Heatmap plot in sobol analysis with groups

[nikithiel]

Hey there,

First of all, thanks for the great package! It integrates well into my coding project and helps me a lot.

R.n. I'm doing a Sobol analysis using grouping of my 24 input parameters. When I call problem.heatmap() after the analysis, I get the following heatmap, which I guess isn't exactly the right behavior:

The heatmap shows the results for groups 2, 1, 3 and 4, but the labels are incorrect. In heatmap.py, heatmap() uses the following as x-axis labels:

SALib/src/SALib/plotting/heatmap.py

Lines 71 to 77 in ee5e2cf

	# Get unique groups (if defined) while maintaining order of group names
	disp_names = sp["groups"]
	if disp_names is None:
	disp_names = sp["names"]
	ax.xaxis.set_ticks(range(0, len(disp_names)))
	ax.xaxis.set_ticklabels(disp_names, rotation=90)

I think the correct behavior would be something like this:

groups = _check_groups(problem)

if not groups:
    namesGSA = problem['names']
else:
    namesGSA, _ = extract_group_names(groups)

Let me know what you think about it. Maybe I got something wrong here.

[ConnectedSystems]

Hi @nikithiel thanks for reporting this.

Is it possible to share a minimum working example? Or at least your problem specification? It would help confirm, or track down the cause.

Thank you!

[nikithiel]

Hey @ConnectedSystems,

I'm using SALib v1.4.7. I created a small MWE that is based on the example in .../examples/sobol/sobol.py. I change it slightly to work with ProblemSpec() and groups:

from SALib.test_functions import Ishigami
from SALib import ProblemSpec
import matplotlib.pyplot as plt

# Example from '.../examples/sobol/sobol.py' using ProblemSpec() class
# Parameters from '../../src/SALib/test_functions/params/Ishigami_groups.txt'
paramsSobol = {
    'names': ['x1', 'x2', 'x3'],
    'bounds': [[-3.14159265359, 3.14159265359], [-3.14159265359, 3.14159265359], [-3.14159265359, 3.14159265359]],
    'num_vars': 3,
    'groups': ['Group_1', 'Group_2', 'Group_2'],
    'dists': None,
    'sample_scaled': True
}

problem = ProblemSpec(
    {
        'num_vars': paramsSobol['num_vars'],
        'names': paramsSobol['names'],
        'bounds': paramsSobol['bounds'],
        'groups': paramsSobol['groups']
    }
)

problem.sample_sobol(1024, calc_second_order=True, skip_values=2048)
Y = Ishigami.evaluate(problem.samples)

problem.set_results(Y)
problem.analyze_sobol(calc_second_order=True, conf_level=0.95, print_to_console=True)
problem.heatmap()
plt.show()

Let me know, what you think.

[ConnectedSystems]

Hmmm, it works as expected for me on main (though there does seem to be an indexing issue with the plot).

from SALib.test_functions import Ishigami
from SALib import ProblemSpec
import matplotlib.pyplot as plt

# Example from '.../examples/sobol/sobol.py' using ProblemSpec() class
# Parameters from '../../src/SALib/test_functions/params/Ishigami_groups.txt'
problem = ProblemSpec(
    {
        'names': ['x1', 'x2', 'x3'],
        'bounds': [[-3.14159265359, 3.14159265359], [-3.14159265359, 3.14159265359], [-3.14159265359, 3.14159265359]],
        'num_vars': 3,
        'groups': ['Group_1', 'Group_2', 'Group_2'],
        'dists': None,
        'sample_scaled': True
    }
)

problem.sample_sobol(1024, calc_second_order=True, skip_values=2048)
problem.evaluate(Ishigami.evaluate)
problem.analyze_sobol(calc_second_order=True, conf_level=0.95, print_to_console=False)
problem.heatmap()
plt.show()

Could you try the most recent development version?

pip uninstall SALib
pip install git+https://github.com/SALib/SALib.git#egg=SALib

[ConnectedSystems]

Added a minor tweak to address the issue above:

[nikithiel]

Hey, thanks for checking the MWE. This indexing problem is exactly what I've meant. Results generally look the same for me.

[ConnectedSystems]

Hey, thanks for checking the MWE. This indexing problem is exactly what I've meant. Results generally look the same for me.

Oh okay, I misunderstood. I interpreted the G1, G2, ..., as the equivalent to x1, x2 etc, and that you were seeing groups being ignored.

The fix will be merged in shortly if you would like to try the dev version. I will release a patched version over the weekend.

[nikithiel]

Great. Thanks for the prompt fix!