A question regarding the setSlop method of class PhraseQuery (Lucene version 3.0.1)

Tarun sapra

at Jun 27, 2010 at 3:51 pm

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng wrote:

Hi,

I know the indexed content contains the following text: "This is a test".
And the search phrase I used is "This is a formal test", and then I set the
slop of the PhraseQuery as 2 with setSlop(2), but I found that I can not
get
a search result. If I set the search phrase as "This is formal test", then
I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query phrase. If
zero, then this is an exact phrase search. For larger values this works
like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to moves
of
terms in the query phrase out of position. For example, to switch the order
of two words requires two moves (the first move places the words atop one
another), so to permit re-orderings of phrases, the slop must be at least
two.

More exact matches are scored higher than sloppier matches, thus search
results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

A peng

at Jun 28, 2010 at 6:08 am

⇧

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng wrote:

Hi,

I know the indexed content contains the following text: "This is a test".
And the search phrase I used is "This is a formal test", and then I set the
slop of the PhraseQuery as 2 with setSlop(2), but I found that I can not
get
a search result. If I set the search phrase as "This is formal test", then
I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query phrase. If
zero, then this is an exact phrase search. For larger values this works
like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to moves
of
terms in the query phrase out of position. For example, to switch the order
of two words requires two moves (the first move places the words atop one
another), so to permit re-orderings of phrases, the slop must be at least
two.

More exact matches are scored higher than sloppier matches, thus search
results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

Tarun sapra

at Jun 28, 2010 at 6:43 am

⇧

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it should work
because "is" and "a" are stop words thus the words "This" and "test" are 2
slop factor apart but in your search phrase "This is a formal test" the
words "This" and "test" are 3 slop factor thats why it's nor working
now in search phrase "This is formal test" the words "This" and "test" are 2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng wrote:

Hi,

I know the indexed content contains the following text: "This is a

test".

And the search phrase I used is "This is a formal test", and then I set the
slop of the PhraseQuery as 2 with setSlop(2), but I found that I can

not

get
a search result. If I set the search phrase as "This is formal test", then
I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query phrase. If
zero, then this is an exact phrase search. For larger values this works
like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to

moves

of
terms in the query phrase out of position. For example, to switch the order
of two words requires two moves (the first move places the words atop

one

another), so to permit re-orderings of phrases, the slop must be at

least

two.

More exact matches are scored higher than sloppier matches, thus search
results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

A peng

at Jun 28, 2010 at 1:11 pm

⇧

Hi,

My test result is that whenever the search phrase contains a word that don't
exist in the document, the search result will be empty no matter how big the
slop factor I set, seems this is a bug of Lucene, or it is work as design?

2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it should
work
because "is" and "a" are stop words thus the words "This" and "test" are 2
slop factor apart but in your search phrase "This is a formal test" the
words "This" and "test" are 3 slop factor thats why it's nor working
now in search phrase "This is formal test" the words "This" and "test" are
2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng wrote:

Hi,

I know the indexed content contains the following text: "This is a

test".

And the search phrase I used is "This is a formal test", and then I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found that I can

not

get
a search result. If I set the search phrase as "This is formal test", then
I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query

phrase.

If

zero, then this is an exact phrase search. For larger values this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to

moves

of
terms in the query phrase out of position. For example, to switch the order
of two words requires two moves (the first move places the words atop

one

another), so to permit re-orderings of phrases, the slop must be at

least

two.

More exact matches are scored higher than sloppier matches, thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

Erick Erickson

at Jun 28, 2010 at 1:21 pm

⇧

I think you're misunderstanding the intent of PhraseQueries and slop. Slop
is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST exist.
So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng wrote:

Hi,

My test result is that whenever the search phrase contains a word that
don't
exist in the document, the search result will be empty no matter how big
the
slop factor I set, seems this is a bug of Lucene, or it is work as design?

2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it should
work
because "is" and "a" are stop words thus the words "This" and "test" are 2
slop factor apart but in your search phrase "This is a formal test" the
words "This" and "test" are 3 slop factor thats why it's nor working
now in search phrase "This is formal test" the words "This" and "test" are
2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text: "This is a

test".

And the search phrase I used is "This is a formal test", and then I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found that I

can

not

get
a search result. If I set the search phrase as "This is formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query

phrase.

If

zero, then this is an exact phrase search. For larger values this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to

moves

of
terms in the query phrase out of position. For example, to switch

the

order

of two words requires two moves (the first move places the words

atop

one

another), so to permit re-orderings of phrases, the slop must be at

least

two.

