;
 
+		result<<"stim::grid structure of size [";
+		for(unsigned int d = 0; d<D; d++){
+			if(d!=0) result<<", ";
+			result<<R[d];
+		}
+		result<<"]"<<std::endl;
+
+		//calculate the number of values to output
+		unsigned long nV = min(R[0], (unsigned long)10);
+
+		for(unsigned long v = 0; v<nV; v++){
+			result<<ptr[v];
+			if(v != nV-1) result<<", ";
+		}
+
+		return result.str();
+	}
 };
 
 }
diff --git a/stim/grids/image_stack.h b/stim/grids/image_stack.h
index c49bd82..3de2a67 100644
--- a/stim/grids/image_stack.h
+++ b/stim/grids/image_stack.h
@@ -8,8 +8,9 @@
 
 namespace stim{
 
-//this creates a class that can be used to load 3D grid data from stacks of images
-//	The class uses a 4D grid object, where the first dimension is color
+/**This class is used to load 3D grid data from stacks of images
+	The class uses a 4D grid object, where the first dimension is a color value.
+**/
 template<typename T>
 class image_stack : public virtual stim::grid<T, 4>{
 
@@ -22,6 +23,9 @@ protected:
 
 public:
 
+	///Load an image stack based on a file mask. Images are loaded in alphanumeric order.
+
+	/// @param file_mask is the mask describing images to be loaded
 	void load_images(std::string file_mask){
 
 		stim::filename file_path(file_mask);
@@ -65,6 +69,10 @@ public:
 		}
 	}
 
+	///Saves a single page to an image file
+
+	/// @param file_name is the name of the image file to be created
+	/// @param i is the page to be saved
 	void save_image(std::string file_name, unsigned int i){
 
 		//create an image
@@ -76,6 +84,9 @@ public:
 		I.save(file_name);
 	}
 
+	///Saves the entire stack to a set of images
+
+	/// @param file_mask is the mask describing how the file names will be saved (ex. image????.bmp)
 	void save_images(std::string file_mask){
 
 		stim::filename file_path(file_mask);
@@ -93,10 +104,6 @@ public:
 			save_image(file_list[i], i);
 	}
 
-
-
-	
-
 };
 
 
--
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