libpsdxx [WP][FIX]: make reference function input arguments constant

src/libs/libpsdxx/function_lin_frequency.cc

@@ -39,7 +39,7 @@
 namespace psd {
 
    TDseries lin_frequency(const double& df, 
-                          unsigned int& nsamples)
+                          const unsigned int& nsamples)
    {
      PSDXX_assert(nsamples>0,
                   "at least one sample must be present");
@@ -50,7 +50,7 @@ namespace psd {
      }
      return(retval);
    } // TDseries lin_frequency(const double& df, 
-     //                        unsigned int& nsamples)
+     //                        const unsigned int& nsamples)
 
 
 } // namespace psd

src/libs/libpsdxx/function_log_frequency.cc

@@ -77,8 +77,8 @@ namespace psd {
     *
     */
    TDseries log_frequency(const double& df, 
-                          unsigned int& nsamples,
-                          unsigned int& n_per_decade)
+                          const unsigned int& nsamples,
+                          const unsigned int& n_per_decade)
    {
      PSDXX_assert(n_per_decade>0, "must be positive and finite");
      PSDXX_assert(nsamples>0, "must be positive and finite");
@@ -96,8 +96,8 @@ namespace psd {
      }
      return(retval);
    } // TDseries log_frequency(const double& df, 
-     //                        unsigned int& nsamples,
-     //                        unsigned int& n_per_decade)
+     //                        const unsigned int& nsamples,
+     //                        const unsigned int& n_per_decade)
 
 } // namespace psd
 

src/libs/libpsdxx/psd.h

@@ -219,7 +219,7 @@ namespace psd {
     * This function is a corresponding function to log_frequency().
     */
    TDseries lin_frequency(const double& df, 
-                          unsigned int& nsamples);
+                          const unsigned int& nsamples);
 
    /*! \brief return a logarithmic frequency scale
     *
@@ -235,8 +235,8 @@ namespace psd {
     * the actual sampling functions.
     */
    TDseries log_frequency(const double& df, 
-                          unsigned int& nsamples,
-                          unsigned int& n_per_decade);
+                          const unsigned int& nsamples,
+                          const unsigned int& n_per_decade);
 
    /*! sample values on a logarithmic frequency axis
     */