diff --git a/Manual.ipynb b/Manual.ipynb
index 87c2bda..1b171ea 100644
--- a/Manual.ipynb
+++ b/Manual.ipynb
@@ -1,16 +1,5 @@
 {
  "cells": [
-  {
-   "cell_type": "code",
-   "execution_count": 1,
-   "metadata": {
-    "collapsed": true
-   },
-   "outputs": [],
-   "source": [
-    "using Revise\n"
-   ]
-  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -24,24 +13,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "\u001b[1m\u001b[36mINFO: \u001b[39m\u001b[22m\u001b[36mPrecompiling module FProfile.\n",
-      "\u001b[39m"
-     ]
-    },
     {
      "data": {
       "text/plain": [
-       "ProfileData(41 backtraces)"
+       "ProfileData(40 backtraces)"
       ]
      },
-     "execution_count": 2,
+     "execution_count": 1,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -61,16 +42,16 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       "ProfileData(982 backtraces)"
+       "ProfileData(920 backtraces)"
       ]
      },
-     "execution_count": 3,
+     "execution_count": 2,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -83,7 +64,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "`ProfileData` merely wraps the internal data in `Base.Profile`. Do not forget that Julia compiles code the first time a function is run; if you do not want to measure compilation time, execute your code once before profiling."
+    "Do not forget that Julia compiles code the first time a function is run; if you do not want to measure compilation time, execute your code once before profiling."
    ]
   },
   {
@@ -92,28 +73,28 @@
    "source": [
     "# Flat view\n",
     "\n",
-    "FProfile's `flat` report is a [dataframe](http://juliadata.github.io/DataFrames.jl/stable/man/getting_started/#Getting-Started-1), however no particular knowledge of dataframes is necessary. I'll provide a few common operations below."
+    "FProfile's `flat` report is a [dataframe](http://juliadata.github.io/DataFrames.jl/stable/man/getting_started/#Getting-Started-1). No particular knowledge of dataframes is necessary. I'll provide a few common operations below."
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/html": [
-       "<table class=\"data-frame\"><thead><tr><th></th><th>count_percent</th><th>stackframe</th><th>specialization</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>99.9</td><td>execute_request(::ZMQ.Socket, ::IJulia.Msg) at execute_request.jl:154</td><td>MethodInstance for execute_request(::ZMQ.Socket, ::IJulia.Msg)</td><td>execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115</td><td>/Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl</td><td>IJulia.execute_request</td><td>IJulia</td></tr><tr><th>2</th><td>99.9</td><td>anonymous at &lt;missing&gt;:?</td><td>MethodInstance for missing_info()</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>3</th><td>99.9</td><td>macro expansion at FProfile.jl:52 [inlined]</td><td>MethodInstance for missing_info()</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>4</th><td>99.9</td><td>(::IJulia.##14#17)() at task.jl:335</td><td>MethodInstance for (::IJulia.##14#17)()</td><td>(::IJulia.##14#17)() in IJulia at task.jl:335</td><td>task.jl</td><td>IJulia.#14</td><td>IJulia</td></tr><tr><th>5</th><td>99.9</td><td>eventloop(::ZMQ.Socket) at eventloop.jl:8</td><td>MethodInstance for eventloop(::ZMQ.Socket)</td><td>eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2</td><td>/Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl</td><td>IJulia.eventloop</td><td>IJulia</td></tr></tbody></table>"
+       "<table class=\"data-frame\"><thead><tr><th></th><th>count_pct</th><th>stackframe</th><th>specialization</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>99.89</td><td>execute_request(::ZMQ.Socket, ::IJulia.Msg) at execute_request.jl:154</td><td>MethodInstance for execute_request(::ZMQ.Socket, ::IJulia.Msg)</td><td>execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115</td><td>/Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl</td><td>IJulia.execute_request</td><td>IJulia</td></tr><tr><th>2</th><td>99.89</td><td>anonymous at &lt;missing&gt;:?</td><td>MethodInstance for missing_info()</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>3</th><td>99.89</td><td>macro expansion at FProfile.jl:52 [inlined]</td><td>MethodInstance for missing_info()</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>4</th><td>99.89</td><td>(::IJulia.##14#17)() at task.jl:335</td><td>MethodInstance for (::IJulia.##14#17)()</td><td>(::IJulia.##14#17)() in IJulia at task.jl:335</td><td>task.jl</td><td>IJulia.#14</td><td>IJulia</td></tr><tr><th>5</th><td>99.89</td><td>eventloop(::ZMQ.Socket) at eventloop.jl:8</td><td>MethodInstance for eventloop(::ZMQ.Socket)</td><td>eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2</td><td>/Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl</td><td>IJulia.eventloop</td><td>IJulia</td></tr></tbody></table>"
       ],
       "text/plain": [
        "5×7 DataFrames.DataFrame\n",
-       "│ Row │ count_percent │\n",
