def propose_dream(currentVectors, history, dimensions, nChains, DEpairs, gamma,
jitter, eps):
"""
generates and returns proposal vectors given the current states
"""
sampleRange = history.ncombined_history
currentIndex = arange(sampleRange - nChains, sampleRange)[:, newaxis]
combined_history = history.combined_history
#choose some chains without replacement to combine
chains = random_no_replace(DEpairs * 2, sampleRange - 1, nChains)
# makes sure we have already selected the current chain so it is not replaced
# this ensures that the the two chosen chains cannot be the same as the chain for which the jump is
chains += (chains >= currentIndex)
chainDifferences = (
sum(combined_history[chains[:, 0:DEpairs], :], axis=1) -
sum(combined_history[chains[:, DEpairs:(DEpairs * 2)], :], axis=1))
e = random.normal(0, jitter, (nChains, dimensions))
E = random.normal(
0, eps, (nChains, dimensions)) # could replace eps with 1e-6 here
proposalVectors = currentVectors + (
1 + e) * gamma[:, newaxis] * chainDifferences + E
return proposalVectors
def propose_dream( currentVectors, history, dimensions, nChains, DEpairs, gamma, jitter, eps ):
"""
generates and returns proposal vectors given the current states
"""
sampleRange = history.ncombined_history
currentIndex = arange(sampleRange - nChains,sampleRange)[:, newaxis]
combined_history = history.combined_history
#choose some chains without replacement to combine
chains = random_no_replace(DEpairs * 2, sampleRange - 1, nChains)
# makes sure we have already selected the current chain so it is not replaced
# this ensures that the the two chosen chains cannot be the same as the chain for which the jump is
chains += (chains >= currentIndex)
chainDifferences = (sum(combined_history[chains[:, 0:DEpairs], :], axis = 1) -
sum(combined_history[chains[:, DEpairs:(DEpairs*2)], :], axis = 1))
e = random.normal(0, jitter, (nChains,dimensions))
E = random.normal(0, eps,(nChains,dimensions)) # could replace eps with 1e-6 here
proposalVectors = currentVectors + (1 + e) * gamma[:,newaxis] * chainDifferences + E
return proposalVectors
def propose_dream2(currentVectors, history, dimensions, nChains, DEpairs,
gamma, jitter, eps):
"""
generates and returns proposal vectors given the current states
"""
sampleRange = history.ncombined_history
currentIndex = arange(sampleRange - nChains, sampleRange)[:, newaxis]
combined_history = history.combined_history
#choose some chains without replacement to combine
chains = random_no_replace(1, sampleRange - 1, nChains)
# makes sure we have already selected the current chain so it is not replaced
# this ensures that the the two chosen chains cannot be the same as the chain for which the jump is
chains += (chains >= currentIndex)
proposalVectors = combined_history[chains[:, 0], :]
return proposalVectors
def propose_dream2( currentVectors, history, dimensions, nChains, DEpairs, gamma, jitter, eps ):
"""
generates and returns proposal vectors given the current states
"""
sampleRange = history.ncombined_history
currentIndex = arange(sampleRange - nChains,sampleRange)[:, newaxis]
combined_history = history.combined_history
#choose some chains without replacement to combine
chains = random_no_replace(1, sampleRange - 1, nChains)
# makes sure we have already selected the current chain so it is not replaced
# this ensures that the the two chosen chains cannot be the same as the chain for which the jump is
chains += (chains >= currentIndex)
proposalVectors = combined_history[chains[:, 0], :]
return proposalVectors
