### Statistical sampling

#### MCMC

Here are the MCMC test runs shown in the slides.

set chimode = 0

set gridflag = 0

set shrcoords = 1

setlens 1 1

alpha 1 0 0 0.2 0.3 0 0 0 0 1

1 0 0 1 0 0 0 0 0 0

stepsize 1

0.3 0 0 0.3 0.3 0 0 0 0 0

0 0 0 0 0 0 0 0

set seed = -22

chitest on 1

0.3 0.05

set seed = -24

# mcmc1a: simple Gaussian steps

MCMCset 1 Nchain 10 spread 3

MCMCrun mcmc1a

# mcmc1b: adaptive Gaussian steps

MCMCset 2 Nchain 10 spread 3

MCMCrun mcmc1b

stepsize 1

0.001 0 0 0.001 0.3 0 0 0 0 0

0 0 0 0 0 0 0 0

# mcmc1d: simple; start with tiny steps, adjust scale

MCMCset 1 Nchain 10 spread 1000

MCMCrun mcmc1d

quit

And here is an example of an MCMC run for the test case discussed on the
fitting page.

set omega = 0.27

set lambda = 0.73

set hvale = 1.0e4

set zlens = 0.3

set zsrc = 2.0

set gridflag = 0

set chimode = 0

set checkparity = 0

set omitcore = 1.0e-6

data testquad.dat

setlens fit2c.start

MCMCset 2 Nchain 10

MCMCrun fit4

quit