-       "├─────┼───────────────┤\n",
-       "│ 1   │ 99.9          │\n",
-       "│ 2   │ 99.9          │\n",
-       "│ 3   │ 99.9          │\n",
-       "│ 4   │ 99.9          │\n",
-       "│ 5   │ 99.9          │\n",
+       "│ Row │ count_pct │\n",
+       "├─────┼───────────┤\n",
+       "│ 1   │ 99.89     │\n",
+       "│ 2   │ 99.89     │\n",
+       "│ 3   │ 99.89     │\n",
+       "│ 4   │ 99.89     │\n",
+       "│ 5   │ 99.89     │\n",
        "\n",
        "│ Row │ stackframe                                                            │\n",
        "├─────┼───────────────────────────────────────────────────────────────────────┤\n",
@@ -156,7 +137,7 @@
        "│ 5   │ IJulia.eventloop                  │ IJulia               │"
       ]
      },
-     "execution_count": 4,
+     "execution_count": 3,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -189,20 +170,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 4,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/html": [
-       "<table class=\"data-frame\"><thead><tr><th></th><th>count_percent</th><th>end_count_percent</th><th>stackframe</th><th>specialization</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>100.0</td><td>0.0</td><td>do_computation(::Int64) at In[5]:1</td><td>MethodInstance for do_computation(::Int64)</td><td>do_computation(n) in Main at In[5]:1</td><td>In[5]</td><td>do_computation</td><td>Main</td></tr><tr><th>2</th><td>100.0</td><td>100.0</td><td>sum_of_sin(::Int64) at In[5]:2</td><td>MethodInstance for sum_of_sin(::Int64)</td><td>sum_of_sin(n) in Main at In[5]:2</td><td>In[5]</td><td>sum_of_sin</td><td>Main</td></tr></tbody></table>"
+       "<table class=\"data-frame\"><thead><tr><th></th><th>count_pct</th><th>end_count_pct</th><th>stackframe</th><th>specialization</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>100.0</td><td>0.0</td><td>do_computation(::Int64) at In[4]:1</td><td>MethodInstance for do_computation(::Int64)</td><td>do_computation(n) in Main at In[4]:1</td><td>In[4]</td><td>do_computation</td><td>Main</td></tr><tr><th>2</th><td>100.0</td><td>100.0</td><td>sum_of_sin(::Int64) at In[4]:2</td><td>MethodInstance for sum_of_sin(::Int64)</td><td>sum_of_sin(n) in Main at In[4]:2</td><td>In[4]</td><td>sum_of_sin</td><td>Main</td></tr></tbody></table>"
       ],
       "text/plain": [
        "2×8 DataFrames.DataFrame\n",
-       "│ Row │ count_percent │ end_count_percent │ stackframe                         │\n",
-       "├─────┼───────────────┼───────────────────┼────────────────────────────────────┤\n",
-       "│ 1   │ 100.0         │ 0.0               │ do_computation(::Int64) at In[5]:1 │\n",
-       "│ 2   │ 100.0         │ 100.0             │ sum_of_sin(::Int64) at In[5]:2     │\n",
+       "│ Row │ count_pct │ end_count_pct │ stackframe                         │\n",
+       "├─────┼───────────┼───────────────┼────────────────────────────────────┤\n",
+       "│ 1   │ 100.0     │ 0.0           │ do_computation(::Int64) at In[4]:1 │\n",
+       "│ 2   │ 100.0     │ 100.0         │ sum_of_sin(::Int64) at In[4]:2     │\n",
        "\n",
        "│ Row │ specialization                             │\n",
        "├─────┼────────────────────────────────────────────┤\n",
@@ -211,11 +192,11 @@
        "\n",
        "│ Row │ method                               │ file  │ function       │ module │\n",
        "├─────┼──────────────────────────────────────┼───────┼────────────────┼────────┤\n",
-       "│ 1   │ do_computation(n) in Main at In[5]:1 │ In[5] │ do_computation │ Main   │\n",
-       "│ 2   │ sum_of_sin(n) in Main at In[5]:2     │ In[5] │ sum_of_sin     │ Main   │"
+       "│ 1   │ do_computation(n) in Main at In[4]:1 │ In[4] │ do_computation │ Main   │\n",
+       "│ 2   │ sum_of_sin(n) in Main at In[4]:2     │ In[4] │ sum_of_sin     │ Main   │"
       ]
      },
-     "execution_count": 5,
+     "execution_count": 4,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -238,37 +219,37 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/html": [
-       "<table class=\"data-frame\"><thead><tr><th></th><th>count_percent</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>99.9</td><td>include_string(mod::Module, code::String, fname::String) in Compat at /Users/cedric/.julia/v0.6/Compat/src/Compat.jl:464</td><td>/Users/cedric/.julia/v0.6/Compat/src/Compat.jl</td><td>include_string</td><td>Compat</td></tr><tr><th>2</th><td>99.9</td><td>execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115</td><td>/Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl</td><td>IJulia.execute_request</td><td>IJulia</td></tr><tr><th>3</th><td>99.9</td><td>include_string(txt::String, fname::String) in Base at loading.jl:515</td><td>loading.jl</td><td>include_string</td><td>Base</td></tr><tr><th>4</th><td>99.9</td><td>eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2</td><td>/Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl</td><td>IJulia.eventloop</td><td>IJulia</td></tr><tr><th>5</th><td>99.9</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>6</th><td>99.9</td><td>(::IJulia.