Import GIT HEAD of openEMS sub-project (with Python interface)

1 files changed, 66 insertions, 0 deletions

diff --git a/openEMS/python/openEMS/utilities.py b/openEMS/python/openEMS/utilities.py
new file mode 100644
index 0000000..22bfbf6
--- /dev/null
+++ b/openEMS/python/openEMS/utilities.py
@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2015,20016 Thorsten Liebig (Thorsten.Liebig@gmx.de)
+#
+# This program 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 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import numpy as np
+
+def DFT_time2freq( t, val, freq, signal_type='pulse'):
+    assert len(t)==len(val)
+    assert len(freq)>0
+    f_val = np.zeros(len(freq))*1j
+    for n_f in range(len(freq)):
+        f_val[n_f] = np.sum( val*np.exp( -1j*2*np.pi*freq[n_f] * t ) )
+
+    if signal_type == 'pulse':
+        f_val *= t[1]-t[0]
+    elif signal_type == 'periodic':
+        f_val /= len(t)
+    else:
+        raise Exception('Unknown signal type: "{}"'.format(signal_type))
+
+    return 2*f_val  # single-sided spectrum
+
+def Check_Array_Equal(a,b, tol, relative=False):
+    a = np.array(a)
+    b = np.array(b)
+    if a.shape!=b.shape:
+        return False
+    if tol==0:
+        return (a==b).all()
+    if relative:
+        d = np.abs((a-b)/a)
+    else:
+        d = np.abs((a-b))
+    return np.max(d)<tol
+
+if __name__=="__main__":
+    import pylab as plt
+
+    t = np.linspace(0,2,201)
+
+    s = np.sin(2*np.pi*2*t)
+    plt.plot(t,s)
+
+    f = np.linspace(0,3,101)
+    sf = DFT_time2freq(t, s, f, 'periodic')
+
+    plt.figure()
+    plt.plot(f, np.abs(sf))
+
+    plt.show()
+
+