Comments on logarithm function graph speeds

Contracts/pbrMathLogarithmTesting.sol

@@ -13,6 +13,14 @@ contract pbrMathLogarithmTesting {
   // ud(1 ether) = x.log2() = x.log10() = 0
   // Reverts with 999999999999999999
 
+  /// @notice Calculates the binary logarithm of the given signed number.
+  function unsignedLog10WithTenEther() external pure returns (UD60x18 result) {
+    UD60x18 x = ud(10 ether);
+    // Returns 1 ether, since: 
+    // 10 = 10**(1).
+    result = x.log10(); 
+  }
+
   /// @notice Calculates the binary logarithm of the given signed number.
   function unsignedLog2WithTenEther() external pure returns (UD60x18 result) {
     UD60x18 x = ud(10 ether);
@@ -22,11 +30,11 @@ contract pbrMathLogarithmTesting {
   }
 
   /// @notice Calculates the binary logarithm of the given signed number.
-  function unsignedLog10WithTenEther() external pure returns (UD60x18 result) {
-    UD60x18 x = ud(10 ether);
+  function unsignedLog2WithTwoEther() external pure returns (UD60x18 result) {
+    UD60x18 x = ud(2 ether);
     // Returns 1 ether, since: 
-    // 10 = 10**(1).
-    result = x.log10(); 
+    // 2 = 2**(1)
+    result = x.log2(); 
   }
 
   function unsignedLnWithEulersNumber() external pure returns (UD60x18 result) {
@@ -38,19 +46,23 @@ contract pbrMathLogarithmTesting {
     result = x.ln(); 
   }
 
-  /// @notice Calculates the log base 2 for the given signed number.
-  function unsignedLog2(UD60x18 x) external pure returns (UD60x18 result) {
-    result = x.log2();
+  /// @notice Calculates the log base 10 for the given signed number.
+  // Slowest growth logarithm function in pbr-math.
+  function unsignedLog10(UD60x18 x) external pure returns (UD60x18 result) {
+    result = x.log10();
   }
 
-  /// @notice Calculates the log base 10 for the given signed number.
+  /// @notice Calculates the log base e for the given signed number.
+  // Slower growth than log2 but faster than log10 in pbr-math.
   function unsignedLn(UD60x18 x) external pure returns (UD60x18 result) {
     result = x.ln();
   }
 
-  /// @notice Calculates the log base 10 for the given signed number.
-  function unsignedLog10(UD60x18 x) external pure returns (UD60x18 result) {
-    result = x.log10();
+  /// @notice Calculates the log base 2 for the given signed number.
+  // Fastest growth logarithm function in pbr-math.
+  // Slower than the square root function in pbr-math.
+  function unsignedLog2(UD60x18 x) external pure returns (UD60x18 result) {
+    result = x.log2();
   }
 
 }