More exact matches are scored higher than sloppier matches, thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

Tarun sapra

at Jun 28, 2010 at 3:33 pm

⇧

Hey Erick

Thanks mate!

So I guess my explanation in the mail chain above was correct!

On Mon, Jun 28, 2010 at 6:20 AM, Erick Erickson wrote:

I think you're misunderstanding the intent of PhraseQueries and slop. Slop
is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST exist.
So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng wrote:

Hi,

My test result is that whenever the search phrase contains a word that
don't
exist in the document, the search result will be empty no matter how big
the
slop factor I set, seems this is a bug of Lucene, or it is work as design?
2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it should
work
because "is" and "a" are stop words thus the words "This" and "test"

are

2

slop factor apart but in your search phrase "This is a formal test" the
words "This" and "test" are 3 slop factor thats why it's nor working
now in search phrase "This is formal test" the words "This" and "test" are
2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text: "This is

a

test".

And the search phrase I used is "This is a formal test", and then

I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found that I

can

not

get
a search result. If I set the search phrase as "This is formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query

phrase.

If

zero, then this is an exact phrase search. For larger values this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond

to

moves

of
terms in the query phrase out of position. For example, to switch

the

order

of two words requires two moves (the first move places the words

atop

one

another), so to permit re-orderings of phrases, the slop must be

at

least

two.

More exact matches are scored higher than sloppier matches, thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

Erick Erickson

at Jun 28, 2010 at 6:56 pm

⇧

No, I don't think so. The critical bit is that the indexed text
does NOT contain the word "formal". So searching for
any phrase that DOES contain "formal" should fail no matter
what the slop.

Phrase queries are something like "find all the words in this
search string, ignoring some number of intervening tokens not in the
search string". There's nothing in there about "find only some of the
words in the search string"....

I'm guessing that the original post had a typo in the success case,
because it's contradicted by "a peng's" second post. It's always
possible that I'm experiencing a brain short......

Best
Erick

On Mon, Jun 28, 2010 at 11:32 AM, tarun sapra wrote:

Hey Erick

Thanks mate!

So I guess my explanation in the mail chain above was correct!

On Mon, Jun 28, 2010 at 6:20 AM, Erick Erickson <erickerickson@gmail.com

wrote:
I think you're misunderstanding the intent of PhraseQueries and slop. Slop
is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST exist.
So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng wrote:

Hi,

My test result is that whenever the search phrase contains a word that
don't
exist in the document, the search result will be empty no matter how

big

the
slop factor I set, seems this is a bug of Lucene, or it is work as design?
2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it

should

work
because "is" and "a" are stop words thus the words "This" and "test"

are

2

slop factor apart but in your search phrase "This is a formal test"

the

words "This" and "test" are 3 slop factor thats why it's nor working
now in search phrase "This is formal test" the words "This" and

"test"

are

2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text: "This

is

a

test".

And the search phrase I used is "This is a formal test", and

then

I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found that

I

can

not

get
a search result. If I set the search phrase as "This is formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in query

phrase.

If

zero, then this is an exact phrase search. For larger values

this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units

correspond

to

moves

of
terms in the query phrase out of position. For example, to

switch

the

order

of two words requires two moves (the first move places the

words

atop

one

another), so to permit re-orderings of phrases, the slop must

be

at

least

two.

More exact matches are scored higher than sloppier matches,

thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

A peng

at Jun 29, 2010 at 1:58 am

⇧

Hi Erick,

Thanks for you reply, now I get the point why I can not get the search
result. But can you guide me how can I use Lucene to implement the following
search feature:
Basically we can call this feature "fuzzy phrase search", which means the
search phrase may contains more words or less words compared to the
sentences indexed in the document. Again I want to use the sample I posted
to demo it:

The document contains a sentence "This is a test", and the search phrase is
"This is a formal test", as there is only one word difference between the
two sentences, how can I get the "This is a test" phrase as the search
result?

Thanks.

2010/6/29 Erick Erickson <erickerickson@gmail.com>

No, I don't think so. The critical bit is that the indexed text
does NOT contain the word "formal". So searching for
any phrase that DOES contain "formal" should fail no matter
what the slop.

Phrase queries are something like "find all the words in this
search string, ignoring some number of intervening tokens not in the
search string". There's nothing in there about "find only some of the
words in the search string"....

I'm guessing that the original post had a typo in the success case,
because it's contradicted by "a peng's" second post. It's always
possible that I'm experiencing a brain short......

