R help - May 2008 - Is there in R a function equivalent to the mround, as found in most spreadsheets?

Dear R-users,
I have the following problem

In a lab experiment I have to mix three solutions to get different 
concentrations of various molecules in a cuvette

I've used R to calculate the necessary ?liters for each of the level of 
the experiment and I must confess that it is more useful and easier to 
achieve the results than using spreadsheets.

But there's a problem.

Imagine that for a particular cuvette (I have 112 different cuvettes !!) 
you have to mix the following volumes of solution A, B, and C respectively.

c(1803.02, 193.51, 3.47)

Each solution is to be taken with 3 different pipettes (5000, 250 and 10 
?L Volume max) and each of those delivers volumes in steps of 50 ?L,  5 
?L  or 1?L, respectively
Since the above values  would eventually become

c(1800, 195, 3)

it is then necessary to recalculate all the final concentrations
of A, B and C, because the volumes are changed.


I know that in most spreadsheets (Calc in Open Office, Gnumeric, Excel 
and so on)
there's a function such as

mround(num; num)

that give the results I need, but I want to learn more on R functions.


I played a little with R functions such as

round, signif, ceiling, trunc, and floor

but without success.
Any hint to solve this problem ?

Thanks a lot

http://www.openofficetips.com/blog/archives/2005/04/rounding_to_the.html
http://www.gnome.org/projects/gnumeric/doc/gnumeric-MROUND.shtml

-- 
Ottorino-Luca Pantani, Universit? di Firenze
Dip. Scienza del Suolo e Nutrizione della Pianta
P.zle Cascine 28 50144 Firenze Italia
Tel 39 055 3288 202 (348 lab) Fax 39 055 333 273 
OLPantani at unifi.it  http://www4.unifi.it/dssnp/

On 5/6/2008 12:07 PM, Dr. Ottorino-Luca Pantani wrote:
> Dear R-users,
> I have the following problem
> 
> In a lab experiment I have to mix three solutions to get different 
> concentrations of various molecules in a cuvette
> 
> I've used R to calculate the necessary ?liters for each of the level of
> the experiment and I must confess that it is more useful and easier to 
> achieve the results than using spreadsheets.
> 
> But there's a problem.
> 
> Imagine that for a particular cuvette (I have 112 different cuvettes !!) 
> you have to mix the following volumes of solution A, B, and C respectively.
> 
> c(1803.02, 193.51, 3.47)
> 
> Each solution is to be taken with 3 different pipettes (5000, 250 and 10 
> ?L Volume max) and each of those delivers volumes in steps of 50 ?L,  5 
> ?L  or 1?L, respectively
> Since the above values  would eventually become
> 
> c(1800, 195, 3)
> 
> it is then necessary to recalculate all the final concentrations
> of A, B and C, because the volumes are changed.
> 
> 
> I know that in most spreadsheets (Calc in Open Office, Gnumeric, Excel 
> and so on)
> there's a function such as
> 
> mround(num; num)
> 
> that give the results I need, but I want to learn more on R functions.
> 
> 
> I played a little with R functions such as
> 
> round, signif, ceiling, trunc, and floor
> 
> but without success.
> Any hint to solve this problem ?

I believe this function matches the description in OOO:

mround <- function(number, multiple) multiple * round(number/multiple)

Duncan Murdoch

Hi Ottorino,
You could just use the modulus operator "%%" as
follows:
> x<-c(1803.02, 193.51, 3.47);
> x-x%%c(50,5,1) #just using the modulus operator
[1] 1800  190    3

