Fixed some incorrect comments (#4294)

* Fixed some incorrect comments

* Fixed some incorrect comments

* Fixed typo

openmmapi/include/openmm/CustomCompoundBondForce.h

@@ -326,15 +326,15 @@ public:
     /**
      * Get the parameters for a tabulated function that may appear in the energy expression.
      *
-     * @deprecated This method exists only for backward compatibility.  Use getTabulatedFunctionParameters() instead.
-     * If the specified function is not a Continuous1DFunction, this throws an exception.
+     * @deprecated This method exists only for backward compatibility.  Call getFunctionParameters() on the TabulatedFunction
+     * object instead.  If the specified function is not a Continuous1DFunction, this throws an exception.
      */
     void getFunctionParameters(int index, std::string& name, std::vector<double>& values, double& min, double& max) const;
     /**
      * Set the parameters for a tabulated function that may appear in the energy expression.
      *
-     * @deprecated This method exists only for backward compatibility.  Use setTabulatedFunctionParameters() instead.
-     * If the specified function is not a Continuous1DFunction, this throws an exception.
+     * @deprecated This method exists only for backward compatibility.  Call setFunctionParameters() on the TabulatedFunction
+     * object instead.  If the specified function is not a Continuous1DFunction, this throws an exception.
      */
     void setFunctionParameters(int index, const std::string& name, const std::vector<double>& values, double min, double max);
     /**

platforms/reference/src/SimTKReference/ReferencePME.cpp

@@ -367,15 +367,15 @@ pme_grid_spread_charge(pme_t pme, const vector<double>& charges)
         thetay  = &(pme->bsplines_theta[1][i*order]);
         thetaz  = &(pme->bsplines_theta[2][i*order]);
 
-        /* Loop over norder*norder*norder (typically 4*4*4) neighbor cells.
+        /* Loop over norder*norder*norder (typically 5*5*5) neighbor cells.
          *
          * As a neat optimization, we only spread in the forward direction, but apply PBC!
          *
-         * Since we are going to do an FFT on the grid, it doesnt matter where the data is,
+         * Since we are going to do an FFT on the grid, it doesn't matter where the data is,
          * in frequency space the result will be the same.
          *
          * So, the influence function (bsplines) will probably be something like (0.15,0.35,0.35,0.15),
-         * with largest weight 2-3 steps forward (you dont need to understand that for the implementation :-)
+         * with largest weight 2-3 steps forward (you don't need to understand that for the implementation :-)
          * Effectively, you can look at this as translating the entire grid.
          *
          * Why do we do this stupid thing?
@@ -672,7 +672,7 @@ pme_grid_interpolate_force(pme_t pme,
 
         /* See pme_grid_spread_charge() for comments about the order here, and only interpolation in one direction */
 
-        /* Since we will add order^3 (typically 4*4*4=64) terms to the force on each particle, we use temporary fx/fy/fz
+        /* Since we will add order^3 (typically 5*5*5=125) terms to the force on each particle, we use temporary fx/fy/fz
          * variables, and only add it to memory forces[] at the end.
          */
         for (ix=0;ix<order;ix++)