Worked on generic demodulation.

8 files changed, 321 insertions, 86 deletions

diff --git a/gnuradio-core/src/lib/general/Makefile.am b/gnuradio-core/src/lib/general/Makefile.am
index daa3c446e..861c82c28 100644
--- a/gnuradio-core/src/lib/general/Makefile.am
+++ b/gnuradio-core/src/lib/general/Makefile.am
@@ -53,7 +53,9 @@ libgeneral_la_SOURCES = 		\
 	gr_complex_to_xxx.cc		\
 	gr_conjugate_cc.cc		\
 	gr_copy.cc			\
+	gr_constellation.cc             \
 	gr_constellation_decoder_cb.cc	\
+	gr_constellation_receiver_cb.cc \
 	gr_correlate_access_code_bb.cc	\
 	gr_costas_loop_cc.cc		\
 	gr_count_bits.cc		\
@@ -100,7 +102,6 @@ libgeneral_la_SOURCES = 		\
 	gr_math.cc			\
 	gr_misc.cc			\
 	gr_mpsk_receiver_cc.cc		\
-	gr_constellation_receiver_cb.cc \
 	gr_nlog10_ff.cc			\
 	gr_nop.cc			\
 	gr_null_sink.cc			\
@@ -207,7 +208,9 @@ grinclude_HEADERS = 			\
 	gr_complex_to_interleaved_short.h \
 	gr_complex_to_xxx.h		\
 	gr_conjugate_cc.h		\
+	gr_constellation.h	        \
 	gr_constellation_decoder_cb.h	\
+	gr_constellation_receiver_cb.h	\
 	gr_copy.h			\
 	gr_correlate_access_code_bb.h	\
 	gr_costas_loop_cc.h		\
@@ -257,7 +260,6 @@ grinclude_HEADERS = 			\
 	gr_map_bb.h			\
 	gr_math.h			\
 	gr_misc.h			\
-	gr_constellation_receiver_cb.h	\
 	gr_nco.h			\
 	gr_nlog10_ff.h			\
 	gr_nop.h			\
@@ -378,7 +380,9 @@ swiginclude_HEADERS =			\
 	gr_complex_to_interleaved_short.i \
 	gr_complex_to_xxx.i		\
 	gr_conjugate_cc.i		\
+	gr_constellation.i	        \
 	gr_constellation_decoder_cb.i	\
+	gr_constellation_receiver_cb.i	\
 	gr_copy.i			\
 	gr_correlate_access_code_bb.i	\
 	gr_costas_loop_cc.i		\
@@ -419,7 +423,6 @@ swiginclude_HEADERS =			\
 	gr_lms_dfe_cc.i			\
 	gr_lms_dfe_ff.i			\
 	gr_map_bb.i			\
-	gr_constellation_receiver_cb.i	\
 	gr_nlog10_ff.i			\
 	gr_nop.i			\
 	gr_null_sink.i			\
diff --git a/gnuradio-core/src/lib/general/general.i b/gnuradio-core/src/lib/general/general.i
index f758211cc..47cc3b7fa 100644
--- a/gnuradio-core/src/lib/general/general.i
+++ b/gnuradio-core/src/lib/general/general.i
@@ -70,6 +70,7 @@
 #include <gr_throttle.h>
 #include <gr_mpsk_receiver_cc.h>
 #include <gr_constellation_receiver_cb.h>
+#include <gr_constellation.h>
 #include <gr_stream_mux.h>
 #include <gr_stream_to_streams.h>
 #include <gr_streams_to_stream.h>
@@ -192,6 +193,7 @@
 %include "gr_throttle.i"
 %include "gr_mpsk_receiver_cc.i"
 %include "gr_constellation_receiver_cb.i"
+%include "gr_constellation.i"
 %include "gr_stream_mux.i"
 %include "gr_stream_to_streams.i"
 %include "gr_streams_to_stream.i"
diff --git a/gnuradio-core/src/lib/general/gr_constellation.cc b/gnuradio-core/src/lib/general/gr_constellation.cc
new file mode 100644
index 000000000..03589dee8
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation.cc
@@ -0,0 +1,127 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <gr_io_signature.h>
+#include <gr_constellation.h>
+#include <gr_math.h>
+#include <gr_complex.h>
+
+gr_constellation_sptr 
+gr_make_constellation(std::vector<gr_complex> constellation)
+{
+  return gr_constellation_sptr(new gr_constellation (constellation));
+  }
+
+// Base Constellation Class
+
+gr_constellation::gr_constellation (std::vector<gr_complex> constellation) {
+  d_constellation = constellation;
+}
+
+
+unsigned int get_closest_point(std::vector<gr_complex> constellation, gr_complex sample) {
+
+  unsigned int table_size = constellation.size();
+  unsigned int min_index = 0;
+  float min_euclid_dist;
+  float euclid_dist;
+    
+  min_euclid_dist = norm(sample - constellation[0]); 
+  min_index = 0; 
+  for (unsigned int j = 1; j < table_size; j++){
+    euclid_dist = norm(sample - constellation[j]);
+    if (euclid_dist < min_euclid_dist){
+      min_euclid_dist = euclid_dist;
+      min_index = j;
+    }
+  }
