Strength of Influence and Sensitivity Analysis in jSmile

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JulianeMü
Posts: 4
Joined: Wed Jan 03, 2018 8:57 pm

Strength of Influence and Sensitivity Analysis in jSmile

Post by JulianeMü » Thu Jan 04, 2018 2:09 pm

Dear all,

is there any possibility to use the methods Sensitivity Analysis and Strength of influence in jSmile? Or is there any workaround?
For my work, I'm trying to find the most important nodes for the calculation of the specific target node.

I would be really thankful for your help!

Best regards,
Juliane

shooltz[BayesFusion]
Site Admin
Posts: 1247
Joined: Mon Nov 26, 2007 5:51 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by shooltz[BayesFusion] » Thu Jan 04, 2018 3:10 pm

Sensitivity analysis is only available from C++ SMILE (not from jSMILE)

Strength of influence is a feature implemented only in GeNIe.

JulianeMü
Posts: 4
Joined: Wed Jan 03, 2018 8:57 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by JulianeMü » Fri Jan 05, 2018 8:51 am

Thanks for the quick reply!

Is there any documentation about how the Sensitivity Analysis works? So, I can implement it by myself?

Best regards,
Juliane

shooltz[BayesFusion]
Site Admin
Posts: 1247
Joined: Mon Nov 26, 2007 5:51 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by shooltz[BayesFusion] » Fri Jan 05, 2018 4:35 pm

The sensitivity analysis chapter in SMILE docs is not ready yet. I'm including a simple function calling into SMILE to calculate the sensitivity of the PBC on age in the hepar model (included in GeNIe). Please read the GeNIe manual chapter titled "Sensitivity analysis in Bayesian networks" before proceeding; it contains the description of SMILE's implementation of sensitivity analysis, for which GeNIe only provides an user interface.

sensitivity.h in your SMILE directory contains the declaration of the sensitivity API. The names of the methods should be self-explaining, but of course we'll be happy to answer any questions you post here.

Code: Select all

int SensitivityExample()
{
	DSL_network net;
	int res = net.ReadFile(... hepar filename here ...);
	if (DSL_OKAY != res)
	{
		return res;
	}

	net.ClearAllTargets();

	int hTarget = net.FindNode("PBC");
	if (hTarget < 0)
	{
		return hTarget;
	}

	net.SetTarget(hTarget);

	// optionally set evidence here - sensitivity depends on the evidence

	DSL_sensitivity sens;
	res = sens.Calculate(net);
	if (DSL_OKAY != res)
	{
		return res;
	}

	// we're going to calculate how P(PBC=present) changes when the CPT of age changes
	int h = net.FindNode("age");
	if (h < 0)
	{
		return h;
	}

	std::vector<const DSL_Dmatrix *> coeffs;
	// zero in make_pair is the index of the 'present' state in PBC
	sens.GetCoefficients(h, std::make_pair(hTarget, 0), coeffs);
	if (coeffs.empty())
	{
		printf("Node has no effect on target with the current evidence.");
		return DSL_NO_ITEM;
	}
	
	// coeffs will have 4 DSL_Dmatrix objects for alpha, beta, gamma, delta
	// each DSL_Dmatrix has the same size
	// see GeNIe docs for the description of the coefficients
	int mtxElemCount = coeffs.front()->GetSize();
	for (int i = 0; i < mtxElemCount; i++)
	{
		printf("%d:", i);
		for (size_t j = 0; j < coeffs.size(); j++)
		{
			const DSL_Dmatrix &mtx = *coeffs[j];
			printf(" %g", mtx[i]);
		}
		printf("\n");
	}


	return DSL_OKAY;
}

JulianeMü
Posts: 4
Joined: Wed Jan 03, 2018 8:57 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by JulianeMü » Thu Jan 11, 2018 12:26 pm

Hello again,

because I'm using jSmile, I'm trying to translate your C++ code to java. However, there is no such class like DSL_sensitivity or sensitivity in general in your jSmile. Do you may also have an idea how to make the Sensitivity Analysis in Java?

Thanks in advance!

shooltz[BayesFusion]
Site Admin
Posts: 1247
Joined: Mon Nov 26, 2007 5:51 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by shooltz[BayesFusion] » Thu Jan 11, 2018 1:17 pm

As I wrote on January 4th in the post #2 in this thread, sensitivity is only available from C++.

JulianeMü
Posts: 4
Joined: Wed Jan 03, 2018 8:57 pm

Re: Strength of Influence and Sensitivity Analysis in jSmile

Post by JulianeMü » Thu Jan 11, 2018 2:26 pm

Ok, thank you!

However, that's too bad :( I really need this function or a method to calculate the importance of each node for the target node...
If you have any idea, please let me know!

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