Hi Everyone, I am stuck with a simple problem. Suppose I have a vector x, and I want to calculate y[i]=3Dx[i+1]-x[i], it is very easy. I just need to write y<-x[2:length(x)]-x[1:length(x)-1]. Now if I know y, and want to know the vector x defined by x[i]=3Dx[i-1]+y[i-1] for all i, how can I do this without a loop? Thanks, Geoffrey PS. Sorry if you see a duplicate message. The previous one was in a weird format that most people would not be able to read. _______________________________________________________=0A=0A=0AThe information in this email or in any file attached hereto is=0Aintended only for the personal and confidential use of the individual=0Aor entity to which it is addressed and may contain information that is=0Aproprietary and confidential. If you are not the intended recipient of=0Athis message you are hereby notified that any review, dissemination,=0Adistribution or copying of this message is strictly prohibited. This communication is for information purposes only and should not be regarded as an offer to sell or as a solicitation of an offer to buy any financial product. Email transmission cannot be guaranteed to be secure or error-free.
> x[i]=3Dx[i-1]+y[i-1] for all i, how can I do this without a loop?It looks like x <- cumsum(y) What does 3D mean?
Hi Richard, 3D is automatically generated by the mailing list software, probably because I had ] followed by =3D without a space in the original post. What I meant was to calculate x[i] =3D x[i-1] + y[i-1] For example, if X <- 1:10 Then I want the vector Y to be 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, or in other words Y[i] =3D y[i-1] + x[i]. Yes, cumsum does the trick for this. This is what I need. Thanks. Just curious, do you know how to calculate the more generic x[i] <- f( x[i-1], y[i-1] )? Thanks, Geoffrey -----Original Message----- From: Richard M. Heiberger [mailto:rmh at temple.edu] Sent: Tuesday, December 26, 2006 9:56 AM To: Geoffrey Zhu; r-help at stat.math.ethz.ch Subject: Re: [R] vectorizing an iterative process.> x[i]=3D3Dx[i-1]+y[i-1] for all i, how can I do this without a loop?It looks like x <- cumsum(y) What does 3D mean? _______________________________________________________=0A=0A=0AThe information in this email or in any file attached hereto is=0Aintended only for the personal and confidential use of the individual=0Aor entity to which it is addressed and may contain information that is=0Aproprietary and confidential. If you are not the intended recipient of=0Athis message you are hereby notified that any review, dissemination,=0Adistribution or copying of this message is strictly prohibited. This communication is for information purposes only and should not be regarded as an offer to sell or as a solicitation of an offer to buy any financial product. Email transmission cannot be guaranteed to be secure or error-free.
I meant x[i] <- x[i-1] + y[i-1] and Y[i] <- y[i-1] + x[i] below. The mailing list software just keep adding 3D's. Sorry. -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Geoffrey Zhu Sent: Tuesday, December 26, 2006 10:03 AM To: Richard M. Heiberger; r-help at stat.math.ethz.ch Subject: Re: [R] vectorizing an iterative process. Hi Richard, 3D is automatically generated by the mailing list software, probably because I had ] followed by =3D3D without a space in the original post. What I meant was to calculate x[i] =3D3D x[i-1] + y[i-1] For example, if X <- 1:10 Then I want the vector Y to be 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, or in other words Y[i] =3D3D y[i-1] + x[i]. Yes, cumsum does the trick for this. This is what I need. Thanks. Just curious, do you know how to calculate the more generic x[i] <- f( x[i-1], y[i-1] )? Thanks, Geoffrey -----Original Message----- From: Richard M. Heiberger [mailto:rmh at temple.edu] Sent: Tuesday, December 26, 2006 9:56 AM To: Geoffrey Zhu; r-help at stat.math.ethz.ch Subject: Re: [R] vectorizing an iterative process.> x[i]=3D3D3Dx[i-1]+y[i-1] for all i, how can I do this without a loop?It looks like x <- cumsum(y) What does 3D mean? _______________________________________________________=3D0A=3D =3D0A=3D =3D0A=3D The information in this email or in any file attached hereto is=3D0A=3D intended only for the personal and confidential use of the individual=3D0A=3D or entity to which it is addressed and may contain information that is=3D0A=3D proprietary and confidential. If you are not the intended recipient of=3D0A=3D this message you are hereby notified that any review, dissemination,=3D0A=3D distribution or copying of this message is strictly prohibited. This communi=3D cation is for information purposes only and should not be regarded as an off=3D er to sell or as a solicitation of an offer to buy any financial product. Em=3D ail transmission cannot be guaranteed to be secure or error-free. ______________________________________________ R-help at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. _______________________________________________________=0A=0A=0AThe information in this email or in any file attached hereto is=0Aintended only for the personal and confidential use of the individual=0Aor entity to which it is addressed and may contain information that is=0Aproprietary and confidential. If you are not the intended recipient of=0Athis message you are hereby notified that any review, dissemination,=0Adistribution or copying of this message is strictly prohibited. This communication is for information purposes only and should not be regarded as an offer to sell or as a solicitation of an offer to buy any financial product. Email transmission cannot be guaranteed to be secure or error-free.