+  return min_index;
+}
+
+// Chooses points base on shortest distance.
+// Inefficient.
+unsigned int gr_constellation::decision_maker(gr_complex sample)
+{
+  unsigned int min_index;
+  min_index = get_closest_point(d_constellation, sample);
+  return min_index;
+}
+
+gr_constellation_sector_sptr 
+gr_make_constellation_sector(std::vector<gr_complex> constellation,
+			     unsigned int real_sectors, unsigned int imag_sectors,
+			     float width_real_sectors, float width_imag_sectors)
+{
+  return gr_constellation_sector_sptr(new gr_constellation_sector (constellation, real_sectors, imag_sectors, width_real_sectors, width_imag_sectors));
+  }
+
+gr_constellation_sector::gr_constellation_sector (std::vector<gr_complex> constellation,
+						  unsigned int real_sectors, unsigned int imag_sectors,
+						  float width_real_sectors, float width_imag_sectors) :
+  gr_constellation(constellation),
+  n_sectors(real_sectors * imag_sectors),
+  n_real_sectors(real_sectors), n_imag_sectors(imag_sectors),
+  d_width_real_sectors(width_real_sectors), d_width_imag_sectors(width_imag_sectors)
+{
+  find_sector_values();
+}
+
+unsigned int gr_constellation_sector::decision_maker (gr_complex sample) {
+  unsigned int sector;
+  sector = get_sector(sample);
+  return sector_values[sector];
+}
+
+unsigned int gr_constellation_sector::get_sector (gr_complex sample) {
+  int real_sector, imag_sector;
+  unsigned int sector;
+  real_sector = int(real(sample)/d_width_real_sectors + n_real_sectors/2.0);
+  if (real_sector < 0) real_sector = 0;
+  if (real_sector >= n_real_sectors) real_sector = n_real_sectors-1;
+  imag_sector = int(imag(sample)/d_width_imag_sectors + n_imag_sectors/2.0);
+  if (imag_sector < 0) imag_sector = 0;
+  if (imag_sector >= n_imag_sectors) imag_sector = n_imag_sectors-1;
+  sector = real_sector * n_imag_sectors + imag_sector;
+  return sector;
+}
+  
+unsigned int gr_constellation_sector::calc_sector_value (unsigned int sector) {
+  unsigned int real_sector, imag_sector;
+  gr_complex sector_center;
+  unsigned int closest_point;
+  real_sector = float(sector)/n_imag_sectors;
+  imag_sector = sector - real_sector * n_imag_sectors;
+  sector_center = gr_complex((real_sector + 0.5 - n_real_sectors/2.0) * d_width_real_sectors,
+			     (imag_sector + 0.5 - n_imag_sectors/2.0) * d_width_imag_sectors);
+  closest_point = get_closest_point(d_constellation, sector_center);
+  return closest_point;
+}
+
+
+void gr_constellation_sector::find_sector_values () {
+  unsigned int i;
+  sector_values.clear();
+  for (i=0; i<n_sectors; i++) {
+    sector_values.push_back(calc_sector_value(i));
+  }
+}
+
diff --git a/gnuradio-core/src/lib/general/gr_constellation.h b/gnuradio-core/src/lib/general/gr_constellation.h
new file mode 100644
index 000000000..92ae3c5e2
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation.h
@@ -0,0 +1,108 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_GR_CONSTELLATION_H
+#define	INCLUDED_GR_CONSTELLATION_H
+
+#include <vector>
+#include <math.h>
+#include <gr_complex.h>
+#include <boost/enable_shared_from_this.hpp>
+
+class gr_constellation;
+typedef boost::shared_ptr<gr_constellation> gr_constellation_sptr;
+
+// public constructor
+gr_constellation_sptr 
+  gr_make_constellation (std::vector<gr_complex> constellation);
+
+class gr_constellation : public boost::enable_shared_from_this<gr_constellation>
+{
+ public:
+
+  gr_constellation (std::vector<gr_complex> constellation);
+  
+  //! Returns the set of points in this constellation.
+  std::vector<gr_complex> points() { return d_constellation;}
+  
+  //! Returns the constellation point that matches best.
+  //! Also calculates the phase error.
+  virtual unsigned int decision_maker (gr_complex sample);
+  