##14#17)() in IJulia at task.jl:335</td><td>task.jl</td><td>IJulia.#14</td><td>IJulia</td></tr><tr><th>7</th><td>99.59</td><td>second_derivative(f::Function, x::Number) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:71</td><td>/Users/cedric/.julia/v0.6/Calculus/src/derivative.jl</td><td>Calculus.second_derivative</td><td>Calculus</td></tr><tr><th>8</th><td>48.37</td><td>derivative(f::Function, ftype::Symbol, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:2</td><td>/Users/cedric/.julia/v0.6/Calculus/src/derivative.jl</td><td>Calculus.derivative</td><td>Calculus</td></tr><tr><th>9</th><td>23.32</td><td>finite_difference_hessian(f::Function, g::Function, x::Number, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl:224</td><td>/Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl</td><td>Calculus.finite_difference_hessian</td><td>Calculus</td></tr><tr><th>10</th><td>19.86</td><td>finite_difference(f::Function, x::T, dtype::Symbol) where T&lt;:Number in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl:48</td><td>/Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl</td><td>Calculus.finite_difference</td><td>Calculus</td></tr></tbody></table>"
+       "<table class=\"data-frame\"><thead><tr><th></th><th>count_pct</th><th>method</th><th>file</th><th>function</th><th>module</th></tr></thead><tbody><tr><th>1</th><td>99.89</td><td>missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25</td><td>/Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl</td><td>FProfile.MissingInfo.missing_info</td><td>FProfile.MissingInfo</td></tr><tr><th>2</th><td>99.89</td><td>include_string(txt::String, fname::String) in Base at loading.jl:515</td><td>loading.jl</td><td>include_string</td><td>Base</td></tr><tr><th>3</th><td>99.89</td><td>execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115</td><td>/Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl</td><td>IJulia.execute_request</td><td>IJulia</td></tr><tr><th>4</th><td>99.89</td><td>(::IJulia.##14#17)() in IJulia at task.jl:335</td><td>task.jl</td><td>IJulia.#14</td><td>IJulia</td></tr><tr><th>5</th><td>99.89</td><td>include_string(mod::Module, code::String, fname::String) in Compat at /Users/cedric/.julia/v0.6/Compat/src/Compat.jl:464</td><td>/Users/cedric/.julia/v0.6/Compat/src/Compat.jl</td><td>include_string</td><td>Compat</td></tr><tr><th>6</th><td>99.89</td><td>eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2</td><td>/Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl</td><td>IJulia.eventloop</td><td>IJulia</td></tr><tr><th>7</th><td>99.57</td><td>second_derivative(f::Function, x::Number) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:71</td><td>/Users/cedric/.julia/v0.6/Calculus/src/derivative.jl</td><td>Calculus.second_derivative</td><td>Calculus</td></tr><tr><th>8</th><td>53.91</td><td>derivative(f::Function, ftype::Symbol, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:2</td><td>/Users/cedric/.julia/v0.6/Calculus/src/derivative.jl</td><td>Calculus.derivative</td><td>Calculus</td></tr><tr><th>9</th><td>19.57</td><td>finite_difference_hessian(f::Function, g::Function, x::Number, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl:224</td><td>/Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl</td><td>Calculus.finite_difference_hessian</td><td>Calculus</td></tr><tr><th>10</th><td>14.67</td><td>finite_difference(f::Function, x::T, dtype::Symbol) where T&lt;:Number in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl:48</td><td>/Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl</td><td>Calculus.finite_difference</td><td>Calculus</td></tr></tbody></table>"
       ],
       "text/plain": [
        "10×5 DataFrames.DataFrame\n",
-       "│ Row │ count_percent │\n",
-       "├─────┼───────────────┤\n",
-       "│ 1   │ 99.9          │\n",
-       "│ 2   │ 99.9          │\n",
-       "│ 3   │ 99.9          │\n",
-       "│ 4   │ 99.9          │\n",
-       "│ 5   │ 99.9          │\n",
-       "│ 6   │ 99.9          │\n",
-       "│ 7   │ 99.59         │\n",
-       "│ 8   │ 48.37         │\n",
-       "│ 9   │ 23.32         │\n",
-       "│ 10  │ 19.86         │\n",
+       "│ Row │ count_pct │\n",
+       "├─────┼───────────┤\n",
+       "│ 1   │ 99.89     │\n",
+       "│ 2   │ 99.89     │\n",
+       "│ 3   │ 99.89     │\n",
+       "│ 4   │ 99.89     │\n",
+       "│ 5   │ 99.89     │\n",
+       "│ 6   │ 99.89     │\n",
+       "│ 7   │ 99.57     │\n",
+       "│ 8   │ 53.91     │\n",
+       "│ 9   │ 19.57     │\n",
+       "│ 10  │ 14.67     │\n",
        "\n",
        "│ Row │ method                                                                                                                                                       │\n",
        "├─────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤\n",
-       "│ 1   │ include_string(mod::Module, code::String, fname::String) in Compat at /Users/cedric/.julia/v0.6/Compat/src/Compat.jl:464                                     │\n",
