[segyio] 239/376: Remove scale_samples; store samples as float

[Jørgen Kvalsvik]

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jokva-guest pushed a commit to branch debian
in repository segyio.

commit 03cb5b23b39b2f5dca3eeade0349e88452e833f5
Author: Jørgen Kvalsvik <jokva at statoil.com>
Date:   Tue Mar 14 09:13:03 2017 +0100

    Remove scale_samples; store samples as float
    
    The heuristic that separates between time/depth is broken, since the
    sample rate for depth is millimeters, not meters. In other words, it is
    impossible to figure out just by inspecting the file if sample interval
    means time or depth. The entire tool is removed in favour of correctly
    storing the samples as floats.
---
 python/segyio/create.py |  2 +-
 python/segyio/open.py   |  2 +-
 python/segyio/tools.py  | 30 ------------------------------
 python/test/tools.py    | 19 -------------------
 4 files changed, 2 insertions(+), 51 deletions(-)

diff --git a/python/segyio/create.py b/python/segyio/create.py
index 15918aa..bada70d 100644
--- a/python/segyio/create.py
+++ b/python/segyio/create.py
@@ -69,7 +69,7 @@ def create(filename, spec):
     """
     f = segyio.SegyFile(filename, "w+")
 
-    f._samples       = numpy.asarray(spec.samples, dtype = numpy.intc)
+    f._samples       = numpy.asarray(spec.samples, dtype = numpy.single)
     f._ext_headers   = spec.ext_headers
     f._bsz           = _segyio.trace_bsize(len(f.samples))
 
diff --git a/python/segyio/open.py b/python/segyio/open.py
index 04f9222..82d238c 100644
--- a/python/segyio/open.py
+++ b/python/segyio/open.py
@@ -68,7 +68,7 @@ def open(filename, mode="r", iline=189, xline=193, strict = True):
         t0 = f.header[0][segyio.TraceField.DelayRecordingTime]
         sample_count = metrics['sample_count']
         f._samples = numpy.array([t0 + i * dt for i in range(sample_count)],
-                                 dtype = numpy.intc)
+                                 dtype = numpy.single) / 1000.0
 
     except:
         f.close()
diff --git a/python/segyio/tools.py b/python/segyio/tools.py
index f334dba..9b40960 100644
--- a/python/segyio/tools.py
+++ b/python/segyio/tools.py
@@ -121,33 +121,3 @@ def cube(f):
     smps = len(f.samples)
     dims = (fast, slow, smps) if offs == 1 else (fast, slow, offs, smps)
     return f.trace.raw[:].reshape(dims)
-
-def scale_samples(samples):
-    """ Guess unit and scale of the sample intervals
-
-    :type samples: iterable[int]
-    :rtype: tuple[numpy.ndarray,str]
-
-    Attempt to figure out if the sample values represent depth (in meters) or
-    time (in milliseconds).
-    """
-
-    samples = np.array(samples)
-
-    # this is VERY unlikely, but in the case of a file with only one sample per
-    # trace, assume depth (meter)
-    if len(samples) == 1:
-        return (samples, 'm')
-
-    # heuristic: since the spec suggests microseconds for step between samples,
-    # and 4ms is *very* common for step size, any large difference between two
-    # values probably means that the unit is time. A step size of 100 meters is
-    # quite unlikely, but this threshold is arbitrary and might require tuning
-    # in the future
-    depth = abs(samples[0] - samples[1]) < 100
-
-    if not depth:
-        samples = samples / 1000
-
-    unit = 'm' if depth else 'ms'
-    return (samples, unit)
diff --git a/python/test/tools.py b/python/test/tools.py
index 5c98588..f2f2f75 100644
--- a/python/test/tools.py
+++ b/python/test/tools.py
@@ -94,22 +94,3 @@ class ToolsTest(TestCase):
             dims = (len(f.ilines), len(f.xlines), len(f.offsets), len(f.samples))
             x = segyio.tools.collect(f.trace[:]).reshape(dims)
             self.assertTrue(np.all(x == segyio.tools.cube(f)))
-
-    def test_scale_samples(self):
-        with segyio.open(self.filename) as f:
-            samples, unit = segyio.tools.scale_samples(f.samples)
-            self.assertEqual('ms', unit)
-            self.assertListEqual([4.0 * i for i in range(len(samples))],
-                                 list(samples))
-
-            meters = [10 * i for i in range(len(samples))]
-            f._samples = np.array(meters)
-            samples, unit = segyio.tools.scale_samples(f.samples)
-            self.assertEqual('m', unit)
-            self.assertListEqual(meters, list(samples))
-
-    def test_scale_samples_pylist(self):
-        sampleslist = [10 * i for i in range(10)]
-        samplesnp = np.array(sampleslist)
-        eq = np.all(samplesnp == segyio.tools.scale_samples(samplesnp)[0])
-        self.assertTrue(eq)

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