+  unsigned int bits_per_symbol () {
+    return floor(log(d_constellation.size())/log(2));
+  }
+
+  gr_constellation_sptr base() {
+    return shared_from_this();
+  }  
+
+ protected:
+
+  std::vector<gr_complex> d_constellation;
+  
+ private:
+  friend gr_constellation_sptr
+  gr_make_constellation (std::vector<gr_complex> constellation);
+};
+
+class gr_constellation_sector;
+typedef boost::shared_ptr<gr_constellation_sector> gr_constellation_sector_sptr;
+
+// public constructor
+gr_constellation_sector_sptr 
+gr_make_constellation_sector (std::vector<gr_complex> constellation, unsigned int real_sectors, unsigned int imag_sectors,
+			      float width_real_sectors, float width_imag_sectors);
+
+class gr_constellation_sector : public gr_constellation
+{
+ public:
+
+  gr_constellation_sector (std::vector<gr_complex> constellation, unsigned int real_sectors, unsigned int imag_sectors,
+			   float width_real_sectors, float width_imag_sectors);
+
+  unsigned int decision_maker (gr_complex sample);
+
+ protected:
+
+  virtual unsigned int get_sector (gr_complex sample);
+  
+  virtual unsigned int calc_sector_value (unsigned int sector);
+
+  void find_sector_values ();
+
+ private:
+
+  std::vector<unsigned int> sector_values;
+  unsigned int n_sectors;
+  unsigned int n_real_sectors;
+  unsigned int n_imag_sectors;
+  float d_width_real_sectors;
+  float d_width_imag_sectors;
+
+  friend gr_constellation_sector_sptr
+  gr_make_constellation_sector (std::vector<gr_complex> constellation, unsigned int real_sectors, unsigned int imag_sectors,
+			   float width_real_sectors, float width_imag_sectors);
+  
+};
+
+#endif
diff --git a/gnuradio-core/src/lib/general/gr_constellation.i b/gnuradio-core/src/lib/general/gr_constellation.i
new file mode 100644
index 000000000..bdc5436f2
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation.i
@@ -0,0 +1,62 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+%template(gr_complex_vector) std::vector<gr_complex>;
+%template(unsigned_int_vector) std::vector<unsigned int>;
+
+class gr_constellation;
+typedef boost::shared_ptr<gr_constellation> gr_constellation_sptr;
+%template(gr_constellation_sptr) boost::shared_ptr<gr_constellation>;
+%rename(constellation) gr_make_constellation;
+gr_constellation_sptr gr_make_constellation(std::vector<gr_complex> constellation);
+%ignore gr_constellation;
+
+class gr_constellation
+{
+public:
+  gr_constellation (std::vector<gr_complex> constellation);
+  std::vector<gr_complex> points();
+  unsigned int decision_maker (gr_complex sample);  
+  unsigned int bits_per_symbol ();
+  gr_constellation_sptr base ();
+};
+
+class gr_constellation_sector;
+typedef boost::shared_ptr<gr_constellation_sector> gr_constellation_sector_sptr;
+%template(gr_constellation_sector_sptr) boost::shared_ptr<gr_constellation_sector>;
+%rename(constellation_sector) gr_make_constellation_sector;
+gr_constellation_sector_sptr gr_make_constellation_sector(std::vector<gr_complex> constellation_sector,
+							  unsigned int real_sectors, unsigned int imag_sectors,
+							  float width_real_sectors, float width_imag_sectors);
+%ignore gr_constellation_sector;
+
+class gr_constellation_sector : public gr_constellation
+{
+public:
+  gr_constellation_sector (std::vector<gr_complex> constellation,
+			   unsigned int real_sectors, unsigned int imag_sectors,
+			   float width_real_sectors, float width_imag_sectors);
+  std::vector<gr_complex> points ();
+  unsigned int decision_maker (gr_complex sample);  
+  unsigned int bits_per_symbol ();
+  gr_constellation_sptr base ();
+};
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc
index 93af6d078..6520b66b2 100644
--- a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc
@@ -26,12 +26,11 @@
 
