function?laguerre_rule?（?order?a?b?filename?）

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%?可直接在函數(shù)名前設(shè)置輸出為??[xw]=??其中x為積分點(diǎn)，w為權(quán)重，此處為求積分，因此w之和可能不為1。
%%?LAGUERRE_RULE?generates?a?Gauss-Laguerre?rule.
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%??Discussion:
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%????This?program?computes?a?standard?or?exponentially?weighted?
%????Gauss-Laguerre?quadrature?rule?and?writes?it?to?a?file.
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%????The?user?specifies:
%????*?the?ORDER?（number?of?points）?in?the?rule;
%????*?A?the?left?endpoint;
%????*?B?the?scale?factor?in?the?exponential;
%????*?FILENAME?the?root?name?of?the?output?files.
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%??Licensing:
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%????This?code?is?distributed?under?the?GNU?LGPL?license.
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%??Modified:
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%????10?February?2014
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%??Author:
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%????John?Burkardt
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??timestamp?（?）;
??fprintf?（?1?‘\n‘?）;
??fprintf?（?1?‘LAGUERRE_RULE\n‘?）;
??fprintf?（?1?‘??MATLAB?version\n‘?）;
??fprintf?（?1?‘\n‘?）;
??fprintf?（?1?‘??Compute?a?Gauss-Laguerre?rule?for?approximating\n‘?）;
??fprintf?（?1?‘????Integral?（?a?<=?x???fprintf?（?1?‘??of?order?ORDER.\n‘?）;
??fprintf?（?1?‘\n‘?）;
??fprintf?（?1?‘??The?user?specifies?ORDER?A?B?and?FILENAME.\n‘?）;
??fprintf?（?1?‘\n‘?）;
??fprintf?（?1?‘??ORDER?is?the?number?of?points.\n‘?）;
??fprintf?（?1?‘??A?is?the?left?endpoint?（typically?0）.\n‘?）;
??fprintf?（?1?‘??B?is?the?exponential?scale?factor?（typically?1）.\n‘?）;
??fprintf?（?1?‘??FILENAME?is?used?to?generate?3?files:\n‘?）;
??fprintf?（?1?‘??*?filename_w.txt?-?the?weight?file\n‘?）;
??fprintf?（?1?‘??*?filename_x.txt?-?the?abscissa?file.\n‘?）;
??fprintf?（?1?‘??*?filename_r.txt?-?the?region?file.\n‘?）;
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%??Initialize?the?parameters.
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??alpha?=?0.0;
??beta?=?0.0;
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%??Get?ORDER.
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??if?（?nargin?????order?=?input?（?‘??Enter?the?rule?order?ORDER:??‘?）;
??elseif?（?ischar?（?order?）?）
????order?=?str2num?（?order?）;
??end
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%??Get?A.
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??if?（?nargin?????fprintf?（?1?‘\n‘?）;
????fprintf?（?1?‘??A?is?the?left?endpoint?typically?0.\n‘?）;
????fprintf?（?1?‘\n‘?）;
????a?=?input?（?‘??Enter?the?value?of?A.‘?）;
??elseif?（?ischar?（?a?）?）
????a?=?str2num?（?a?）;
??end
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%??Get?B.
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??if?（?nargin?????fprintf?（?1?‘\n‘?）;
????fprintf?（?1?‘??B?is?the?exponential?scale?factor?typically?1.\n‘?）;
????fprintf?（?1?‘\n‘?）;
????b?=?input?（?‘??Enter?the?value?of?B.‘?）;
??elseif?（?ischar?（?b?）?）
????b?=?str2num?（?b?）;
??end
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%??Get?the?quadrature?file?root?name:
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??if?（?nargin?????fprintf?（?1?‘\n‘?）;
????fprintf?（?1?‘??FILENAME?specifies??the?‘‘root?name‘‘?of?a?set?of?quadrature?files）.\n‘?）;
????filename?=?input?（?‘??Enter?the?value?of?FILENAME?as?a?quoted?string:??‘?）;
??end
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%??Input?summary.
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??fprintf?（?1?‘\n‘?）;
??fprintf?（?1?‘??ORDER?=?%d\n‘?order?）;
??fprintf?（?1?‘??A?=?%f\n‘?a）;
??fprintf?（?1?‘??B?=?%f\n‘?b?）;
??fprintf?（?1?‘??FILENAME?=?“%s“.\n‘?filename?）;
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%??Construct?the?rule.
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??kind?=?5;
??[?x?w?]?=?cgqf?（?order?kind?alpha?beta