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1月4日留美经济学会（CES）招待会暨国内高校宣讲会

1月4日留美经济学会（CES）招待会暨国内高校宣讲会# Economics - 经济

l*r2009-01-03 08:01

1 楼

I wrote Fortran program to calculate the average and standard deviations of
a large number of data. It turned out that the instantaneous results are
always positive, then the last several sets of average values became
negative. I think it is because the total sum of those data reached the
limit of computer. So it began to show negative results.
I define the type of data as double precision. Is there anyone knows how to
solve the problem? Thanks a lot.

c*t2009-01-03 08:01

2 楼

烦请版主置顶，谢谢。
1月4日晚6点至8点，在Yerba Beuna Salon 12-14 (level B2), S.F. Marriott
Hotel, 中国留美经济学会(CES)举行招待会，欢迎大家参加。Reception后，可以一起
去吃晚餐。
与会的有国内高校经管院系的学术带头人，与大家分享信息。
由于大会组织方的疏忽，Reception的信息没有出现在ASSA会议手册中。请大家转
告感兴趣的朋友。
下面是CES president Dr. Holly Wang的通知：
Chinese Economists Society (CES) is hosting a business meeting and reception
at ASSA conference on January 4, 2009, 6pm, Yerba Beuna Salon 12-14 (Level
B2), San Francisco Marriott Hotel (at the cross of Mission and Fourth Street
).
Many uni

f*y2009-01-03 08:01

3 楼

scale一下 if 精度不是啥concern

of
to

【在 l********r 的大作中提到】

: I wrote Fortran program to calculate the average and standard deviations of
: a large number of data. It turned out that the instantaneous results are
: always positive, then the last several sets of average values became
: negative. I think it is because the total sum of those data reached the
: limit of computer. So it began to show negative results.
: I define the type of data as double precision. Is there anyone knows how to
: solve the problem? Thanks a lot.

g*y2009-01-03 08:01

4 楼

Must go! Lots of fun! Strongly recommened!!! hehe

l*82009-01-03 08:01

5 楼

I bet it is not the fault of "double precision" data. The "double precision"
data are floating point. Their range is extremely wide (IEEE double can be
up to 1e307) and it is not possible to overflow from positive to negative (
you will only get a +NaN).
I think you're seeing negative numbers because the "count" is an integer and
FORTRAN calculates the average as (double)"sum" / (int)"count". If you have
more than 2 billion data entries (or 4 billion if the "count" is unsigned),
you'll see negat

q*l2009-01-03 08:01

6 楼

Dr. Yulu Chen (Nankai University)?????

reception
Level

【在 c*******t 的大作中提到】

: 烦请版主置顶，谢谢。
: 1月4日晚6点至8点，在Yerba Beuna Salon 12-14 (level B2), S.F. Marriott
: Hotel, 中国留美经济学会(CES)举行招待会，欢迎大家参加。Reception后，可以一起
: 去吃晚餐。
: 与会的有国内高校经管院系的学术带头人，与大家分享信息。
: 由于大会组织方的疏忽，Reception的信息没有出现在ASSA会议手册中。请大家转
: 告感兴趣的朋友。
: 下面是CES president Dr. Holly Wang的通知：
: Chinese Economists Society (CES) is hosting a business meeting and reception
: at ASSA conference on January 4, 2009, 6pm, Yerba Beuna Salon 12-14 (Level