libpsdxx [FEATURE]: provide additional function to map complex data

src/libs/libpsdxx/function_lin_log_sampling.cc

@@ -28,11 +28,12 @@
  *
  * REVISIONS and CHANGES 
  *  - 14/02/2019   V1.0   Thomas Forbriger
+ *  - 08/04/2019   V1.1   provide version for complex data too
  * 
  * ============================================================================
  */
 #define PSDXX_FUNCTION_LIN_LOG_SAMPLING_CC_VERSION \
-  "PSDXX_FUNCTION_LIN_LOG_SAMPLING_CC   V1.0"
+  "PSDXX_FUNCTION_LIN_LOG_SAMPLING_CC   V1.1"
 
 #include <psdxx/psd.h>
 #include <psdxx/error.h>
@@ -60,6 +61,29 @@ namespace psd {
     //                       const TDseries::Tcoc& flin,
     //                       const TDseries::Tcoc& flog)
 
+  /* ---------------------------------------------------------------------- */
+
+  TDCseries log_sampling(const TDCseries::Tcoc& s,
+                         const TDseries::Tcoc& flin,
+                         const TDseries::Tcoc& flog)
+  {
+    // consistency checks
+    PSDXX_assert(s.size()>1, "input series must contain at least 2 values");
+    PSDXX_assert(s.size()==flin.size(),
+                 "series of frequencies does not match data series");
+    double df1=flin(flin.f()+1)-flin(flin.f());
+    double df2=flin(flin.l())-flin(flin.l()-1);
+    PSDXX_assert(std::abs((df2/df1)-1.)<1.e-8,
+                 "input frequency scale is not linear");
+    TDCISeries::Tcoc data;
+    data.interval=df1;
+    data.data=s;
+    TDCseries retval=log_sampling(data, flog);
+    return(retval);
+  } // TDCseries log_sampling(const TDCseries::Tcoc& s,
+    //                        const TDseries::Tcoc& flin,
+    //                        const TDseries::Tcoc& flog)
+
 } // namespace psd
 
 /* ----- END OF function_lin_log_sampling.cc ----- */

src/libs/libpsdxx/psd.h

@@ -27,6 +27,7 @@
  *
  * REVISIONS and CHANGES 
  *  - 01/01/2019   V1.0   Thomas Forbriger
+ *  - 08/04/2019   V1.1   provide additional version to map complex data
  * 
  * ============================================================================
  */
@@ -35,7 +36,7 @@
 #ifndef PSDXX_PSD_H_VERSION
 
 #define PSDXX_PSD_H_VERSION \
-  "PSDXX_PSD_H   V1.0"
+  "PSDXX_PSD_H   V1.1"
 
 #include<complex>
 #include<aff/series.h>
@@ -356,6 +357,21 @@ namespace psd {
                          const TDseries::Tcoc& flin,
                          const TDseries::Tcoc& flog);
 
+   /*! sample complex values on a logarithmic frequency axis
+    *
+    * \param s spectral values with uniform sampling along frequency axis
+    * \param flin frequency values on a linear scale, matching the input
+    *             series \p s
+    * \param flog frequency values on a logarithmic scale like returned by
+    *          function log_frequency()
+    * \return series of sampled spectral values, where each sample of the
+    *         returned series corresponds to the frequency with the
+    *         corresponding index in \p flog
+    */
+   TDCseries log_sampling(const TDCseries::Tcoc& s,
+                          const TDseries::Tcoc& flin,
+                          const TDseries::Tcoc& flog);
+
 } // namespace psd
 
 #endif // PSDXX_PSD_H_VERSION (includeguard)