context-specific cpds

14
Daphne Koller Local Structure Context- Specific CPDs Probabilistic Graphical Models Representation

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Representation. Probabilistic Graphical Models. Local Structure. Context-Specific CPDs. Tree CPD. A. a 0. a 1. S. (0.8,0.2). s 0. s 1. Apply. L. (0.1,0.9). l 0. l 1. Letter. SAT. (0.9,0.1). (0.4,0.6). Job. - PowerPoint PPT Presentation

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Page 1: Context-Specific CPDs

Daphne Koller

Local Structure

Context-Specific CPDs

ProbabilisticGraphicalModels

Representation

Page 2: Context-Specific CPDs

Daphne Koller

A

S

L

(0.8,0.2)

(0.9,0.1) (0.4,0.6)

(0.1,0.9)

s1

a0 a1

s0

l1l0Letter SAT

Job

Apply

Tree CPD

Page 3: Context-Specific CPDs

Which context-specific independencies are implied by the structure of this CPD? (Mark all that apply.)

A

S

L

(0.8,0.2)

(0.9,0.1) (0.4,0.6)

(0.1,0.9)

s1

a0 a1

s0

l1l0

Page 4: Context-Specific CPDs

Daphne Koller

Letter1 Letter2

Job

Choice

Tree CPD

Cc1 c2

L2

(0.8,0.2) (0.1,0.9)

l1l0L1

(0.9,0.1) (0.3,0.7)

l1l0

Page 5: Context-Specific CPDs

Which non-context-specific independency is implied by the structure of this CPD? C

c1 c2

L

(0.8,0.2) (0.1,0.9)

l1l0L

(0.9,0.1) (0.3,0.7)

l1l0

Letter1 Letter2

Job

Choice

Page 6: Context-Specific CPDs

Daphne Koller

Cc1 c2

L

(0.8,0.2) (0.1,0.9)

l1l0L

(0.9,0.1) (0.3,0.7)

l1l0

Letter1 Letter2

Job

Choice

Page 7: Context-Specific CPDs

Daphne Koller

Multiplexer CPDZ1 ZkZ2 . . .

YA

Page 8: Context-Specific CPDs

Daphne Koller

Microsoft Troubleshooters

# of parameters: 145 to 55

Page 9: Context-Specific CPDs

Daphne Koller

END END END

Page 10: Context-Specific CPDs

Suppose q is at a local minimum of a function. What will one iteration of gradient descent do?

Leave q unchanged.

Change q in a random direction.

Move q towards the global minimum of J(q).

Decrease q.

Page 11: Context-Specific CPDs

Consider the weight update:

Which of these is a correct vectorized implementation?

Page 12: Context-Specific CPDs

Fig. A corresponds to a=0.01, Fig. B to a=0.1, Fig. C to a=1.

Fig. A corresponds to a=0.1, Fig. B to a=0.01, Fig. C to a=1.

Fig. A corresponds to a=1, Fig. B to a=0.01, Fig. C to a=0.1.

Fig. A corresponds to a=1, Fig. B to a=0.1, Fig. C to a=0.01.

Page 13: Context-Specific CPDs
Page 14: Context-Specific CPDs