[MRG] plot a random subsample with 'sourmash plot --subsample'.

doc/command-line.rst

@@ -112,6 +112,8 @@ Options::
   --indices -- turn off index display on the plot.
   --vmax -- maximum value (default 1.0) for heatmap.
   --vmin -- minimum value (deafult 0.0) for heatmap.
+  --subsample=<N> -- plot a maximum of <N> samples, randomly chosen.
+  --subsample-seed=<seed> -- seed for pseudorandom number generator.
 
 Example figures:
 

sourmash_lib/commands.py

@@ -310,6 +310,8 @@ def compare(args):
 
     # load in the various signatures
     siglist = []
+    ksizes = set()
+    moltypes = set()
     for filename in args.signatures:
         notify('loading {}', filename, end='\r')
         loaded = sig.load_signatures(filename, select_ksize=args.ksize,
@@ -319,26 +321,39 @@ def compare(args):
             notify('\nwarning: no signatures loaded at given ksize/molecule type from {}', filename)
         siglist.extend(loaded)
 
-    notify(' '*79, end='\r')
-    notify('loaded {} signatures total.'.format(len(siglist)))
+        # track ksizes/moltypes
+        for s in loaded:
+            ksizes.add(s.minhash.ksize)
+            moltypes.add(sourmash_args.get_moltype(s))
+
+        # error out while loading if we have more than one ksize/moltype
+        if len(ksizes) > 1 or len(moltypes) > 1:
+            break
 
     # check ksizes and type
-    ksizes = set([s.minhash.ksize for s in siglist])
     if len(ksizes) > 1:
         error('multiple k-mer sizes loaded; please specify one with -k.')
         ksizes = sorted(ksizes)
         error('(saw k-mer sizes {})'.format(', '.join(map(str, ksizes))))
         sys.exit(-1)
 
-    moltypes = set([sourmash_args.get_moltype(x) for x in siglist])
     if len(moltypes) > 1:
         error('multiple molecule types loaded; please specify --dna, --protein')
         sys.exit(-1)
 
+    notify(' '*79, end='\r')
+    notify('loaded {} signatures total.'.format(len(siglist)))
+
     # check to make sure they're potentially compatible - either using
     # max_hash/scaled, or not.
     scaled_sigs = [s.minhash.max_hash for s in siglist]
     is_scaled = all(scaled_sigs)
+    is_scaled_2 = any(scaled_sigs)
+
+    # complain if it's not all one or the other
+    if is_scaled != is_scaled_2:
+        error('cannot mix scaled signatures with bounded signatures')
+        sys.exit(-1)
 
     # if using --scaled, downsample appropriately
     if is_scaled:
@@ -410,13 +425,20 @@ def plot(args):
     # set up cmd line arguments
     parser = argparse.ArgumentParser()
     parser.add_argument('distances', help="output from 'sourmash compare'")
-    parser.add_argument('--pdf', action='store_true')
-    parser.add_argument('--labels', action='store_true')
-    parser.add_argument('--indices', action='store_false')
+    parser.add_argument('--pdf', action='store_true',
+                        help='output PDF, not PNG.')
+    parser.add_argument('--labels', action='store_true',
+                        help='show sample labels on dendrogram/matrix')
+    parser.add_argument('--indices', action='store_false',
+                        help='show sample indices but not labels')
     parser.add_argument('--vmax', default=1.0, type=float,
-                        help='(default: %(default)f)')
+                        help='upper limit of heatmap scale; (default: %(default)f)')
     parser.add_argument('--vmin', default=0.0, type=float,
-                        help='(default: %(default)f)')
+                        help='lower limit of heatmap scale; (default: %(default)f)')
+    parser.add_argument("--subsample", type=int,
+                        help="randomly downsample to this many samples, max.")
+    parser.add_argument("--subsample-seed", type=int, default=1,
+                        help="random seed for --subsample; default=1")
     args = parser.parse_args(args)
 
     # load files
@@ -445,7 +467,20 @@ def plot(args):
     ax1.set_xticks([])
     ax1.set_yticks([])
 
-    Y = sch.linkage(D, method='single') # cluster!
+    # subsample?
+    if args.subsample:
+        numpy.random.seed(args.subsample_seed)
+
+        sample_idx = list(range(len(labeltext)))
+        numpy.random.shuffle(sample_idx)
+        sample_idx = sample_idx[:args.subsample]
+
+        np_idx = numpy.array(sample_idx)
+        D = D[numpy.ix_(np_idx, np_idx)]
+        labeltext = [ labeltext[idx] for idx in sample_idx ]
+
+    ### do clustering
+    Y = sch.linkage(D, method='single')
     Z1 = sch.dendrogram(Y, orientation='right', labels=labeltext)
     fig.savefig(dendrogram_out)
     notify('wrote dendrogram to: {}', dendrogram_out)

tests/test_sourmash.py

@@ -765,6 +765,60 @@ def test_do_plot_comparison_3():
         assert os.path.exists(os.path.join(location, "cmp.matrix.png"))
 
 
+def test_plot_subsample_1():
+    with utils.TempDirectory() as location:
+        testdata1 = utils.get_test_data('genome-s10.fa.gz.sig')
+        testdata2 = utils.get_test_data('genome-s11.fa.gz.sig')
+        testdata3 = utils.get_test_data('genome-s12.fa.gz.sig')
+        testdata4 = utils.get_test_data('genome-s10+s11.sig')
+        inp_sigs = [testdata1, testdata2, testdata3, testdata4]
+
+        status, out, err = utils.runscript('sourmash',
+                                           ['compare'] + inp_sigs + \
+                                           ['-o', 'cmp', '-k', '21', '--dna'],
+                                           in_directory=location)
+
+        status, out, err = utils.runscript('sourmash',
+                                           ['plot', 'cmp',
+                                            '--subsample', '3'],
+                                           in_directory=location)
+
+        print(out)
+
+        expected = """\
+0\ts10+s11
+1\tgenome-s12.fa.gz
+2\tgenome-s10.fa.gz"""
+        assert expected in out
+
+
+def test_plot_subsample_2():
+    with utils.TempDirectory() as location:
+        testdata1 = utils.get_test_data('genome-s10.fa.gz.sig')
+        testdata2 = utils.get_test_data('genome-s11.fa.gz.sig')
+        testdata3 = utils.get_test_data('genome-s12.fa.gz.sig')
+        testdata4 = utils.get_test_data('genome-s10+s11.sig')
+        inp_sigs = [testdata1, testdata2, testdata3, testdata4]
+
+        status, out, err = utils.runscript('sourmash',
+                                           ['compare'] + inp_sigs + \
+                                           ['-o', 'cmp', '-k', '21', '--dna'],
+                                           in_directory=location)
+
+        status, out, err = utils.runscript('sourmash',
+                                           ['plot', 'cmp',
+                                            '--subsample', '3',
+                                            '--subsample-seed=2'],
+                                           in_directory=location)
+
+        print(out)
+        expected = """\
+0\tgenome-s12.fa.gz
+1\ts10+s11
+2\tgenome-s11.fa.gz"""
+        assert expected in out
+
+
 def test_search_sig_does_not_exist():
     with utils.TempDirectory() as location:
         testdata1 = utils.get_test_data('short.fa')