adding statistics to curve fitted line

fff94100 · Peter Jansweijer · e93c6d63 · fff94100
Commit fff94100 authored Jul 16, 2018 by Peter Jansweijer
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Showing with 9 additions and 3 deletions

analyze_sellmeier.py sw/insitu_alpha/analyze_sellmeier.py +9 -3

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--- a/sw/insitu_alpha/analyze_sellmeier.py
+++ b/sw/insitu_alpha/analyze_sellmeier.py
@@ -509,7 +509,12 @@ def analyze_plot(insitu_file, analyse_single, x, y, name, tolerance, use_itu_cha
    
    # first order linear fit:
    popt_clean, pcov_clean = curve_fit(line, x_clean, y_clean)
+    #perr_clean = numpy.sqrt(numpy.diag(pcov_clean))
+    #print("a =", popt_clean[0], "+/-", pcov_clean[0,0]**0.5)
+    #print("b =", popt_clean[1], "+/-", pcov_clean[1,1]**0.5)
+    
    tangent = popt_clean[0]  # in [ps]/[nm]
+    tangent_stdev = pcov_clean[0,0]**0.5  # in [ps]/[nm]
    tangent_array = numpy.append(tangent_array,tangent)
    # for this particular tangent measurement, take the mean value of the 
    # temperatures during the measurement.
@@ -567,11 +572,11 @@ def analyze_plot(insitu_file, analyse_single, x, y, name, tolerance, use_itu_cha
    if use_itu_channels:
      ax.set_title("CRTT versus ITU Channel number")
      ax.set_xlabel('ITU Channel number')
-      ax.text(0.01, 0.85, "1st order linear tangent: " + str(tangent) + " [ps/ITU channel]", transform=ax.transAxes)
+      ax.text(0.01, 0.85, "1st order linear tangent: " + '{:5.3f}'.format(tangent) + " +/- " + '{:5.3f}'.format(tangent_stdev) + " [ps/ITU channel]", transform=ax.transAxes)
    else:
      ax.set_title("CRTT versus wavelength")
      ax.set_xlabel('Wavelenth [nm]')
-      ax.text(0.01, 0.85, "1st order linear tangent: " + str(tangent) + " [ps/nm]", transform=ax.transAxes)
+      ax.text(0.01, 0.85, "1st order linear tangent: " + '{:5.3f}'.format(tangent) + " +/- " + '{:5.3f}'.format(tangent_stdev) + " [ps/nm]", transform=ax.transAxes)
    
    with_tolerances = False
    ax.text(0.01, 0.95, str(insitu_file), transform=ax.transAxes)
@@ -739,7 +744,7 @@ def analyze_plot(insitu_file, analyse_single, x, y, name, tolerance, use_itu_cha
      alpha_file.write("file: " + insitu_file + "\n")
      alpha_file.write("reference file/directory: " + ref_name + "\n")
      alpha_file.write("outlier-count: " + str(outlier_cnt) + "\n")
-      alpha_file.write("first order linear fit tangent: " + str(tangent)+ " [ps]/[nm]\n")
+      alpha_file.write("first order linear fit tangent: " + '{:5.3f}'.format(tangent) + " +/- " + '{:5.3f}'.format(tangent_stdev) + " [ps]/[nm]\n")
      alpha_file.write("============================\n")
      alpha_file.write("ITU_Channel, Lambda, alpha_sellmeier, aplha_sellmeier(SPEC format), alpha_tangent, alpha_sellmeier-alpha_tangent, temperature\n")
      for i in range(len(x_clean)):
@@ -1036,6 +1041,7 @@ if __name__ == "__main__":
    
  if ref_name != '':
    y = crtt_array - ref_crtt_array
+    y_stdev = numpy.sqrt(crtt_array_std**2 + ref_crtt_array_std**2)
  else:
    y = crtt_array