 #include <gr_io_signature.h>
 #include <gr_prefs.h>
+#include <gr_constellation.h>
 #include <gr_constellation_receiver_cb.h>
 #include <stdexcept>
 #include <gr_math.h>
 #include <gr_expj.h>
-// For debugging
-#include <iostream>
 
 
 #define M_TWOPI (2*M_PI)
@@ -41,7 +40,7 @@
 // Public constructor
 
 gr_constellation_receiver_cb_sptr 
-gr_make_constellation_receiver_cb(gr_constellation constell,
+gr_make_constellation_receiver_cb(gr_constellation_sptr constell,
 				  float alpha, float beta,
 				  float fmin, float fmax)
 {
@@ -49,10 +48,10 @@ gr_make_constellation_receiver_cb(gr_constellation constell,
 								      alpha, beta,
 								      fmin, fmax));
 }
-
+ 
 static int ios[] = {sizeof(char), sizeof(float), sizeof(float), sizeof(float)};
 static std::vector<int> iosig(ios, ios+sizeof(ios)/sizeof(int));
-gr_constellation_receiver_cb::gr_constellation_receiver_cb (gr_constellation constellation, 
+gr_constellation_receiver_cb::gr_constellation_receiver_cb (gr_constellation_sptr constellation, 
 							    float alpha, float beta,
 							    float fmin, float fmax)
   : gr_block ("constellation_receiver_cb",
@@ -61,12 +60,12 @@ gr_constellation_receiver_cb::gr_constellation_receiver_cb (gr_constellation con
     d_constellation(constellation), 
     d_alpha(alpha), d_beta(beta), d_freq(0), d_max_freq(fmax), d_min_freq(fmin), d_phase(0),
     d_current_const_point(0)
-{}
+{
+}
 
 void
 gr_constellation_receiver_cb::phase_error_tracking(float phase_error)
 {
-    
   d_freq += d_beta*phase_error;             // adjust frequency based on error
   d_phase += d_freq + d_alpha*phase_error;  // adjust phase based on error
 
@@ -82,7 +81,7 @@ gr_constellation_receiver_cb::phase_error_tracking(float phase_error)
 #if VERBOSE_COSTAS
   printf("cl: phase_error: %f  phase: %f  freq: %f  sample: %f+j%f  constellation: %f+j%f\n",
 	 phase_error, d_phase, d_freq, sample.real(), sample.imag(), 
-	 d_constellation.constellation()[d_current_const_point].real(), d_constellation.constellation()[d_current_const_point].imag());
+	 d_constellation->points()[d_current_const_point].real(), d_constellation->points()[d_current_const_point].imag());
 #endif
 }
 
@@ -112,9 +111,8 @@ gr_constellation_receiver_cb::general_work (int noutput_items,
     sample = in[i];
     nco = gr_expj(d_phase);   // get the NCO value for derotating the current sample
     sample = nco*sample;      // get the downconverted symbol
-    sym_value = d_constellation.decision_maker(sample);
-    phase_error = -arg(sample*conj(d_constellation.constellation()[sym_value]));
-    //std::cout << "sym_value: " << sym_value << " sample: " << sample << "phase_error: " << phase_error << std::endl;
+    sym_value = d_constellation->decision_maker(sample);
+    phase_error = -arg(sample*conj(d_constellation->points()[sym_value]));
     phase_error_tracking(phase_error);  // corrects phase and frequency offsets
     out[i] = sym_value;
     if(output_items.size() == 4) {
@@ -125,38 +123,7 @@ gr_constellation_receiver_cb::general_work (int noutput_items,
     i++;
   }
 
-  #if 0
-  printf("ninput_items: %d   noutput_items: %d   consuming: %d   returning: %d\n",
-	 ninput_items[0], noutput_items, i, i);
-  #endif
-
   consume_each(i);
   return i;
 }
 
