In the study, we empirically compare the two recently proposed decoding methods, i.e. Contrastive Search (CS) and Contrastive Decoding (CD), for open-ended text generation. The automatic evaluation results suggest that, while CS performs worse than CD on the MAUVE metric, it substantially surpasses CD on the diversity and coherence metrics. More notably, extensive human evaluations across three different domains demonstrate that human annotators are universally more in favor of CS over CD with substantial margins. The contradicted results between MAUVE and human evaluations reveal that MAUVE does not accurately reflect human preferences. Therefore, we call upon the research community to develop better evaluation metrics for open-ended text generation. To ensure the reproducibility of our work, we have open-sourced all our code, evaluation results, as well as human annotations at https://github.com/yxuansu/Contrastive_Search_versus_Contrastive_Decoding.

When U.S. President Joe Biden told an exhausted nation on Aug. 31 that the last C-17 cargo plane had left Taliban-controlled Kabul, ending two decades of American military misadventure in Afghanistan, he defended the frantic, bloodstained exit with a simple statement: "I was not going to extend this forever war." And yet the war grinds on. As Biden drew the curtain on Afghanistan, the CIA was quietly expanding a secret base deep in the Sahara, from which it runs drone flights to monitor al-Qaida and Islamic State group militants in Libya, as well as extremists in Niger, Chad and Mali. The military's Africa Command resumed drone strikes against the Shabab, an al-Qaida-linked group in Somalia. The Pentagon is weighing whether to send dozens of Special Forces trainers back to Somalia to help local troops fight militants.

An American military drone strike over the weekend in southern Libya killed a top recruiter and logistics specialist for Al Qaeda's branch in northwest Africa, the Pentagon said on Wednesday, and a senior military official warned of more attacks on extremists there. The military's Africa Command said in a statement that the attack killed two militants, one of whom was identified as Musa Abu Dawud, a high-ranking official in Al Qaeda in the Islamic Maghreb, known as AQIM. Mr. Dawud trained Qaeda recruits in Libya for strike operations in the region, and provided logistics, money and weapons that enabled the group to threaten and attack American and Western interests, the military statement said. Until now, the Pentagon had focused its counterterrorism strikes in Libya -- eight since President Trump took office -- almost exclusively on Islamic State fighters and operatives farther north. Over several months in 2016, the military conducted nearly 500 airstrikes in the coastal city of Surt to destroy the Islamic State's stronghold there.

The United States military carried out its first ever drone strike against Qaeda militants in southern Libya this weekend, signaling a possibly significant expansion of the American counterterrorism campaign in the North African nation. Until now, the Pentagon had focused its counterterrorism strikes in Libya almost exclusively on Islamic State fighters and operatives farther north -- eight since President Trump took office. In 2016, the military conducted nearly 500 airstrikes in the coastal city of Surt over several months to destroy the Islamic State's stronghold there. But the attack on Saturday that the military's Africa Command said had killed two militants -- later identified by a spokeswoman as belonging to Al Qaeda's branch in northwestern Africa -- took place in the country's southwest, a notorious haven for a deadly mix of Al Qaeda and other extremist groups that also operate in the Sahel region of Niger, Chad, Mali and Algeria. "This appears to be the continuation of expanding AFRICOM activity in Libya's ungoverned areas," said Deborah K.

The Libyan National Army has been battling ISIS in the cities of Sirte and Benghazi. The U.S. military has launched airstrikes this month in Yemen, Somalia, Iraq, Syria, Afghanistan and Friday, for the first time since September, in Libya. According to a defense official, the drone strike in the desert of central Libya Friday killed "several" ISIS militants in a sign the Pentagon may be ramping up pressure on terror groups in Africa. The most recent strike comes a year after the military launched nearly 500 airstrikes against ISIS in the coastal city of Sirte, located halfway between Tripoli and Benghazi. The September strike killed 17 ISIS fighters.

SIRTE, Libya Suicide bombings against Libyan forces battling to oust Islamic State from their former North African stronghold of Sirte killed at least 12 fighters and wounded about 60 there on Thursday, a hospital spokesman said.