Best
Erick

On Mon, Jun 28, 2010 at 11:32 AM, tarun sapra wrote:

Hey Erick

Thanks mate!

So I guess my explanation in the mail chain above was correct!

On Mon, Jun 28, 2010 at 6:20 AM, Erick Erickson <erickerickson@gmail.com

wrote:
I think you're misunderstanding the intent of PhraseQueries and slop. Slop
is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST

exist.

So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng wrote:

Hi,

My test result is that whenever the search phrase contains a word

that

don't
exist in the document, the search result will be empty no matter how

big

the
slop factor I set, seems this is a bug of Lucene, or it is work as design?
2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it

should

work
because "is" and "a" are stop words thus the words "This" and

"test"

are

2

slop factor apart but in your search phrase "This is a formal test"

the

words "This" and "test" are 3 slop factor thats why it's nor

working

now in search phrase "This is formal test" the words "This" and

"test"

are

2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <

zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text: "This

is

a

test".

And the search phrase I used is "This is a formal test", and

then

I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found

that

I

can

not

get
a search result. If I set the search phrase as "This is

formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in

query

phrase.

If

zero, then this is an exact phrase search. For larger values

this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units

correspond

to

moves

of
terms in the query phrase out of position. For example, to

switch

the

order

of two words requires two moves (the first move places the

words

atop

one

another), so to permit re-orderings of phrases, the slop must

be

at

least

two.

More exact matches are scored higher than sloppier matches,

thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

A peng

at Jun 30, 2010 at 12:31 am

⇧

Hi Erick,

Any comments about this requirement?

2010/6/29 a peng <zhoudengpeng@gmail.com>

Hi Erick,

Thanks for you reply, now I get the point why I can not get the search
result. But can you guide me how can I use Lucene to implement the following
search feature:
Basically we can call this feature "fuzzy phrase search", which means the
search phrase may contains more words or less words compared to the
sentences indexed in the document. Again I want to use the sample I posted
to demo it:

The document contains a sentence "This is a test", and the search phrase is
"This is a formal test", as there is only one word difference between the
two sentences, how can I get the "This is a test" phrase as the search
result?

Thanks.

2010/6/29 Erick Erickson <erickerickson@gmail.com>

No, I don't think so. The critical bit is that the indexed text

does NOT contain the word "formal". So searching for
any phrase that DOES contain "formal" should fail no matter
what the slop.

Phrase queries are something like "find all the words in this
search string, ignoring some number of intervening tokens not in the
search string". There's nothing in there about "find only some of the
words in the search string"....

I'm guessing that the original post had a typo in the success case,
because it's contradicted by "a peng's" second post. It's always
possible that I'm experiencing a brain short......

Best
Erick

On Mon, Jun 28, 2010 at 11:32 AM, tarun sapra <t.sapra97@gmail.com>
wrote:

Hey Erick

Thanks mate!

So I guess my explanation in the mail chain above was correct!

On Mon, Jun 28, 2010 at 6:20 AM, Erick Erickson <

erickerickson@gmail.com

wrote:
I think you're misunderstanding the intent of PhraseQueries and slop. Slop
is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST

exist.

So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

My test result is that whenever the search phrase contains a word

that

don't
exist in the document, the search result will be empty no matter how

big

the
slop factor I set, seems this is a bug of Lucene, or it is work as design?
2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it

should

work
because "is" and "a" are stop words thus the words "This" and

"test"

are

2

slop factor apart but in your search phrase "This is a formal

test"

the

words "This" and "test" are 3 slop factor thats why it's nor

working

now in search phrase "This is formal test" the words "This" and

"test"

are

2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <

zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text:

"This

is

a

test".

And the search phrase I used is "This is a formal test", and

then

I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found

that

I

can

not

get
a search result. If I set the search phrase as "This is

formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in

query

phrase.

If

zero, then this is an exact phrase search. For larger values

this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units

correspond

to

moves

of
terms in the query phrase out of position. For example, to

switch

the

order

of two words requires two moves (the first move places the

words

atop

one

another), so to permit re-orderings of phrases, the slop

must

be

at

least

two.

More exact matches are scored higher than sloppier matches,

thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

reply | permalink

Erick Erickson

at Jun 30, 2010 at 1:09 am

⇧

No, I really don't have a good solution off the top of my head, perhaps
others can chime in...

