Answer the question at the end by quoting:

Tristano was born in Chicago on March 19, 1919. His mother, Rose Tristano (nee Malano), was also born in Chicago. His father, Michael Joseph Tristano, was born in Italy and moved to the United States as a child. Lennie was the second of four brothers.
In Ind's view, Tristano "was always so gentle, so charming and so quietly spoken that his directness could be unnerving." This directness was noted by others, including bassist Chubby Jackson, who commented that Tristano had almost no tact and would not worry about being rude or making others feel incompetent. Some of his students described Tristano as domineering, but others indicated that this impression came from his demanding discipline in training and attitude to music.  Writer Barry Ulanov commented in 1946 that Tristano "was not content merely to feel something, [...] he had to explore ideas, to experience them, to think them through carefully, thoroughly, logically until he could fully grasp them and then hold on to them." Tristano criticized the free jazz that began in the 1960s for its lack of musical logic as well as its expression of negative emotions. "If you feel angry with somebody you hit him on the nose - not try to play angry music", he commented; "Express all that is positive. Beauty is a positive thing." He expanded on this by distinguishing emotion from feeling, and suggested that playing a particular emotion was egotistical and lacking in feeling.  Tristano also complained about the commercialization of jazz and what he perceived to be the requirement to abandon the artistic part of playing in order to earn a living from performing. Later commentators have suggested that these complaints ignored the freedom that he was given by Atlantic and blamed others for what in many cases were the outcomes of his own career decisions.

What else did he say on this matter

Express all that is positive. Beauty is a positive thing." He expanded on this by distinguishing emotion from feeling,



Answer the question at the end by quoting:

Daniel Barenboim (born 15 November 1942) is an Argentine-Israeli pianist and conductor who is a citizen of Argentina, Israel, Palestine, and Spain. He is the general music director of the Berlin State Opera, and the Staatskapelle Berlin; he previously served as Music Director of the Chicago Symphony Orchestra, the Orchestre de Paris and La Scala in Milan. Barenboim is known for his work with the West-Eastern Divan Orchestra, a Seville-based orchestra of young Arab and Israeli musicians, and as a resolute critic of the Israeli occupation of Palestinian territories. Barenboim has received many awards and prizes, including an honorary Knight Commander of the Order of the British Empire, France's Legion d'honneur both as a Commander and Grand Officier, and the German Grosses Bundesverdienstkreuz and Willy Brandt Award.
In the beginning of his career, Barenboim concentrated on music of the classical era, as well as some romantic composers. He made his first recording in 1954. Notable classical recordings include the complete cycles of Mozart, Beethoven and Schubert's piano sonatas, and Mozart's piano concertos (in the latter, taking part as both soloist and conductor). Romantic recordings include Brahms's piano concertos (with John Barbirolli), Mendelssohn's Songs Without Words, and Chopin's nocturnes. Barenboim also recorded many chamber works, especially in collaboration with his first wife, Jacqueline du Pre, the violinist Itzhak Perlman, and the violinist and violist Pinchas Zukerman. Noted performances include: the complete Mozart violin sonatas (with Perlman), Brahms's violin sonatas (live concert with Perlman, previously in the studio with Zukerman), Beethoven's and Brahms's cello sonatas (with du Pre), Beethoven's and Tchaikovsky's piano trios (with du Pre and Zukerman), and Schubert's Trout Quintet (with du Pre, Perlman, Zukerman, and Zubin Mehta).  Notable recordings as a conductor include: the complete symphonies of Beethoven, Brahms, Bruckner, Schubert and Schumann, the Da Ponte operas of Mozart, numerous operas by Wagner, including the complete Ring Cycle, and various concertos. Barenboim has written about his changing attitude to the music of Mahler; he has recorded Mahler's Fifth, Seventh and Ninth symphonies and Das Lied von der Erde. He has also performed and recorded the Concierto de Aranjuez by Rodrigo and Villa-Lobos guitar concerto with John Williams as the guitar soloist.  By the late 1990s, Barenboim had widened his concert repertoire, performing works by baroque as well as twentieth-century classical composers. Examples include: J.S. Bach's The Well-Tempered Clavier (which he has played since childhood) and Goldberg Variations, Albeniz's Iberia, and Debussy's Preludes. In addition, he turned to other musical genres, such as jazz, and the folk music of his birthplace, Argentina. He conducted the 2006 New Year's Eve concert in Buenos Aires, in which tangos were played.  Barenboim has continued to perform and record chamber music, sometimes with members of the orchestras he has led. Some examples include the Quartet for the End of Time by Messiaen with members of the Orchestre de Paris during his tenure there, Richard Strauss with members of the Chicago Symphony Orchestra, and Mozart's Clarinet Trio with members of the Berlin Staatskapelle.  To mark Barenboim's 75th birthday, Deutsche Grammophon released a box set of 39 CDs of his solo recordings, and Sony Classical issued a box set of Barenboim's orchestral recordings on 43 CDs and three DVDs in 2017, Daniel Barenboim - A Retrospective.

Did his style ever change?