diff --git a/.gitignore b/.gitignore
index 02882d3..feee3ff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -49,3 +49,5 @@ pkg
 
 .RData
 .Rhistory
+
+*.dataset
diff --git a/lib/ms/lipid/search.rb b/lib/ms/lipid/search.rb
index d2e099d..d4e680e 100644
--- a/lib/ms/lipid/search.rb
+++ b/lib/ms/lipid/search.rb
@@ -1,48 +1,92 @@
 require 'ms/spectrum'
 require 'rserve/simpler'  # TODO: move to integrated interface with rserve when available
 require 'core_ext/array/in_groups'
+require 'ms/lipid/search/hit'
 
 module MS
   class Lipid
     class Search
+
+      # A Search::Bin is a range that contains the *entire* query spectrum
+      # (not just the portion covered by the range).  the query spectrum, and
+      # an EVD that describes the probability that a peak's delta to nearest
+      # peak is that small by chance.
+      class Bin < Range
+        # the intensity value of the query spectrum should be a query
+        attr_accessor :query_spectrum
+        attr_accessor :evd
+
+        def initialize(range_obj, query_spectrum)
+          super(range_obj.begin, range_obj.end, range_obj.exclude_end?)
+          @query_spectrum = query_spectrum
+        end
+
+        # returns the nearest num_hits MS::Lipid::Search::Hits sorted by delta
+        # [with tie going to the lower m/z]
+        def nearest_hits(mz, num_hits=1)
+          mzs = @query_spectrum.mzs
+          queries = @query_spectrum.intensities
+          index = @query_spectrum.find_nearest_index(mz)
+          _min = index - (num_nearest-1)
+          (_min >= 0) || (_min = 0)
+          _max = index + (num_nearest-1)
+          (_max < @query_spectrum.size) || (_max = @query_spectrum - 1)
+          delta_index_pairs = (_min.._max).map {|i| [mz.-(mzs[i]).abs, i] }.sort[0, num_to_return]
+          # this could be improved by updating the evd if it happens to jump
+          # to the next major Search::Bin
+          # of course, this has the advantage that the next nearest peaks will
+          # have the same probability distribution as the nearest peak.
+
+          delta_index_pairs.map do |delta, index|
+            hit = Hit.new( :query => queries[index], :observed_mz => mz)
+            dev = (evd.type == :ppm) ? hit.ppm : hit.delta.abs
+            hit.pvalue = evd.pvalue(dev)
+            hit
+          end
+        end
+
+        def to_range
+          Range.new( self.begin, self.end, self.exclude_end? )
+        end
+      end
+
       class EVD
+        DEFAULT_TYPE = :ppm
         EVD_R = Rserve::Simpler.new
-        attr_accessor :location, :scale, :shape
         # takes location, scale and shape parameters
-        def initialize(location, scale, shape)
+        attr_accessor :location, :scale, :shape
+        # type is :ppm or :amu
+        attr_accessor :type
+        def initialize(location, scale, shape, type=DEFAULT_TYPE)
           @location, @scale, @shape = location, scale, shape
+          @type = type
         end
-        # takes a ppm and returns the pvalue
-        # note that it will take the 
-        def pvalue(ppm)
-          EVD_R.converse "pgev(log(#{ppm}), #{@location}, #{@scale}, #{@shape})"
+
+        # takes a deviation and returns the pvalue
+        def pvalue(dev)
+          EVD_R.converse "pgev(log(#{dev}), #{@location}, #{@scale}, #{@shape})"
         end
 
-        # returns an EVD object
-        def self.ppms_to_evd(ppms)
-          %w(ismev evd).each do |lib|
-            reply = EVD_R.converse "library(#{lib})"
-            puts "REAPLY: #{reply}"
-            unless reply.size > 4  # ~roughly
-              $stderr.puts "The libraries ismev and evd must be installed in your R env!"
-              $stderr.puts "From within R:"
-              $stderr.puts %Q{install.packages("ismev") ; install.packages("evd")}
-              raise "must have R (rserve) and ismev and evd installed!"
-            end
+        def self.require_r_library(lib)
+          reply = EVD_R.converse "library(#{lib})"
+          puts "REAPLY: #{reply}"
+          unless reply.size > 4  # ~roughly
+            $stderr.puts "The libraries ismev and evd must be installed in your R env!"
+            $stderr.puts "From within R (works best if R is started with sudo or root for installing):"
+            $stderr.puts %Q{install.packages("ismev") ; install.packages("evd")}
+            raise "must have R (rserve) and ismev and evd installed!"
           end
-          #ppmsl = ppms.map {|v| Math::log(v) }
-          #p EVD_R.converse("cor(c(1,2,3), c(4,4,6))", :ppmsl_r => ppmsl )
-          #params = EVD_R.converse("hist(ppms_r, 50)", :ppms_r => ppms )
-          params = EVD_R.converse("m <- gev.fit(log(ppms_r)); c(m$mle[1], m$mle[2], m$mle[3])", :ppms_r => ppms )
-          #EVD_R.command("svggev.diag(m)")
-          #EVD_R.pause
-          EVD.new(*params)
         end
-            #ppmsl = log(ppms)
-            #gev.fit(ppmsl)
-        # pgev(log10(#{TEST_PVAL}), model$mle[1], model$mle[2], model$mle[3])
 
