Let's all try to summarize changes to the wiki as we would changes to the code - without that it's tough to tell what the changes are.
In this particular case, I'm not sure if all of the formatting changes were deliberate or accidental. If accidental, I wonder if the cause was a bug in GUI mode, or a bug in your browser? -Yonik http://www.lucidimagination.com On Sat, Nov 14, 2009 at 9:05 AM, Apache Wiki <wikidi...@apache.org> wrote: > Dear Wiki user, > > You have subscribed to a wiki page or wiki category on "Solr Wiki" for change > notification. > > The "FunctionQuery" page has been changed by GrantIngersoll. > http://wiki.apache.org/solr/FunctionQuery?action=diff&rev1=29&rev2=30 > > -------------------------------------------------- > > - FunctionQuery allows one to use the actual value of a numeric field and > functions of those fields in a relevancy score. > + FunctionQuery allows one to use the actual value of a numeric field and > functions of those fields in a relevancy score. > > <<TableOfContents>> > > = Using FunctionQuery = > There are a few ways to use FunctionQuery from Solr's HTTP interface: > + > 1. Embed a FunctionQuery in a regular query expressed in SolrQuerySyntax > via the _val_ hook > 1. Use the FunctionQParserPlugin, ie: {{{q={!func}log(foo)}}} > 1. Use a parameter that has an explicit type of FunctionQuery, such as > DisMaxRequestHandler's '''bf''' (boost function) parameter. > - * NOTE: the '''bf''' parameter actually takes a list of function > queries separated by whitespace and each with an optional boost. Make sure > to eliminate any internal whitespace in single function queries when using > '''bf'''. > + * NOTE: the '''bf''' parameter actually takes a list of function queries > separated by whitespace and each with an optional boost. Make sure to > eliminate any internal whitespace in single function queries when using > '''bf'''. > - * Example: {{{q=foo&bf="ord(popularity)^0.5 > recip(rord(price),1,1000,1000)^0.3"}}} > + * Example: {{{q=foo&bf="ord(popularity)^0.5 > recip(rord(price),1,1000,1000)^0.3"}}} > > See SolrPlugins#ValueSourceParser for information on how to hook in your own > FunctionQuery. > > @@ -20, +21 @@ > > There is currently no infix parser - functions must be expressed as function > calls (e.g. sum(a,b) instead of a+b) > > = Available Functions = > - > == constant == > - <!> [[Solr1.3]] > - Floating point constants. > + <!> [[Solr1.3]] Floating point constants. > + > - Example Syntax: '''1.5''' > + . Example Syntax: '''1.5''' > - > - SolrQuerySyntax Example: '''_val_:1.5''' > + SolrQuerySyntax Example: '''_val_:1.5''' > > == fieldvalue == > This function returns the numeric field value of an indexed field with a > maximum of one value per document (not multiValued). The syntax is simply > the field name by itself. 0 is returned for documents without a value in the > field. > + > - Example Syntax: '''myFloatField''' > + . Example Syntax: '''myFloatField''' > - > - SolrQuerySyntax Example: '''_val_:myFloatField''' > + SolrQuerySyntax Example: '''_val_:myFloatField''' > > == ord == > ord(myfield) returns the ordinal of the indexed field value within the > indexed list of terms for that field in lucene index order (lexicographically > ordered by unicode value), starting at 1. In other words, for a given field, > all values are ordered lexicographically; this function then returns the > offset of a particular value in that ordering. The field must have a maximum > of one value per document (not multiValued). 