Dear All,
I try to use rtrend to remove the linear trend. It seems not to work well properly. Is there something wrong with my version 101.6a?
Many thanks.
--
Kind regards,
Weijia
I try to use rtrend to remove the linear trend. It seems not to work well properly. Is there something wrong with my version 101.6a?
Many thanks.
--
Kind regards,
Weijia
Attachments
-
Weijia,
Your file in not “synchronized”, so rtf seems not work here, try:
r AU.FORT.01994
and it works.
synch
mean
rtf
HTH,
Milton
On Dec 21, 2015, at 23:46, Weijia <swj<at>mail.iggcas.ac.cn> wrote:
Dear All,
I try to use rtrend to remove the linear trend. It seems not to work well properly. Is there something wrong with my version 101.6a?
Many thanks.
--
Kind regards,
Weijia
<AU.FORT.01994>
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Attachments
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Weijia,
Milton is mostly correct. The file you sent has a large initial time value.
During the computation of the slope and intercept in scm/lifite.c, the values of sum(x) and sum(x^2) lose precision due to the large values thus resulting in a negative variance making for a bad result. The variance should not be negative.
This is simply fixed by using a smaller b value. This is what synchronize command will do for you.
or
A different fix would be to make sure the summations in scm/lifite.c do not lose precision for large values. The computation of the data mean has also had this issue. I will add these fixes into the next version.
Cheers,
Brian
On Dec 21, 2015, at 11:09 PM, Milton Plasencia <mplasencia<at>inogs.it> wrote:
Weijia,
Your file in not “synchronized”, so rtf seems not work here, try:
r AU.FORT.01994
and it works.
synch
mean
rtf
HTH,
Milton
<Screen Shot 2015-12-22 at 05.07.41.png>
On Dec 21, 2015, at 23:46, Weijia <swj<at>mail.iggcas.ac.cn> wrote:
----------------------
Dear All,
I try to use rtrend to remove the linear trend. It seems not to work well properly. Is there something wrong with my version 101.6a?
Many thanks.
--
Kind regards,
Weijia
<AU.FORT.01994>
----------------------
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)
Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)
Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
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Dear Milton and Brian,
Thanks very much for your answer. This may be common while cutting continuous waveforms into a fixed length.
Merry Christmas and Happy new year 2016.
--
Kind regards,
Weijia
At 2015-12-22 21:17:24, "savage<at>uri.edu" <savage<at>uri.edu> wrote:
Weijia,
Milton is mostly correct. The file you sent has a large initial time value.
During the computation of the slope and intercept in scm/lifite.c, the values of sum(x) and sum(x^2) lose precision due to the large values thus resulting in a negative variance making for a bad result. The variance should not be negative.
This is simply fixed by using a smaller b value. This is what synchronize command will do for you.
or
A different fix would be to make sure the summations in scm/lifite.c do not lose precision for large values. The computation of the data mean has also had this issue. I will add these fixes into the next version.
Cheers,
Brian
On Dec 21, 2015, at 11:09 PM, Milton Plasencia <mplasencia<at>inogs.it> wrote:
Weijia,
Your file in not “synchronized”, so rtf seems not work here, try:
r AU.FORT.01994
and it works.
synch
mean
rtf
HTH,
Milton
<Screen Shot 2015-12-22 at 05.07.41.png>
On Dec 21, 2015, at 23:46, Weijia <swj<at>mail.iggcas.ac.cn> wrote:
Dear All,
I try to use rtrend to remove the linear trend. It seems not to work well properly. Is there something wrong with my version 101.6a?
Many thanks.
--
Kind regards,
Weijia
<AU.FORT.01994>
----------------------
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)
Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
----------------------
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)
Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
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