thanks


Dr. Ottorino-Luca Pantani wrote:
> 
> Dear R-users,
> I have the following problem
> 
> In a lab experiment I have to mix three solutions to get different 
> concentrations of various molecules in a cuvette
> 
> I've used R to calculate the necessary ?liters for each of the level of
> the experiment and I must confess that it is more useful and easier to 
> achieve the results than using spreadsheets.
> 
> But there's a problem.
> 
> Imagine that for a particular cuvette (I have 112 different cuvettes !!) 
> you have to mix the following volumes of solution A, B, and C
> respectively.
> 
> c(1803.02, 193.51, 3.47)
> 
> Each solution is to be taken with 3 different pipettes (5000, 250 and 10 
> ?L Volume max) and each of those delivers volumes in steps of 50 ?L,  5 
> ?L  or 1?L, respectively
> Since the above values  would eventually become
> 
> c(1800, 195, 3)
> 
> it is then necessary to recalculate all the final concentrations
> of A, B and C, because the volumes are changed.
> 
> 
> I know that in most spreadsheets (Calc in Open Office, Gnumeric, Excel 
> and so on)
> there's a function such as
> 
> mround(num; num)
> 
> that give the results I need, but I want to learn more on R functions.
> 
> 
> I played a little with R functions such as
> 
> round, signif, ceiling, trunc, and floor
> 
> but without success.
> Any hint to solve this problem ?
> 
> Thanks a lot
> 
> http://www.openofficetips.com/blog/archives/2005/04/rounding_to_the.html
> http://www.gnome.org/projects/gnumeric/doc/gnumeric-MROUND.shtml
> 
> -- 
> Ottorino-Luca Pantani, Universit? di Firenze
> Dip. Scienza del Suolo e Nutrizione della Pianta
> P.zle Cascine 28 50144 Firenze Italia
> Tel 39 055 3288 202 (348 lab) Fax 39 055 333 273 
> OLPantani at unifi.it  http://www4.unifi.it/dssnp/
> 
> ______________________________________________
> R-help at r-project.org 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.
> 
> 

-----
Yasir H. Kaheil, Ph.D.
Catchment Research Facility
The University of Western Ontario 

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Dear R-users,

I have the following problem

In a lab experiment I have to mix three solutions to get different 
concentrations of various molecules in a cuvette

I've used R to calculate the necessary ?liters for each of the level of 
the experiment and I must confess that it is more useful and easier to 
achieve the results than using spreadsheets.

But there's a problem.

Imagine that for a particular cuvette (I have 112 different cuvettes !!) 
you have to mix the following volumes of solution A, B, and C respectively.

c(1803.02, 193.51, 3.47)

Each solution is to be taken with 3 different pipettes (5000, 250 and 10 
?L Volume max) and each of those delivers volumes in steps of 50 ?L,  5 
?L  or 1?L, respectively
Since the above values  would eventually become

c(1800, 195, 3)

it is then necessary to recalculate all the final concentrations
of A, B and C, because the volumes are changed.


I know that in most spreadsheets (Calc, Gnumeric, Excel 
and so on) there's a function such as

mround(num; num)

that give the results I need, but I want to learn more on R functions.


I played a little with R functions such as

round, signif, ceiling, trunc, and floor

but without success.
Any hint to solve this problem ?

Thanks a lot

http://www.openofficetips.com/blog/archives/2005/04/rounding_to_the.html
http://www.gnome.org/projects/gnumeric/doc/gnumeric-MROUND.shtml

-- 
Ottorino-Luca Pantani, Universit? di Firenze
Dip. Scienza del Suolo e Nutrizione della Pianta
P.zle Cascine 28 50144 Firenze Italia
Tel 39 055 3288 202 (348 lab) Fax 39 055 333 273 
OLPantani at unifi.it  http://www4.unifi.it/dssnp/

Hello Luca.


Dr. Ottorino-Luca Pantani wrote:
> 
> ...
> 
> c(1803.02, 193.51, 3.47)
> 
> Each solution is to be taken with 3 different pipettes (5000, 250 and 10 
> ?L Volume max) and each of those delivers volumes in steps of 50 ?L,  5 
> ?L  or 1?L, respectively
> Since the above values  would eventually become
> 
> c(1800, 195, 3)
> 
> ...
> 
You find a complete solution at 
  http://albertosantini.blogspot.com/2008/05/mround.html

It checks the sign of the number and the multiple and it hacks the issue of
rounding off a 5 respect IEC 60559 standard.

The test cases are:

mround(10, 3) # 9
mround(-10, -3) # -9
mround(1.3, 0.2) # 1.4
mround(5, -2) # error
mround(1.7, 0.2) # 1.8
mround(321.123, 0.12) # 321.12
mround(1803.02, 50) # 1800
mround(193.51, 5) # 195
mround(3.47, 1) # 3


Regards,
Alberto


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