-// Base Constellation Class
-
-gr_constellation::gr_constellation (std::vector<gr_complex> constellation) {
-  d_constellation = constellation;
-}
-
-// Chooses points base on shortest distance.
-// Inefficient.
-unsigned int gr_constellation::decision_maker(gr_complex sample)
-{
-  unsigned int table_size = constellation().size();
-  unsigned int min_index = 0;
-  float min_euclid_dist;
-  float euclid_dist;
-    
-  min_euclid_dist = norm(sample - constellation()[0]); 
-  min_index = 0; 
-  for (unsigned int j = 1; j < table_size; j++){
-    euclid_dist = norm(sample - constellation()[j]);
-    if (euclid_dist < min_euclid_dist){
-      min_euclid_dist = euclid_dist;
-      min_index = j;
-    }
-  }
-  return min_index;
-}
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
index ba38bdad6..d40d77fff 100644
--- a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
@@ -24,40 +24,17 @@
 #define	INCLUDED_GR_CONSTELLATION_RECEIVER_CB_H
 
 #include <gr_block.h>
+#include <gr_constellation.h>
 #include <gr_complex.h>
 #include <math.h>
 #include <fstream>
 
-class gr_constellation
-{
- public:
-
-  gr_constellation (std::vector<gr_complex> constellation);
-  
-  //! Returns the set of points in this constellation.
-  std::vector<gr_complex> constellation() { return d_constellation;}
-  
-  //! Returns the constellation point that matches best.
-  //! Also calculates the phase error.
-  unsigned int decision_maker (gr_complex sample);
-  
-  unsigned int bits_per_symbol () {
-    return floor(log(d_constellation.size())/log(2));
-  }
-  
- private:
-
-  std::vector<gr_complex> d_constellation;
-};
-
-class gri_mmse_fir_interpolator_cc;
-
 class gr_constellation_receiver_cb;
 typedef boost::shared_ptr<gr_constellation_receiver_cb> gr_constellation_receiver_cb_sptr;
 
 // public constructor
 gr_constellation_receiver_cb_sptr 
-gr_make_constellation_receiver_cb (gr_constellation constellation,
+gr_make_constellation_receiver_cb (gr_constellation_sptr constellation,
 				   float alpha, float beta,
 				   float fmin, float fmax);
 
@@ -136,7 +113,7 @@ protected:
    * The constructor also chooses which phase detector and decision maker to use in the work loop based on the
    * value of M.
    */
-  gr_constellation_receiver_cb (gr_constellation constellation, 
+  gr_constellation_receiver_cb (gr_constellation_sptr constellation, 
 				float alpha, float beta,
 				float fmin, float fmax);
 
@@ -151,7 +128,7 @@ protected:
   float d_freq, d_max_freq, d_min_freq;
   float d_phase;
 
-  gr_constellation d_constellation;
+  gr_constellation_sptr d_constellation;
   unsigned int d_current_const_point;
 
   //! delay line length.
@@ -164,7 +141,7 @@ protected:
   unsigned int d_dl_idx;
 
   friend gr_constellation_receiver_cb_sptr
-  gr_make_constellation_receiver_cb (gr_constellation constell,
+  gr_make_constellation_receiver_cb (gr_constellation_sptr constell,
 				     float alpha, float beta,
 				     float fmin, float fmax);
 };
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i
index b48322f45..2298d5099 100644
--- a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i
@@ -22,24 +22,13 @@
 
 GR_SWIG_BLOCK_MAGIC(gr,constellation_receiver_cb);
 
-%template(gr_complex_vector) std::vector<gr_complex>;
-
-class gr_constellation
-{
-public:
-  gr_constellation (std::vector<gr_complex> constellation);
-  std::vector<gr_complex> constellation();
-  unsigned int decision_maker (gr_complex sample);  
-  unsigned int bits_per_symbol ();
-};
-
-gr_constellation_receiver_cb_sptr gr_make_constellation_receiver_cb (gr_constellation constellation,
+gr_constellation_receiver_cb_sptr gr_make_constellation_receiver_cb (gr_constellation_sptr constellation,
 								     float alpha, float beta,
 								     float fmin, float fmax);
 class gr_constellation_receiver_cb : public gr_block
 {
  private:
-  gr_constellation_receiver_cb (gr_contellation constellation,
+  gr_constellation_receiver_cb (gr_contellation_sptr constellation,
 				float alpha, float beta,
 				float fmin, float fmax);
 public: