Per #1735, print a warning message is the continuous filtering logic …

…results in 0 matched pairs. Also, match existing logic to NOT WRITE any output, not even header rows, when the output AsciiTable contains no results.

met/src/tools/core/stat_analysis/aggr_stat_line.cc

@@ -3506,7 +3506,15 @@ void mpr_to_cnt(STATAnalysisJob &job, const AggrMPRInfo &info,
    //
    // If there are no matched pairs to process, return
    //
-   if(pd_thr.f_na.n() == 0 || pd_thr.o_na.n() == 0) return;
+   if(pd_thr.f_na.n() == 0 || pd_thr.o_na.n() == 0) {
+      mlog << Warning << "\nmpr_to_cnt() -> "
+           << "no MPR lines retained for -out_fcst_thresh "
+           << job.out_fcst_thresh[i_thresh].get_str() << " -out_obs_thresh "
+           << job.out_obs_thresh[i_thresh].get_str() << " -out_cnt_logic "
+           << setlogic_to_string(job.out_cnt_logic)
+           << "\n\n";
+      return;
+   }
 
    //
    // Set the precip flag based on fcst_var and obs_var
@@ -3566,7 +3574,15 @@ void mpr_to_psum(STATAnalysisJob &job, const AggrMPRInfo &info,
    //
    // If there are no matched pairs to process, return
    //
-   if(pd_thr.f_na.n() == 0 || pd_thr.o_na.n() == 0) return;
+   if(pd_thr.f_na.n() == 0 || pd_thr.o_na.n() == 0) {
+      mlog << Warning << "\nmpr_to_psum() -> "
+           << "no MPR lines retained for -out_fcst_thresh "
+           << job.out_fcst_thresh[i_thresh].get_str() << " -out_obs_thresh "
+           << job.out_obs_thresh[i_thresh].get_str() << " -out_cnt_logic "
+           << setlogic_to_string(job.out_cnt_logic)
+           << "\n\n";
+      return;
+   }
 
    //
    // Initialize counts

met/src/tools/core/stat_analysis/stat_analysis_job.cc

@@ -3329,6 +3329,11 @@ void write_job_aggr_mpr(STATAnalysisJob &job, STATLineType lt,
       }
    } // end for it
 
+   //
+   // Discard contents of an empty AsciiTable
+   //
+   if(r == 1) at.clear();
+
    return;
 }
 
@@ -4201,6 +4206,11 @@ void setup_table(AsciiTable &at, int n_hdr_cols, int prec) {
 
 void write_table(AsciiTable &at, ofstream *sa_out) {
 
+   //
+   // Do not write an empty table
+   //
+   if(at.nrows() == 0 && at.ncols() == 0) return;
+
    if(sa_out) *(sa_out) << at << "\n" << flush;
    else       cout      << at << "\n" << flush;