-       "│ 2   │ execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115                                                        │\n",
-       "│ 3   │ include_string(txt::String, fname::String) in Base at loading.jl:515                                                                                         │\n",
-       "│ 4   │ eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2                                                                           │\n",
-       "│ 5   │ missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25                                                              │\n",
-       "│ 6   │ (::IJulia.##14#17)() in IJulia at task.jl:335                                                                                                                │\n",
+       "│ 1   │ missing_info() in FProfile.MissingInfo at /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl:25                                                              │\n",
+       "│ 2   │ include_string(txt::String, fname::String) in Base at loading.jl:515                                                                                         │\n",
+       "│ 3   │ execute_request(socket, msg) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl:115                                                        │\n",
+       "│ 4   │ (::IJulia.##14#17)() in IJulia at task.jl:335                                                                                                                │\n",
+       "│ 5   │ include_string(mod::Module, code::String, fname::String) in Compat at /Users/cedric/.julia/v0.6/Compat/src/Compat.jl:464                                     │\n",
+       "│ 6   │ eventloop(socket) in IJulia at /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl:2                                                                           │\n",
        "│ 7   │ second_derivative(f::Function, x::Number) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:71                                             │\n",
        "│ 8   │ derivative(f::Function, ftype::Symbol, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl:2                                  │\n",
        "│ 9   │ finite_difference_hessian(f::Function, g::Function, x::Number, dtype::Symbol) in Calculus at /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl:224 │\n",
@@ -276,12 +257,12 @@
        "\n",
        "│ Row │ file                                                        │\n",
        "├─────┼─────────────────────────────────────────────────────────────┤\n",
-       "│ 1   │ /Users/cedric/.julia/v0.6/Compat/src/Compat.jl              │\n",
-       "│ 2   │ /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl     │\n",
-       "│ 3   │ loading.jl                                                  │\n",
-       "│ 4   │ /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl           │\n",
-       "│ 5   │ /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl          │\n",
-       "│ 6   │ task.jl                                                     │\n",
+       "│ 1   │ /Users/cedric/.julia/v0.6/FProfile/src/FProfile.jl          │\n",
+       "│ 2   │ loading.jl                                                  │\n",
+       "│ 3   │ /Users/cedric/.julia/v0.6/IJulia/src/execute_request.jl     │\n",
+       "│ 4   │ task.jl                                                     │\n",
+       "│ 5   │ /Users/cedric/.julia/v0.6/Compat/src/Compat.jl              │\n",
+       "│ 6   │ /Users/cedric/.julia/v0.6/IJulia/src/eventloop.jl           │\n",
        "│ 7   │ /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl        │\n",
        "│ 8   │ /Users/cedric/.julia/v0.6/Calculus/src/derivative.jl        │\n",
        "│ 9   │ /Users/cedric/.julia/v0.6/Calculus/src/finite_difference.jl │\n",
@@ -289,19 +270,19 @@
        "\n",
        "│ Row │ function                           │ module               │\n",
        "├─────┼────────────────────────────────────┼──────────────────────┤\n",
-       "│ 1   │ include_string                     │ Compat               │\n",
-       "│ 2   │ IJulia.execute_request             │ IJulia               │\n",
-       "│ 3   │ include_string                     │ Base                 │\n",
-       "│ 4   │ IJulia.eventloop                   │ IJulia               │\n",
-       "│ 5   │ FProfile.MissingInfo.missing_info  │ FProfile.MissingInfo │\n",
-       "│ 6   │ IJulia.#14                         │ IJulia               │\n",
+       "│ 1   │ FProfile.MissingInfo.missing_info  │ FProfile.MissingInfo │\n",
+       "│ 2   │ include_string                     │ Base                 │\n",
+       "│ 3   │ IJulia.execute_request             │ IJulia               │\n",
+       "│ 4   │ IJulia.#14                         │ IJulia               │\n",
+       "│ 5   │ include_string                     │ Compat               │\n",
