[Commit-gnuradio] [gnuradio] 03/08: channels: generate fading taps in blocks for minor speedup

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commit 5fb584806c62b4c4a441068ae8b8d5fad3703deb
Author: Tim O'Shea <address@hidden>
Date:   Sun Mar 27 11:11:40 2016 -0400

    channels: generate fading taps in blocks for minor speedup
---
 gr-channels/lib/fading_model_impl.cc           |  5 ++-
 gr-channels/lib/flat_fader_impl.cc             | 48 ++++++++++++++++----------
 gr-channels/lib/flat_fader_impl.h              |  1 +
 gr-channels/lib/selective_fading_model_impl.cc | 10 +++++-
 4 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/gr-channels/lib/fading_model_impl.cc 
b/gr-channels/lib/fading_model_impl.cc
index 721a43f..8e88efc 100644
--- a/gr-channels/lib/fading_model_impl.cc
+++ b/gr-channels/lib/fading_model_impl.cc
@@ -105,8 +105,11 @@ namespace gr {
     {
         const gr_complex* in = (const gr_complex*) input_items[0];
         gr_complex* out = (gr_complex*) output_items[0];
+        std::vector<gr_complex> ftaps;
+        d_fader.next_samples(ftaps, noutput_items);
         for(int i=0; i<noutput_items; i++){
-            out[i] = in[i] * d_fader.next_sample();
+            out[i] = in[i] * ftaps[i];
+            //out[i] = in[i] * d_fader.next_sample();
         }
         return noutput_items;
     }
diff --git a/gr-channels/lib/flat_fader_impl.cc 
b/gr-channels/lib/flat_fader_impl.cc
index f33ca22..b53e1da 100644
--- a/gr-channels/lib/flat_fader_impl.cc
+++ b/gr-channels/lib/flat_fader_impl.cc
@@ -70,26 +70,36 @@ namespace gr {
 #define _GRFASTCOS(x)   cos(x)
 #endif
 
-    gr_complex flat_fader_impl::next_sample(){
-        gr_complex H(0,0);
-        for(int n=1; n<d_N; n++){
-            float alpha_n = (2*M_PI*n - M_PI + d_theta)/(4*d_N);
-            d_psi[n+1] = fmod(d_psi[n+1] + 2*M_PI*d_fDTs*_GRFASTCOS(alpha_n), 
2*M_PI);
-            d_phi[n+1] = fmod(d_phi[n+1] + 2*M_PI*d_fDTs*_GRFASTCOS(alpha_n), 
2*M_PI);
-            float s_i = scale_sin*_GRFASTCOS(d_psi[n+1]);
-            float s_q = scale_sin*_GRFASTSIN(d_phi[n+1]);
-            H += gr_complex(s_i, s_q);
-            }
-
-        if(d_LOS){
-            d_psi[0] = fmod(d_psi[0] + 2*M_PI*d_fDTs*_GRFASTCOS(d_theta_los), 
2*M_PI);
-            float los_i = scale_los*_GRFASTCOS(d_psi[0]);
-            float los_q = scale_los*_GRFASTSIN(d_psi[0]);
-            H = H*scale_nlos + gr_complex(los_i,los_q);
-            }
+    void flat_fader_impl::next_samples(std::vector<gr_complex> &Hvec, int 
n_samples){
+        Hvec.resize(n_samples);
+        for(int i = 0; i < n_samples; i++){
+            gr_complex H(0,0);
+            for(int n=1; n<d_N; n++){
+                float alpha_n = (2*M_PI*n - M_PI + d_theta)/(4*d_N);
+                d_psi[n+1] = fmod(d_psi[n+1] + 
2*M_PI*d_fDTs*_GRFASTCOS(alpha_n), 2*M_PI);
+                d_phi[n+1] = fmod(d_phi[n+1] + 
2*M_PI*d_fDTs*_GRFASTCOS(alpha_n), 2*M_PI);
+                float s_i = scale_sin*_GRFASTCOS(d_psi[n+1]);
+                float s_q = scale_sin*_GRFASTSIN(d_phi[n+1]);
+                H += gr_complex(s_i, s_q);
+                }
+    
+            if(d_LOS){
+                d_psi[0] = fmod(d_psi[0] + 
2*M_PI*d_fDTs*_GRFASTCOS(d_theta_los), 2*M_PI);
+                float los_i = scale_los*_GRFASTCOS(d_psi[0]);
+                float los_q = scale_los*_GRFASTSIN(d_psi[0]);
+                H = H*scale_nlos + gr_complex(los_i,los_q);
+                }
+    
+            update_theta();
+            Hvec[i] = H;
+        }
+        
+    }
 
-        update_theta();
-        return H;
+    gr_complex flat_fader_impl::next_sample(){
+        std::vector<gr_complex> v(1);
+        next_samples(v,1);
+        return v[0];
     }
 
     void flat_fader_impl::update_theta()
diff --git a/gr-channels/lib/flat_fader_impl.h 
b/gr-channels/lib/flat_fader_impl.h
index ae782ff..3a086f3 100644
--- a/gr-channels/lib/flat_fader_impl.h
+++ b/gr-channels/lib/flat_fader_impl.h
@@ -75,6 +75,7 @@ namespace gr {
 
         flat_fader_impl(unsigned int N, float fDTs, bool LOS, float K, int 
seed);
         gr_complex next_sample();
+        void next_samples(std::vector<gr_complex> &HVec, int n_samples);
 
     }; /* class flat_fader_impl */
   } /* namespace channels */
diff --git a/gr-channels/lib/selective_fading_model_impl.cc 
b/gr-channels/lib/selective_fading_model_impl.cc
index dfd7b74..be9c0b1 100644
--- a/gr-channels/lib/selective_fading_model_impl.cc
+++ b/gr-channels/lib/selective_fading_model_impl.cc
@@ -82,6 +82,13 @@ namespace gr {
         const gr_complex* in = (const gr_complex*) input_items[0];
         gr_complex* out = (gr_complex*) output_items[0];
 
+        // pregenerate fading components
+        std::vector<std::vector<gr_complex> > fading_taps;
+        for(size_t j=0; j<d_faders.size(); j++){
+            fading_taps.push_back( std::vector<gr_complex>() );
+            d_faders[j]->next_samples(fading_taps[j], noutput_items);
+            }
+
         // loop over each output sample
         for(int i=0; i<noutput_items; i++){
 
@@ -92,7 +99,8 @@ namespace gr {
 
             // add each flat fading component to the taps
             for(size_t j=0; j<d_faders.size(); j++){
-                gr_complex ff_H(d_faders[j]->next_sample());
+                gr_complex ff_H(fading_taps[j][i]);
+                //gr_complex ff_H(d_faders[j]->next_sample());
                 for(size_t k=0; k<d_taps.size(); k++){
                     float dist = k-d_delays[j];
                     float interpmag = d_sintable.sinc(2*M_PI*dist);