0 is returned for documents > without a value in the field. > + > - Example: If there were only three values for a particular field: > "apple","banana","pear", then ord("apple")=1, ord("banana")=2, ord("pear")=3 > + . Example: If there were only three values for a particular field: > "apple","banana","pear", then ord("apple")=1, ord("banana")=2, ord("pear")=3 > - > - Example Syntax: '''ord(myIndexedField)''' > + Example Syntax: '''ord(myIndexedField)''' > - > - Example SolrQuerySyntax: '''_val_:"ord(myIndexedField)"''' > + Example SolrQuerySyntax: '''_val_:"ord(myIndexedField)"''' > > + WARNING: as of Solr 1.4, ord() and rord() can cause excess memory use since > they must use a FieldCache entry at the top level reader, while sorting and > function queries now use entries at the segment level. Hence sorting or > using a different function query, in addition to ord()/rord() will double > memory use. > - WARNING: as of Solr 1.4, ord() and rord() can cause excess memory use since > they must use a FieldCache entry > - at the top level reader, while sorting and function queries now use entries > at the segment level. Hence sorting > - or using a different function query, in addition to ord()/rord() will > double memory use. > - > > WARNING: ord() depends on the position in an index and can thus change when > other documents are inserted or deleted, or if a !MultiSearcher is used. > > == rord == > The reverse ordering of what ord provides. > + > - Example Syntax: '''rord(myIndexedField)''' > + . Example Syntax: '''rord(myIndexedField)''' > - > - Example: '''rord(myDateField)''' is a metric for how old a document is: > the youngest document will return 1, the oldest document will return the > total number of documents. > + Example: '''rord(myDateField)''' is a metric for how old a document is: > the youngest document will return 1, the oldest document will return the > total number of documents. > > + WARNING: as of Solr 1.4, ord() and rord() can cause excess memory use since > they must use a FieldCache entry at the top level reader, while sorting and > function queries now use entries at the segment level. Hence sorting or > using a different function query, in addition to ord()/rord() will double > memory use. > - > - WARNING: as of Solr 1.4, ord() and rord() can cause excess memory use since > they must use a FieldCache entry > - at the top level reader, while sorting and function queries now use entries > at the segment level. Hence sorting > - or using a different function query, in addition to ord()/rord() will > double memory use. > > == sum == > - <!> [[Solr1.3]] > - sum(x,y,...) returns the sum of multiple functions. > + <!> [[Solr1.3]] sum(x,y,...) returns the sum of multiple functions. > + > - Example Syntax: '''sum(x,1)''' > + . Example Syntax: '''sum(x,1)''' > - > - Example Syntax: '''sum(x,y)''' > + Example Syntax: '''sum(x,y)''' > - > - Example Syntax: '''sum(sqrt(x),log(y),z,0.5)''' > + Example Syntax: '''sum(sqrt(x),log(y),z,0.5)''' > > == sub == > - <!> [[Solr1.4]] > - sub(x,y) returns x-y > + <!> [[Solr1.4]] sub(x,y) returns x-y > + > - Example: '''sub(myfield,myfield2)''' > + . Example: '''sub(myfield,myfield2)''' > - > - Example: '''sub(100,sqrt(myfield))''' > + Example: '''sub(100,sqrt(myfield))''' > > == product == > - <!> [[Solr1.3]] > - product(x,y,...) returns the product of multiple functions. > + <!> [[Solr1.3]] product(x,y,...) returns the product of multiple functions. > + > - Example Syntax: '''product(x,2)''' > + . Example Syntax: '''product(x,2)''' > - > - Example Syntax: '''product(x,y)''' > + Example Syntax: '''product(x,y)''' > > == div == > - <!> [[Solr1.3]] > - div(x,y) divides the function x by the function y. > + <!> [[Solr1.3]] div(x,y) divides the function x by the function y. > + > - Example Syntax: '''div(1,x)''' > + . Example Syntax: '''div(1,x)''' > - > - Example Syntax: '''div(sum(x,100),max(y,1))''' > + Example Syntax: '''div(sum(x,100),max(y,1))''' > > == pow == > - <!> [[Solr1.3]] > - pow(x,y) raises the base x to the power y. > + <!> [[Solr1.3]] pow(x,y) raises the base x to the power y. > + > - Example Syntax: '''pow(x,0.5)''' same as sqrt > + . Example Syntax: '''pow(x,0.5)''' same as sqrt > - > - Example Syntax: '''pow(x,log(y))''' > + Example Syntax: '''pow(x,log(y))''' > > == abs == > - <!