+       "│ 6   │ IJulia.eventloop                   │ IJulia               │\n",
        "│ 7   │ Calculus.second_derivative         │ Calculus             │\n",
        "│ 8   │ Calculus.derivative                │ Calculus             │\n",
        "│ 9   │ Calculus.finite_difference_hessian │ Calculus             │\n",
        "│ 10  │ Calculus.finite_difference         │ Calculus             │"
       ]
      },
-     "execution_count": 6,
+     "execution_count": 5,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -319,22 +300,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 6,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       " 229 ...ulus/src/derivative.jl:71; second_derivative(::Function, ::F...\n",
-       "  227 .../finite_difference.jl:224; finite_difference_hessian(::Func...\n",
-       "   159 .../finite_difference.jl:55; finite_difference(::Calculus.##1...\n",
-       "   29  .../finite_difference.jl:27; finite_difference(::Calculus.##1...\n",
-       "   3   .../finite_difference.jl:54; finite_difference(::Calculus.##1...\n",
-       "   4   .../finite_difference.jl:0; finite_difference(::Calculus.##1...\n",
-       "  2   .../finite_difference.jl:0; finite_difference_hessian(::Func...\n"
+       " 180 ...ulus/src/derivative.jl:71; second_derivative(::Function, ::F...\n",
+       "  175 .../finite_difference.jl:224; finite_difference_hessian(::Func...\n",
+       "   112 .../finite_difference.jl:55; finite_difference(::Calculus.##1...\n",
+       "   20  .../finite_difference.jl:27; finite_difference(::Calculus.##1...\n",
+       "   3   .../finite_difference.jl:0; finite_difference(::Calculus.##1...\n",
+       "  5   .../finite_difference.jl:0; finite_difference_hessian(::Func...\n"
       ]
      },
-     "execution_count": 7,
+     "execution_count": 6,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -358,6 +338,69 @@
     "See `?flat` for more options."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "#### Comparing results\n",
+    "\n",
+    "Pass two `ProfileData` objects to `flat` to compare them. The third column is simply the difference between the first two."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<table class=\"data-frame\"><thead><tr><th></th><th>count_pct_1</th><th>count_pct_2</th><th>count_pct_diff</th><th>function</th></tr></thead><tbody><tr><th>1</th><td>19.57</td><td>17.39</td><td>-2.18</td><td>Calculus.finite_difference_hessian</td></tr><tr><th>2</th><td>53.91</td><td>54.42</td><td>0.51</td><td>Calculus.derivative</td></tr><tr><th>3</th><td>14.67</td><td>14.4</td><td>-0.27</td><td>Calculus.finite_difference</td></tr><tr><th>4</th><td>99.57</td><td>99.59</td><td>0.02</td><td>Calculus.second_derivative</td></tr><tr><th>5</th><td>99.89</td><td>99.9</td><td>0.01</td><td>IJulia.execute_request</td></tr><tr><th>6</th><td>99.89</td><td>99.9</td><td>0.01</td><td>include_string</td></tr><tr><th>7</th><td>99.89</td><td>99.9</td><td>0.01</td><td>IJulia.eventloop</td></tr><tr><th>8</th><td>99.89</td><td>99.9</td><td>0.01</td><td>IJulia.#14</td></tr><tr><th>9</th><td>99.89</td><td>99.9</td><td>0.01</td><td>FProfile.MissingInfo.missing_info</td></tr></tbody></table>"
+      ],
+      "text/plain": [
+       "9×4 DataFrames.DataFrame\n",
+       "│ Row │ count_pct_1 │ count_pct_2 │ count_pct_diff │\n",
+       "├─────┼─────────────┼─────────────┼────────────────┤\n",
+       "│ 1   │ 19.57       │ 17.39       │ -2.18          │\n",
+       "│ 2   │ 53.91       │ 54.42       │ 0.51           │\n",
+       "│ 3   │ 14.67       │ 14.4        │ -0.27          │\n",
+       "│ 4   │ 99.57       │ 99.59       │ 0.02           │\n",
+       "│ 5   │ 99.89       │ 99.9        │ 0.01           │\n",
+       "│ 6   │ 99.89       │ 99.9        │ 0.01           │\n",
+       "│ 7   │ 99.89       │ 99.9        │ 0.01           │\n",
+       "│ 8   │ 99.89       │ 99.9        │ 0.01           │\n",
+       "│ 9   │ 99.89       │ 99.9        │ 0.01           │\n",
+       "\n",
+       "│ Row │ function                           │\n",
+       "├─────┼────────────────────────────────────┤\n",
+       "│ 1   │ Calculus.finite_difference_hessian │\n",
+       "│ 2   │ Calculus.derivative                │\n",
+       "│ 3   │ Calculus.finite_difference         │\n",
+       "│ 4   │ Calculus.second_derivative         │\n",
+       "│ 5   │ IJulia.execute_request             │\n",
+       "│ 6   │ include_string                     │\n",
+       "│ 7   │ IJulia.eventloop                   │\n",
+       "│ 8   │ IJulia.#14                         │\n",
+       "│ 9   │ FProfile.MissingInfo.missing_info  │"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "pd2 = @fprofile 1000000 second_derivative(sin, 1.0)\n",
+    "flat(pd, pd2, combineby=:function)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Of course, this is most useful when comparing different algorithms or commits (see [Revise.jl](https://github.com/timholy/Revise.jl)). The differences in the above table are  just noise."
