# HG changeset patch
# User Jeff Hammel <k0scist@gmail.com>
# Date 1409889696 25200
# Node ID 7517682843cb86d6bced5cb579233fe0d5ea32f8
# Parent  6906e5fc6dfd04eaa3460220f78c1cd7b99b87c7
CLI

diff -r 6906e5fc6dfd -r 7517682843cb numerics/interpolation.py
--- a/numerics/interpolation.py	Thu Sep 04 20:57:10 2014 -0700
+++ b/numerics/interpolation.py	Thu Sep 04 21:01:36 2014 -0700
@@ -5,7 +5,7 @@
 interpolation
 """
 
-__all__ = ['neighbors', 'linear_interpolation']
+__all__ = ['neighbors', 'linear_interpolation', 'InterpolateParser']
 
 def neighbors(start, finish):
     """
@@ -65,4 +65,68 @@
         retval.append(ratio*data[right][1] + (1.-ratio)*data[left][1])
     return retval
 
+class InterpolateParser(argparse.ArgumentParser):
+    """CLI option parser"""
 
+    def __init__(self, **kwargs):
+        kwargs.setdefault('description', __doc__)
+        argparse.ArgumentParser.__init__(self, **kwargs)
+        self.add_argument('input', nargs='?',
+                          type=argparse.FileType('r'), default=sys.stdin,
+                          help='input file, or read from stdin if ommitted')
+        self.add_argument('-o', '--output', dest='output',
+                          type=argparse.FileType('w'), default=sys.stdout,
+                          help="output file, or stdout if ommitted")
+        self.add_argument('--points', '--print-points', dest='print_points',
+                          action='store_true', default=False,
+                          help="print the points to interpolate to and exit")
+        self.options = None
+
+    def parse_args(self, *args, **kw):
+        options = argparse.ArgumentParser.parse_args(self, *args, **kw)
+        self.validate(options)
+        self.options = options
+        return options
+
+    def validate(self, options):
+        """validate options"""
+
+def main(args=sys.argv[1:]):
+    """CLI"""
+
+    # parse command line options
+    parser = InterpolateParser()
+    options = parser.parse_args(args)
+
+    # read the CSV
+    reader = csv.reader(options.input)
+    data = [[float(col) for col in row] for row in reader]
+    ncols = set([len(row) for row in data])
+    assert len(ncols) == 1
+    ncols = ncols.pop()
+    assert ncols > 1
+
+    # get `x` values
+    data = sorted(data, key=lambda x: x[0])
+    x = [row[0] for row in data]
+    xmin = int(x[0]) + 1
+    xmax = int(x[-1])
+    points = range(xmin, xmax+1)
+    if options.print_points:
+        print ('\n'.join([str(point) for point in points]))
+        return
+
+    # make into x,y series
+    series = [[(row[0], row[col]) for row in data]
+              for col in range(1,ncols)]
+
+    # interpolate
+    interpolated = [linear_interpolation(s, points) for s in series]
+
+    # output interpolated data
+    writer = csv.writer(options.output)
+    for row in zip(points, *interpolated):
+        writer.writerow(row)
+
+if __name__ == '__main__':
+    main()