> [[Solr1.3]] > - abs(x) returns the absolute value of a function. > + <!> [[Solr1.3]] abs(x) returns the absolute value of a function. > + > - Example Syntax: '''abs(-5)''' > + . Example Syntax: '''abs(-5)''' > - > - Example Syntax: '''abs(x)''' > + Example Syntax: '''abs(x)''' > > == log == > - <!> [[Solr1.3]] > - log(x) returns log base 10 of the function x. > + <!> [[Solr1.3]] log(x) returns log base 10 of the function x. > + > - Example Syntax: '''log(x)''' > + . Example Syntax: '''log(x)''' > - > - Example Syntax: '''log(sum(x,100))''' > + Example Syntax: '''log(sum(x,100))''' > > == sqrt == > - <!> [[Solr1.3]] > - sqrt(x) returns the square root of the function x > + <!> [[Solr1.3]] sqrt(x) returns the square root of the function x > + > - Example Syntax: '''sqrt(2)''' > + . Example Syntax: '''sqrt(2)''' > - > - Example Syntax: '''sqrt(sum(x,100))''' > + Example Syntax: '''sqrt(sum(x,100))''' > > == map == > - <!> [[Solr1.3]] > - map(x,min,max,target) maps any values of the function x that fall within > min and max inclusive to target. min,max,target are constants. It outputs > the field's value if it does not fall between min and max. > + <!> [[Solr1.3]] map(x,min,max,target) maps any values of the function x > that fall within min and max inclusive to target. min,max,target are > constants. It outputs the field's value if it does not fall between min and > max. > + > - Example Syntax 1: '''map(x,0,0,1)''' change any values of 0 to 1... > useful in handling default 0 values > + . Example Syntax 1: '''map(x,0,0,1)''' change any values of 0 to 1... > useful in handling default 0 values > - > - Example Syntax 2 <!> [[Solr1.4]]: '''map(x,0,0,1,0)''' change any > values of 0 to 1 . and if the value is not zero it can be set to the value of > the 5th argument instead of defaulting to the field's value > + Example Syntax 2 <!> [[Solr1.4]]: '''map(x,0,0,1,0)''' change any values > of 0 to 1 . and if the value is not zero it can be set to the value of the > 5th argument instead of defaulting to the field's value > - > - > - > > == scale == > - <!> [[Solr1.3]] > - scale(x,minTarget,maxTarget) scales values of the function x such that they > fall between minTarget and maxTarget inclusive. > + <!> [[Solr1.3]] scale(x,minTarget,maxTarget) scales values of the function > x such that they fall between minTarget and maxTarget inclusive. > - Example Syntax: '''scale(x,1,2)''' all values will be between 1 and 2 > inclusive. > > - NOTE: The current implementation currently traverses all of the > function values to obtain the min and max so it can pick the correct scale. > + . Example Syntax: '''scale(x,1,2)''' all values will be between 1 and 2 > inclusive. NOTE: The current implementation currently traverses all of the > function values to obtain the min and max so it can pick the correct scale. > - > - NOTE: This implementation currently cannot distinguish when documents > have been deleted or documents that have no value, and 0.0 values will be > used for these cases. This means that if values are normally all greater > than 0.0, one can still end up with 0.0 as the min value to map from. In > these cases, an appropriate map() function could be used as a workaround to > change 0.0 to a value in the real range. example: > '''scale(map(x,0,0,5),1,2)''' > + NOTE: This implementation currently cannot distinguish when documents have > been deleted or documents that have no value, and 0.0 values will be used for > these cases. This means that if values are normally all greater than 0.0, > one can still end up with 0.0 as the min value to map from. In these cases, > an appropriate map() function could be used as a workaround to change 0.0 to > a value in the real range. example: '''scale(map(x,0,0,5),1,2)''' > > == query == > - <!