Although I suppose you could fire multiple queries dropping out
some number of search terms, but I don't know whether that
satisfies your requirements. E.g. search the following phrases
"this is a formal test"
"this is a formal"
"this is a test"
"this is formal test"
"this a formal test"
"is a formal test"

and so on...

Best
Erick

On Tue, Jun 29, 2010 at 8:30 PM, a peng wrote:

Hi Erick,

Any comments about this requirement?

2010/6/29 a peng <zhoudengpeng@gmail.com>

Hi Erick,

Thanks for you reply, now I get the point why I can not get the search
result. But can you guide me how can I use Lucene to implement the following
search feature:
Basically we can call this feature "fuzzy phrase search", which means the
search phrase may contains more words or less words compared to the
sentences indexed in the document. Again I want to use the sample I posted
to demo it:

The document contains a sentence "This is a test", and the search phrase is
"This is a formal test", as there is only one word difference between the
two sentences, how can I get the "This is a test" phrase as the search
result?

Thanks.

2010/6/29 Erick Erickson <erickerickson@gmail.com>

No, I don't think so. The critical bit is that the indexed text

does NOT contain the word "formal". So searching for
any phrase that DOES contain "formal" should fail no matter
what the slop.

Phrase queries are something like "find all the words in this
search string, ignoring some number of intervening tokens not in the
search string". There's nothing in there about "find only some of the
words in the search string"....

I'm guessing that the original post had a typo in the success case,
because it's contradicted by "a peng's" second post. It's always
possible that I'm experiencing a brain short......

Best
Erick

On Mon, Jun 28, 2010 at 11:32 AM, tarun sapra <t.sapra97@gmail.com>
wrote:

Hey Erick

Thanks mate!

So I guess my explanation in the mail chain above was correct!

On Mon, Jun 28, 2010 at 6:20 AM, Erick Erickson <

erickerickson@gmail.com

wrote:
I think you're misunderstanding the intent of PhraseQueries and

slop.

Slop

is the number of intervening tokens that may exist between the words
you're looking for. However, all the words you're looking for MUST

exist.

So,

<<< whenever the search phrase contains a word that don't
exist in the document, the search result will be empty >>>

is exactly how this is intended to work.

HTH
Erick

On Mon, Jun 28, 2010 at 9:09 AM, a peng <zhoudengpeng@gmail.com>

wrote:

Hi,

My test result is that whenever the search phrase contains a word

that

don't
exist in the document, the search result will be empty no matter

how

big

the
slop factor I set, seems this is a bug of Lucene, or it is work as design?
2010/6/28 tarun sapra <t.sapra97@gmail.com>

Hi ,

I think I have been able to understand whats happening here...

Indexed Content : "This is a test".
your search phrase : "This is a formal test"
your setting the slop factor 2 , now if your slop factor is 3 it

should

work
because "is" and "a" are stop words thus the words "This" and

"test"

are

2

slop factor apart but in your search phrase "This is a formal

test"

the

words "This" and "test" are 3 slop factor thats why it's nor

working

now in search phrase "This is formal test" the words "This" and

"test"

are

2
slop factor apart thats why this phrase is working.

On Mon, Jun 28, 2010 at 11:37 AM, a peng <

zhoudengpeng@gmail.com>

wrote:

Hi,

I am using StandardAnalyzer(Version.LUCENE_30);

2010/6/27 tarun sapra <t.sapra97@gmail.com>

which analyzer are you usin'?

On Sun, Jun 27, 2010 at 7:12 AM, a peng <

zhoudengpeng@gmail.com>

wrote:

Hi,

I know the indexed content contains the following text:

"This

is

a

test".

And the search phrase I used is "This is a formal test",

and

then

I

set

the

slop of the PhraseQuery as 2 with setSlop(2), but I found

that

I

can

not

get
a search result. If I set the search phrase as "This is

formal

test",

then

I
can get the search result.

So what is the problem here, thanks in advance.

Attached is the Java doc for the setSlop method:

public void *setSlop*(int s)

Sets the number of other words permitted between words in

query

phrase.

If

zero, then this is an exact phrase search. For larger

values

this

works

like
a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units

correspond

to

moves

of
terms in the query phrase out of position. For example, to

switch

the

order

of two words requires two moves (the first move places the

words

atop

one

another), so to permit re-orderings of phrases, the slop

must

be

at

least

two.

More exact matches are scored higher than sloppier

matches,

thus

search

results are sorted by exactness.

The slop is zero by default, requiring exact matches.

--
Thanks & Regards
Tarun Sapra

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A question regarding the setSlop method of class PhraseQuery (Lucene version 3.0.1)

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