Access data directly

[parsley]

Hi,

I'm trying to automatically access some data that you would usually display via the Tableviewers in S4L via my Python script. For example, after a lot of trial and error, I found the way to extract the psSAR via something like

	average_sar_field_evaluator = analysis.em_evaluators.AverageSarFieldEvaluator(inputs=inputs)
	average_sar_field_evaluator.TargetMass = 10.0, Unit("g")
	average_sar_field_evaluator.UpdateAttributes()
	document.AllAlgorithms.Add(average_sar_field_evaluator)
	
	# perform the actual computation, throw an exception if an error occurs
	assert average_sar_field_evaluator.Update(), 'ERROR, failed to compute SAR'

	dictionary=average_sar_field_evaluator.Outputs[1].Data.DataJson

psSAR=json.loads(dictionary)['simple_data_collection']['data_collection']['PeakValue']['data']

Now, I'd also like to extract the reflection coefficient but I only got to

em_sensor_extractor.Outputs["Reflection Coefficient(f)"].Data

which does not return the numbers. How do I access it? Is there a general method or some place in the documentation that explains how to access the outputs of different algorithms?

Thanks!

[halder]

Hi, you can try something like the following to extract the reflection coefficient. You can always try to build extraction manually once and select "To python" by right-clicking on the end of the tree (i.e. the component you extract from your pipeline)

import numpy
import s4l_v1.analysis as analysis
import s4l_v1.document as document
import s4l_v1.model as model
import s4l_v1.units as units
from s4l_v1 import ReleaseVersion
from s4l_v1 import Unit

sim_name = "MRI Volume Coil Cleg = 29.5 pF" ###### define the sim name in this case this is a multiport FDTD simulation

Adding a new EmMultiPortSimulationExtractor

simulation = document.AllSimulations[sim_name]
em_multi_port_simulation_extractor = simulation.Results()

this is extracting a port

inputs = [em_multi_port_simulation_extractor.Outputs["MRI Volume Coil Cleg = 29.5 pF - Endring source 1 (Birdcage 1)"]]
em_port_simulation_extractor = analysis.extractors.EmPortSimulationExtractor(inputs=inputs)
em_port_simulation_extractor.Name = "MRI Volume Coil Cleg = 29.5 pF - Endring source 1 (Birdcage 1)"
em_port_simulation_extractor.UpdateAttributes()
document.AllAlgorithms.Add(em_port_simulation_extractor)

em_sensor_extractor = em_port_simulation_extractor["Endring source 1 (Birdcage 1)"]
document.AllAlgorithms.Add(em_sensor_extractor)

ref_coef_data = em_sensor_extractor.Outputs["Reflection Coefficient(f)"]
ref_coef_data.Update()
freqlist = ref_coef_data.Data.Axis
ref_coef = refCoeff.Data.GetComponent(0)
ref_coef_magnitude = np.sqrt(np.real(ref_coef)**2 + np.imag(ref_coef)**2)
import matplotlib.pyplot as plt

plt.plot(freqlist,ref_coef_magnitude)