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -375,32 +418,32 @@
     {
      "data": {
       "text/plain": [
-       " 981 ./task.jl:335; (::IJulia.##14#17)()\n",
-       "  981 ...Julia/src/eventloop.jl:8; eventloop(::ZMQ.Socket)\n",
-       "   981 ...rc/execute_request.jl:154; execute_request(::ZMQ.Socket, ::...\n",
-       "    981 ...Compat/src/Compat.jl:464; include_string(::Module, ::Stri...\n",
-       "     981 ./loading.jl:515; include_string(::String, ::String)\n",
-       "      981 ./<missing>:?; FProfile.MissingInfo.missing_info\n",
-       "       981 ...ile/src/FProfile.jl:52; FProfile.MissingInfo.missing_info\n",
-       "        981 ./profile.jl:23; FProfile.MissingInfo.missing_info\n",
-       "         980 ...ile/src/FProfile.jl:67; FProfile.MissingInfo.missing_info\n",
-       "          977 .../src/derivative.jl:71; second_derivative(::Function...\n",
-       "           227 ...ite_difference.jl:224; finite_difference_hessian(:...\n",
-       "            159 ...ite_difference.jl:55; finite_difference(::Calculu...\n",
-       "             52 ...ite_difference.jl:55; finite_difference(::Base.#...\n",
-       "              41 ./math.jl:419; FProfile.MissingInfo.missi...\n",
-       "             22 ...ite_difference.jl:27; finite_difference(::Base.#...\n",
-       "             1  ...ite_difference.jl:0; finite_difference(::Base.#...\n",
-       "             1  ...ite_difference.jl:48; finite_difference(::Base.#...\n",
+       " 919 ./task.jl:335; (::IJulia.##14#17)()\n",
+       "  919 ...Julia/src/eventloop.jl:8; eventloop(::ZMQ.Socket)\n",
+       "   919 ...rc/execute_request.jl:154; execute_request(::ZMQ.Socket, ::...\n",
+       "    919 ...Compat/src/Compat.jl:464; include_string(::Module, ::Stri...\n",
+       "     919 ./loading.jl:515; include_string(::String, ::String)\n",
+       "      919 ./<missing>:?; FProfile.MissingInfo.missing_info\n",
+       "       919 ...ile/src/FProfile.jl:52; FProfile.MissingInfo.missing_info\n",
+       "        919 ./profile.jl:23; FProfile.MissingInfo.missing_info\n",
+       "         917 ...ile/src/FProfile.jl:67; FProfile.MissingInfo.missing_info\n",
+       "          913 .../src/derivative.jl:71; second_derivative(::Function...\n",
+       "           490 ...src/derivative.jl:3; derivative(::Function, ::Sy...\n",
+       "           175 ...ite_difference.jl:224; finite_difference_hessian(:...\n",
+       "            112 ...ite_difference.jl:55; finite_difference(::Calculu...\n",
+       "             2  ...ite_difference.jl:0; finite_difference(::Base.#...\n",
+       "             32 ...ite_difference.jl:27; finite_difference(::Base.#...\n",
+       "             64 ...ite_difference.jl:55; finite_difference(::Base.#...\n",
+       "              55 ./math.jl:419; FProfile.MissingInfo.missi...\n",
+       "               1 ./math.jl:300; FProfile.MissingInfo.missi...\n",
        "             1  ./math.jl:300; finite_difference(::Base.#...\n",
+       "             1  ...ite_difference.jl:48; finite_difference(::Base.#...\n",
        "             1  ...ite_difference.jl:54; finite_difference(::Base.#...\n",
-       "            29  ...ite_difference.jl:27; finite_difference(::Calculu...\n",
-       "            3   ...ite_difference.jl:54; finite_difference(::Calculu...\n",
-       "            4   ...ite_difference.jl:0; finite_difference(::Calculu...\n",
-       "           462 ...src/derivative.jl:3; derivative(::Function, ::Sy...\n",
-       "           12  ...src/derivative.jl:0; derivative(::Function, ::Sy...\n",
-       "           2   ...ite_difference.jl:0; finite_difference_hessian(:...\n",
-       "          1   .../src/derivative.jl:0; second_derivative(::Function...\n",
+       "            20  ...ite_difference.jl:27; finite_difference(::Calculu...\n",
+       "            3   ...ite_difference.jl:0; finite_difference(::Calculu...\n",
+       "           5   ...ite_difference.jl:0; finite_difference_hessian(:...\n",
+       "           5   ...src/derivative.jl:0; derivative(::Function, ::Sy...\n",
+       "          3   .../src/derivative.jl:0; second_derivative(::Function...\n",
        " 1   ...lus/src/derivative.jl:0; derivative(::Function, ::Symbol, ...\n"
       ]
      },
@@ -422,22 +465,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 18,
+   "execution_count": 9,
    "metadata": {},
    "outputs": [
     {
      "data": {
       "text/plain": [
-       " 981 IJulia\n",
-       "  981 Compat\n",
-       "   981 Base\n",
-       "    981 FProfile.MissingInfo\n",
-       "     978 Calculus\n",
-       "      41 FProfile.MissingInfo\n",
+       " 919 IJulia\n",
+       "  919 Compat\n",
+       "   919 Base\n",
+       "    919 FProfile.MissingInfo\n",
+       "     916 Calculus\n",
+       "      55 FProfile.MissingInfo\n",
        " 1   Calculus\n"
       ]
      },
-     "execution_count": 18,
+     "execution_count": 9,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -450,7 +493,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "If you're interested in a particular module/file/method/function, you can pass it to `tree`, along with an optional _neighborhood range_."