> [[Solr1.4]] > - query(subquery, default) returns the score for the given subquery, or the > default value for documents not matching the query. Any type of subquery is > supported through either parameter dereferencing {{{$otherparam}}} or direct > specification of the query string in the LocalParams via "v". > + <!> [[Solr1.4]] query(subquery, default) returns the score for the given > subquery, or the default value for documents not matching the query. Any > type of subquery is supported through either parameter dereferencing > {{{$otherparam}}} or direct specification of the query string in the > LocalParams via "v". > > - Example Syntax: '''q=product(popularity, query({!dismax v='solr > rocks'})''' returns the product of the popularity and the score of the dismax > query. > + . Example Syntax: '''q=product(popularity, query({!dismax v='solr > rocks'})''' returns the product of the popularity and the score of the dismax > query. > - > - Example Syntax: '''q=product(popularity, query($qq))&qq={!dismax}solr > rocks''' is equivalent to the previous query, using param dereferencing. > + Example Syntax: '''q=product(popularity, query($qq))&qq={!dismax}solr > rocks''' is equivalent to the previous query, using param dereferencing. > - > - Example Syntax: '''q=product(popularity, > query($qq,0.1))&qq={!dismax}solr rocks''' specifies a default score of 0.1 > for documents that don't match the dismax query. > + Example Syntax: '''q=product(popularity, query($qq,0.1))&qq={!dismax}solr > rocks''' specifies a default score of 0.1 for documents that don't match the > dismax query. > > == linear == > linear(x,m,c) implements m*x+c where m and c are constants and x is an > arbitrary function. This is equivalent to '''sum(product(m,x),c)''', but > slightly more efficient as it is implemented as a single function. > + > - Example Syntax: '''linear(x,2,4)''' returns 2*x+4 > + . Example Syntax: '''linear(x,2,4)''' returns 2*x+4 > > == recip == > A reciprocal function with '''recip(x,m,a,b)''' implementing a/(m*x+b). > m,a,b are constants, x is any numeric field or arbitrarily complex function. > > When a and b are equal, and x>=0, this function has a maximum value of 1 > that drops as x increases. Increasing the value of a and b together results > in a movement of the entire function to a flatter part of the curve. These > properties can make this an ideal function for boosting more recent documents > when x is rord(datefield). > + > - Example Syntax: '''recip(rord(creationDate),1,1000,1000)''' > + . Example Syntax: '''recip(rord(creationDate),1,1000,1000)''' > > - <!> [[Solr1.4]] > - In Solr 1.4 and later, best practice is to avoid ord() and rord() and > derive the boost directly from the value of the date field. > + <!> [[Solr1.4]] In Solr 1.4 and later, best practice is to avoid ord() and > rord() and derive the boost directly from the value of the date field. See > ms() for more details. > - See ms() for more details. > > == max == > max(x,c) returns the max of another function and a constant. Useful for > "bottoming out" another function at some constant. > + > - Example Syntax: '''max(myfield,0)''' > + . Example Syntax: '''max(myfield,0)''' > > == ms == > <!> [[Solr1.4]] > @@ -175, +149 @@ > > Arguments may be numerically indexed date fields such as !TrieDate (the > default in 1.4), or date math (examples in SolrQuerySyntax) based on a > constant date or '''NOW'''. > > '''ms()''' > + > - Equivalent to '''ms(NOW)''', number of milliseconds since the epoch. > + . Equivalent to '''ms(NOW)''', number of milliseconds since the epoch. > + > '''ms(a)''' > + > - Returns the number of milliseconds since the epoch that the argument > represents. > + . Returns the number of milliseconds since the epoch that the argument > represents. > - > - Example: '''ms(NOW/DAY)''' > + Example: '''ms(NOW/DAY)''' > - > - Example: '''ms(2000-01-01T00:00:00Z)''' > + Example: '''ms(2000-01-01T00:00:00Z)''' > - > - Example: '''ms(mydatefield)''' > + Example: '''ms(mydatefield)''' > + > '''ms(a,b)''' > + > - Returns the number of milliseconds that {{{b}}} occurs before {{{a}}} > (i.e. {{{a - b}}}). Note that this offers higher precision than > '''sub(a,b)''' because the arguments are not converted to floating point > numbers before subtraction. > + . Returns the number of milliseconds that {{{b}}} occurs before {{{a}}} > (i.e. {{{a - b}}}). Note that this offers higher precision than > '''sub(a,b)''' because the arguments are not converted to floating point > numbers before subtraction. > - > - Example: '''ms(NOW,mydatefield)''' > + Example: '''ms(NOW,mydatefield)''' > - > - Example: '''ms(mydatefield,2000-01-01T00:00:00Z)''' > + Example: '''ms(mydatefield,2000-01-01T00:00:00Z)''' > - > - Example: '''ms(datefield1,datefield2)''' > + Example: '''ms(datefield1,datefield2)''' > + > + == dist == > + [[Solr1.5]] > + > + Return the Distance between two Vectors (points) in an n-dimensional space. > See http://en.wikipedia.org/wiki/Lp_space for more information. Takes in > the power, plus two or more !ValueSource instances and calculates the > distances between the two vectors. Each !ValueSource must be a number. > + > + Common cases: > + > + ||<tablestyle="width: 467px; height: 88px;">Power ||Common Name || > + ||0 ||Sparseness calculation || > + ||1||Manhattan (taxicab) Distance|| > + ||2||Euclidean Distance|| > + ||Infinite||Infinite norm - maximum value in the vector|| > + > + > > === Date Boosting === > Boosting more recent content is a common use case. One way is to use a > {{{recip}}} function in conjunction with {{{ms}}}. > @@ -203, +191 @@ > > Also see > http://wiki.apache.org/solr/SolrRelevancyFAQ#How_can_I_boost_the_score_of_newer_documents > > == top == > - <!> [[Solr1.4]] > - Causes it's function query argument to derive it's values from the > top-level IndexReader containing all parts of an index. For example, the > ordinal of a value in a single segment will be different from the ordinal of > that same value in the complete index. The ord() and rord() functions > implicitly use top() and hence ord(foo) is equivalent to top(ord(foo)). > + <!> [[Solr1.4]] Causes it's function query argument to derive it's values > from the top-level IndexReader containing all parts of an index. For > example, the ordinal of a value in a single segment will be different from > the ordinal of that same value in the complete index. The ord() and rord() > functions implicitly use top() and hence ord(foo) is equivalent to > top(ord(foo)). > > = General Example = > - > - To give more idea about the use of the function query, suppose index stores > dimensions in meters '''x''', '''y''','''z''' of some hypothetical boxes with > arbitrary names stored in field '''boxname'''. > + To give more idea about the use of the function query, suppose index stores > dimensions in meters '''x''', '''y''','''z''' of some hypothetical boxes with > arbitrary names stored in field '''boxname'''. Suppose we want to search for > box matching name ''findbox'' but ranked according to volumes of boxes, the > query params would be: > - Suppose we want to search for box matching name ''findbox'' but ranked > according to volumes of boxes, the query params would be: > + > {{{ > q=boxname:findbox+_val_:"product(product(x,y),z)" > }}} > - > Although this will rank the results based on volumes but in order to get the > computed volume you will need to add parameter... > + > {{{ > &fl=*,score > }}} > - > ...where '''score''' will contain the resultant volume. > > Suppose you also have a field containing weight of the box as 'weight', then > to sort by the density of the box and return the value of the density in > score you query should be... > @@ -226, +211 @@ > > {{{ > http://localhost:8983/solr/select/?q=boxname:findbox+_val_:"div(weight,product(product(x,y),z))"&fl=boxname,x,y,z,weight,score > }}} > - > >