Yes, this solves my problem. Thanks for your help.
-----Original Message-----
From: Christos Hatzis [mailto:christos at nuverabio.com]
Sent: Tuesday, December 26, 2006 10:58 AM
To: Geoffrey Zhu; r-help at stat.math.ethz.ch
Subject: RE: [R] vectorizing an iterative process.
In your case, the recurrence relationship for x can be solved easily:
Notice that
sum{i=3D1,n}(x[i]-x[i-1]) =3D x[n] - x[0]
and therefore
x[n] =3D x[0] + sum{i=3D1,n}(y[i-1] for n=3D1, N, with the appropriate initial
condition for i=3D0, (x[0],y[0]).
Thus cumsum on y will give you a direct answer.
-Christos
Christos Hatzis, Ph.D.
Nuvera Biosciences, Inc.
400 West Cummings Park
Suite 5350
Woburn, MA 01801
Tel: 781-938-3830
www.nuverabio.com
-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Geoffrey Zhu
Sent: Tuesday, December 26, 2006 11:06 AM
To: r-help at stat.math.ethz.ch
Subject: Re: [R] vectorizing an iterative process.
I meant x[i] <- x[i-1] + y[i-1] and Y[i] <- y[i-1] + x[i] below.
The mailing list software just keep adding 3D's. Sorry.
-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Geoffrey Zhu
Sent: Tuesday, December 26, 2006 10:03 AM
To: Richard M. Heiberger; r-help at stat.math.ethz.ch
Subject: Re: [R] vectorizing an iterative process.
Hi Richard,
3D is automatically generated by the mailing list software, probably
because I had ] followed by =3D3D3D without a space in the original post.
What I meant was to calculate x[i] =3D3D3D x[i-1] + y[i-1]
For example, if X <- 1:10
Then I want the vector Y to be 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, or
in other words Y[i] =3D3D3D y[i-1] + x[i].
Yes, cumsum does the trick for this. This is what I need. Thanks.
Just curious, do you know how to calculate the more generic x[i] <- f(
x[i-1], y[i-1] )?
Thanks,
Geoffrey
-----Original Message-----
From: Richard M. Heiberger [mailto:rmh at temple.edu]
Sent: Tuesday, December 26, 2006 9:56 AM
To: Geoffrey Zhu; r-help at stat.math.ethz.ch
Subject: Re: [R] vectorizing an iterative process.
> x[i]=3D3D3D3Dx[i-1]+y[i-1] for all i, how can I do this without a loop?
It looks like
x <- cumsum(y)
What does 3D mean?
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Em=3D3D ail transmission cannot be guaranteed to be secure or error-free.
______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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The information in this email or in any file attached hereto is=3D0A=3D
intended only for the personal and confidential use of the
individual=3D0A=3D or entity to which it is addressed and may contain
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intended recipient of=3D0A=3D this message you are hereby notified that any
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strictly prohibited. This communi=3D cation is for information purposes
only and should not be regarded as an off=3D er to sell or as a
solicitation of an offer to buy any financial product. Em=3D ail
transmission cannot be guaranteed to be secure or error-free.
______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
_______________________________________________________=0A=0A=0AThe information
in this email or in any file attached hereto is=0Aintended only for the personal
and confidential use of the individual=0Aor entity to which it is addressed and
may contain information that is=0Aproprietary and confidential. If you are not
the intended recipient of=0Athis message you are hereby notified that any
review, dissemination,=0Adistribution or copying of this message is strictly
prohibited. This communication is for information purposes only and should not
be regarded as an offer to sell or as a solicitation of an offer to buy any
financial product. Email transmission cannot be guaranteed to be secure or
error-free.