+    "If you're only interested in a particular module/file/method/function, you can pass it to `tree`, along with an optional _neighborhood range_."
    ]
   },
   {
@@ -461,13 +504,13 @@
     {
      "data": {
       "text/plain": [
-       " 978 ...rofile/src/FProfile.jl:67; FProfile.MissingInfo.missing_info\n",
-       "  977 ...lus/src/derivative.jl:71; second_derivative(::Function, ::F...\n",
-       "   227 .../finite_difference.jl:224; finite_difference_hessian(::Func...\n",
-       "   462 ...lus/src/derivative.jl:3; derivative(::Function, ::Symbol,...\n",
-       "   12  ...lus/src/derivative.jl:0; derivative(::Function, ::Symbol,...\n",
-       "   2   .../finite_difference.jl:0; finite_difference_hessian(::Func...\n",
-       "  1   ...lus/src/derivative.jl:0; second_derivative(::Function, ::F...\n"
+       " 916 ...rofile/src/FProfile.jl:67; FProfile.MissingInfo.missing_info\n",
+       "  913 ...lus/src/derivative.jl:71; second_derivative(::Function, ::F...\n",
+       "   490 ...lus/src/derivative.jl:3; derivative(::Function, ::Symbol,...\n",
+       "   175 .../finite_difference.jl:224; finite_difference_hessian(::Func...\n",
+       "   5   .../finite_difference.jl:0; finite_difference_hessian(::Func...\n",
+       "   5   ...lus/src/derivative.jl:0; derivative(::Function, ::Symbol,...\n",
+       "  3   ...lus/src/derivative.jl:0; second_derivative(::Function, ::F...\n"
       ]
      },
      "execution_count": 10,
@@ -494,11 +537,11 @@
     {
      "data": {
       "text/plain": [
-       "977 ...ulus/src/derivative.jl:71; second_derivative(::Function, ::Fl...\n",
-       " 227 .../finite_difference.jl:224; finite_difference_hessian(::Funct...\n",
-       " 462 ...lus/src/derivative.jl:3; derivative(::Function, ::Symbol, ...\n",
-       " 12  ...lus/src/derivative.jl:0; derivative(::Function, ::Symbol, ...\n",
-       " 2   .../finite_difference.jl:0; finite_difference_hessian(::Funct...\n"
+       "913 ...ulus/src/derivative.jl:71; second_derivative(::Function, ::Fl...\n",
+       " 490 ...lus/src/derivative.jl:3; derivative(::Function, ::Symbol, ...\n",
+       " 175 .../finite_difference.jl:224; finite_difference_hessian(::Funct...\n",
+       " 5   .../finite_difference.jl:0; finite_difference_hessian(::Funct...\n",
+       " 5   ...lus/src/derivative.jl:0; derivative(::Function, ::Symbol, ...\n"
       ]
      },
      "execution_count": 11,
@@ -518,7 +561,7 @@
     "\n",
     "(if you want to build your own analysis)\n",
     "\n",
-    "The raw Profile data is available either through `Base.Profile.retrieve()`, or through `pd.data` and `pd.lidict`. However, you might find `FProfile.backtraces(::ProfileData)` more immediately useful. "
+    "The raw profiler data is available either through `Base.Profile.retrieve()`, or through `pd.data` and `pd.lidict`. However, you might find `FProfile.backtraces(::ProfileData)` more immediately useful. "
    ]
   },
   {
@@ -536,7 +579,7 @@
     {
      "data": {
       "text/plain": [
-       "10-element Array{StackFrame,1}:\n",
+       "11-element Array{StackFrame,1}:\n",
        " (::IJulia.##14#17)() at task.jl:335                                  \n",
        " eventloop(::ZMQ.Socket) at eventloop.jl:8                            \n",
        " execute_request(::ZMQ.Socket, ::IJulia.Msg) at execute_request.jl:154\n",
@@ -546,7 +589,8 @@
        " macro expansion at FProfile.jl:52 [inlined]                          \n",
        " macro expansion at profile.jl:23 [inlined]                           \n",
        " macro expansion at FProfile.jl:67 [inlined]                          \n",
-       " second_derivative(::Function, ::Float64) at derivative.jl:71         "
+       " second_derivative(::Function, ::Float64) at derivative.jl:71         \n",
+       " derivative(::Function, ::Symbol, ::Symbol) at derivative.jl:3        "
       ]
      },
      "execution_count": 12,
diff --git a/README.md b/README.md
index b1b1d02..1946c65 100644
--- a/README.md
+++ b/README.md
@@ -6,9 +6,8 @@
 
 [![codecov.io](http://codecov.io/github/cstjean/FProfile.jl/coverage.svg?branch=master)](http://codecov.io/github/cstjean/FProfile.jl?branch=master)
 
-FProfile.jl is a nicer interface for Julia's [sampling
-profiler](https://docs.julialang.org/en/latest/manual/profile/). It defines a few
-profiling metrics not available in `Base.Profile`'s reports.