+        # returns an EVD object
+        def self.deviations_to_evd(type, devs)
+          %w(ismev evd).each {|lib| require_r_library(lib) }
+          params = EVD_R.converse("m <- gev.fit(log(devs_r))\n c(m$mle[1], m$mle[2], m$mle[3])", :devs_r => devs )
+          EVD.new(*params, type)
+        end
       end
+
+
       STANDARD_MODIFICATIONS = {
         :proton => [1,2],
         :ammonium => [1],
@@ -101,14 +145,13 @@ def create_search_spectrum(queries)
         MS::Spectrum.new([mzs, query_groups])
       end
 
-
-
       def create_probability_function(queries, opts={})
         opts = STANDARD_SEARCH.merge( opts )
 
-        spec = create_search_spectrum(queries)
+        query_spectrum = create_search_spectrum(queries)
+
         # make sure we get the right bin size based on the input
-        ss = spec.mzs.size ; optimal_num_groups = 1
+        ss = query_spectrum.mzs.size ; optimal_num_groups = 1
         (1..ss).each do |divisions|
           if  (ss.to_f / divisions) >= opts[:prob_min_bincnt]
             optimal_num_groups = divisions
@@ -116,33 +159,28 @@ def create_probability_function(queries, opts={})
           end
         end
 
-        rng = Random.new
-        # create a mock spectrum of intensity 1
         mz_ranges = []
-        evds = spec.peaks.in_groups(optimal_num_groups,false).map do |peaks|
-          mz_range = Range.new( peaks.first.first, peaks.last.first )
-          mz_ranges << mz_range
-          random_mzs = opts[:num_rand_samples_per_bin].times.map { rng.rand(mz_range) }
-          puts "*****************************"
-          puts "MZRANGE: "
-          p mz_range
+        last_peaks_group = nil
+        search_bins = query_spectrum.peaks.in_groups(optimal_num_groups,false).each_cons(2).map do |peaks1, peaks2|
+          bin = MS::Lipid::Search::Bin.new( Range.new(peaks1.first.first, peaks2.first.first, true), query_spectrum )
+          last_peaks_group = peaks2
+          bin
+        end
+        _range = Range.new(last_peaks_group.first.first, last_peaks_group.last.first)
+        search_bins << MS::Lipid::Search::Bin.new(_range, query_spectrum) # inclusive
+
+        search_bins.map do |search_bin| 
+          rng = Random.new
+          random_mzs = opts[:num_rand_samples_per_bin].times.map { rng.rand(search_bin.to_range)  }
           # find the deltas
           diffs = random_mzs.map do |random_mz| 
-            nearest_random_mz = spec.find_all_nearest(random_mz).first
+            nearest_random_mz = query_spectrum.find_nearest(random_mz)
             delta = (random_mz - nearest_random_mz).abs
             opts[:ppm] ? delta./(nearest_random_mz).*(1e6) : delta
           end
-          #File.write("data_#{mz_range}.dataset", "deltas\n" + diffs.join("\n"))
-          EVD.ppms_to_evd(diffs)
-        end
-        File.open("plot_evd_params_ppm_#{!!opt[:ppm]}.data",'w') do |out|
-          out.puts %w(mzrange loc scale shape).join("\t")
-          evds.zip(mz_ranges) do |evd, range|
-            out.puts [range, evd.location, evd.scale, evd.shape].join("\t")
-          end
+          EVD.deviations_to_evd(diffs, (opts[:ppm] ? :ppm : :amu))
         end
       end
-
     end
   end
 end