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author | shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2003-07-28 02:56:43 +0000 |
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committer | shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2003-07-28 02:56:43 +0000 |
commit | 4cbf09d1fe858f39bd091a6cbe59dcc56ce463aa (patch) | |
tree | 3e58bf6e621cda921eea09a01a71c40e628017ae /ext/bigdecimal/bigdecimal_en.html | |
parent | b388591ab76c81eb2c7b4a5d66a840235f1365df (diff) | |
download | ruby-4cbf09d1fe858f39bd091a6cbe59dcc56ce463aa.tar.gz |
Bug fix from Javier Goizueta.
ROUND_MODE & round changed(source & docs).
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4187 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext/bigdecimal/bigdecimal_en.html')
-rw-r--r-- | ext/bigdecimal/bigdecimal_en.html | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/ext/bigdecimal/bigdecimal_en.html b/ext/bigdecimal/bigdecimal_en.html index ed192fca58..2d86adcc6b 100644 --- a/ext/bigdecimal/bigdecimal_en.html +++ b/ext/bigdecimal/bigdecimal_en.html @@ -156,18 +156,22 @@ Suppose the return value of the mode method is f,then <B>[ROUND error control]</B><P> Rounding operation can be controlled as: <BLOCKQUOTE> -f = BigDecimal::mode(BigDecimal::COMP_MODE,flag) +f = BigDecimal::mode(BigDecimal::ROUND_MODE,flag) </BLOCKQUOTE> where flag must be one of: <TABLE> -<TR><TD>COMP_MODE_TRUNCATE</TD><TD>truncate</TD></TR> -<TR><TD>COMP_MODE_ROUND</TD><TD>round,default</TD></TR> -<TR><TD>COMP_MODE_CEIL</TD><TD>ceil</TD></TR> -<TR><TD>COMP_MODE_FLOOR</TD><TD>floor</TD></TR> -<TR><TD>COMP_MODE_EVEN</TD><TD>Banker's rounding</TD></TR> + +<TR><TD>ROUND_UP</TD><TD>round away from zero.</TD></TR> +<TR><TD>ROUND_DOWN</TD><TD>round towards zero(truncate).</TD></TR> +<TR><TD>ROUND_HALF_UP</TD><TD>round up if the digit >= 5 otherwise truncated(default).</TD></TR> +<TR><TD>ROUND_HALF_DOWN</TD><TD>round up if the digit >= 6 otherwise truncated.</TD></TR> +<TR><TD>ROUND_HALF_EVEN</TD><TD>round towards the even neighbor(Banker's rounding). +<TR><TD>ROUND_CEILING</TD><TD>round towards positive infinity(ceil).</TD></TR> +<TR><TD>ROUND_FLOOR</TD><TD>round towards negative infinity(floor).</TD></TR> </TABLE> -nil is returned if any argument is illegal.<BR> -The digit location for rounding operation can not be specified by mode method, +New rounding mode is returned,nil is returned if any argument is not an integer. +Bad specification is ignored.<BR> +The digit location for rounding operation can not be specified by this mode method, use truncate/round/ceil/floor/add/sub/mult/div mthods for each instance instead. </BLOCKQUOTE> @@ -286,8 +290,8 @@ of the target digit can be given.<BR> If n> 0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR> If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left). <CODE><PRE> - c = BigDecimal::new("1.23456").floor(4) # ==> 1.2345 - c = BigDecimal::new("15.23456").floor(-1) # ==> 10.0 + c = BigDecimal("1.23456").floor(4) # ==> 1.2345 + c = BigDecimal("15.23456").floor(-1) # ==> 10.0 </PRE></CODE> </BLOCKQUOTE> @@ -304,37 +308,33 @@ of the target digit can be given.<BR> If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR> If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left). <CODE><PRE> - c = BigDecimal::new("1.23456").ceil(4) # ==> 1.2346 - c = BigDecimal::new("15.23456").ceil(-1) # ==> 20.0 + c = BigDecimal("1.23456").ceil(4) # ==> 1.2346 + c = BigDecimal("15.23456").ceil(-1) # ==> 20.0 </PRE></CODE> </BLOCKQUOTE> <LI><B>round[(n[,b])]</B></LI><BLOCKQUOTE> c = a.round<BR> -round a to the nearest 1D<BR> +round a to the nearest 1(default)D<BR> <CODE><PRE> c = BigDecimal("1.23456").round # ==> 1 c = BigDecimal("-1.23456").round # ==> -1 </PRE></CODE> +The rounding operation changes according to BigDecimal::mode(BigDecimal::ROUND_MODE,flag) if specified. As shown in the following example,an optional integer argument (n) specifying the position of the target digit can be given.<BR> -If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR> +If n>0,then the (n+1)th digit counted from the decimal point in fraction part is processed(resulting number of fraction part digits is less than or equal to n).<BR> If n<0,then the n-th digit counted from the decimal point in integer part is processed(at least n 0's are placed from the decimal point to left). <CODE><PRE> c = BigDecimal::new("1.23456").round(4) # ==> 1.2346 c = BigDecimal::new("15.23456").round(-1) # ==> 20.0 </PRE></CODE> -If the second optional argument b is given with the non-zero value(default is zero) then -so called Banker's rounding is performed.<BR> -Suppose the digit p is to be rounded,then:<BR> - If p<5 then p is truncated<BR> - If p>5 then p is rounded up<BR> - If p is 5 then round up operation is taken only when the left hand side digit of p is odd. +Rounding operation can be specified by setting the second optional argument b with the valid ROUND_MODE.<BR> <CODE><PRE> -c = BigDecimal::new("1.23456").round(3,1) # ==> 1.234 -c = BigDecimal::new("1.23356").round(3,1) # ==> 1.234 +c = BigDecimal::new("1.23456").round(3,BigDecimal::ROUND_HALF_EVEN) # ==> 1.234 +c = BigDecimal::new("1.23356").round(3,BigDecimal::ROUND_HALF_EVEN) # ==> 1.234 </PRE></CODE> </BLOCKQUOTE> @@ -728,11 +728,11 @@ As +,-,and * are always exact(no round operation is performed unless BigDecimal. which means more momories are required to keep computation results. But,the division such as c=1.0/3.0 will always be rounded.<BR> -<H3>2. assign,add,sub,mult,div</H3> +<H3>2. add,sub,mult,div</H3> The length of the significant digits obtained from +,-,*,/ is always defined by that of right and left side of the operator. To specify the length of the significant digits by your self, -use methos assign,add,sub,mult,div. +use methos add,sub,mult,div. <CODE><PRE> BigDecimal("2").div(3,12) # 2.0/3.0 => 0.6666666666 67E0 </PRE></CODE> |