+FProfile.jl provides more fully-featured reports for Julia's [sampling
+profiler](https://docs.julialang.org/en/latest/manual/profile/). 
 
 # Manual
 
@@ -19,4 +18,4 @@ profiling metrics not available in `Base.Profile`'s reports.
 - [ProfileView.jl](https://github.com/timholy/ProfileView.jl) is a really good way to
   visualize profiling data.
 - [TraceCalls.jl](http://nbviewer.jupyter.org/github/cstjean/TraceCalls.jl/blob/master/README.ipynb#Profiling) can be useful to track down memory allocations and type-stability issues.
-
+- [StatProfiler.jl](https://github.com/tkluck/StatProfilerHTML.jl)
\ No newline at end of file
diff --git a/src/FProfile.jl b/src/FProfile.jl
index 4b256dc..9cb3051 100644
--- a/src/FProfile.jl
+++ b/src/FProfile.jl
@@ -448,7 +448,7 @@ function flat(btraces::BackTraces;
     @assert !isempty(keys) "ProfileData contains no applicable traces"
     ntrace = sum(first, btraces)
     perc(var::Symbol, counts) =
-        (percent ? Symbol(var, "_percent") => round.(counts ./ ntrace * 100, 2) :
+        (percent ? Symbol(var, "_pct") => round.(counts ./ ntrace * 100, 2) :
          var => counts)
     count_cols = [perc(:count, [count_dict[sf] for sf in keys])]
     if _module !== nothing
@@ -461,12 +461,11 @@ function flat(btraces::BackTraces;
                                 if is_applicable(f, first(keys))]...))
     if _module !== nothing; df = df[[m in _module for m in df[:module]], :] end
     if !inlined; df = df[!is_inlined.(df[:stackframe]), :] end
-    return sort(df, cols=percent ? :count_percent : :count, rev=true)
+    return sort(df, cols=percent ? :count_pct : :count, rev=true)
 end
 
 flat(pd::ProfileData, _module::Tuple; kwargs...) = 
     flat(pd; kwargs..., _module=_module)
-
 flat(pd::ProfileData, _module::Module; kwargs...) = 
     flat(pd; kwargs..., _module=(_module,))
 
@@ -477,4 +476,42 @@ df_combineby(df::DataFrame) =
 tree(pd::ProfileData, df::DataFrame, nrow::Int, neighborhood::UnitRange=-1:1) =
     tree(pd, df[nrow, df_combineby(df)], neighborhood)
 
+################################################################################
+# Comparisons
+
+function my_outer_join(df1, df2, on::Vector)
+    # See DataFrames.jl#1270 for why this is necessary
+    kept = setdiff(names(df1), on)
+    row_vals(df, i) = map(last, DataFrameRow(df, i))
+    mk_dict(df) = Dict(row_vals(df, i)=>i for i in 1:size(df, 1))
+    dict1 = mk_dict(df1[:, on])
+    dict2 = mk_dict(df2[:, on])
+    df_keys = unique(vcat(df1, df2)[on])
+    build_col(df, dict, col) = [haskey(dict, row_vals(df_keys, i)) ?
+                                df[dict[row_vals(df_keys, i)], col] : 0
+                                for i in 1:size(df_keys, 1)]
+    df_kept = DataFrame()
+    for col in kept
+        col1, col2 = Symbol(col, :_1), Symbol(col, :_2)
+        df_kept[col1] = build_col(df1, dict1, col)
+        df_kept[col2] = build_col(df2, dict2, col)
+        df_kept[Symbol(col, :_diff)] = round.(df_kept[col2] .- df_kept[col1], 2)
+    end
+    return hcat(df_kept, df_keys)
+end
+
+
+function flat(pd1::ProfileData, pd2::ProfileData; _module=nothing, kwargs...)
+    df1 = flat(pd1; _module=_module, kwargs...)
+    df2 = flat(pd2; _module=_module, kwargs...)
+    combineby_ind = _module === nothing ? 2 : 3
+    df = FProfile.my_outer_join(df1, df2, names(df1)[combineby_ind:end])
+    return sort(df, cols=names(df)[3], by=abs, rev=true)::Any
+end
+
+flat(pd1::ProfileData, pd2::ProfileData, _module::Tuple; kwargs...) = 
+    flat(pd1, pd2; kwargs..., _module=_module)
+flat(pd1::ProfileData, pd2::ProfileData, _module::Module; kwargs...) = 
+    flat(pd1, pd2; kwargs..., _module=(_module,))
+
 end # module