[R] rounding off problem.....

[akshay kulkarni]

dear EB,
                 I checked the Rmpfr package. Thats exactly what I needed....! Thanks a lot.

very many thanks for your time and effort,
yours sincerely,

AKSHAY M KULKARNI


________________________________
From: Eric Berger <ericjberger using gmail.com>
Sent: Friday, March 8, 2019 6:31 PM
To: akshay kulkarni
Cc: R help Mailing list
Subject: Re: [R] rounding off problem.....

"Is there any way ..."
Two quick answers:
1. using base R functions and data types the answer is 'no' - a double (i.e. numeric) contains about 15 significant digits.
    So 5.678e-100 is fine but   0.01 + 5.678e-100 will keep the .0100000000000000  as the significant digits and "drop" the digits 80 or so places further to the right.
2. there are packages that provide for arbitrary precision calculations
    see R CRAN package Rmpfr
     https://cran.r-project.org/web/packages/Rmpfr/vignettes/Rmpfr-pkg.pdf

HTH,
Eric

On Fri, Mar 8, 2019 at 2:39 PM akshay kulkarni <akshay_e4 using hotmail.com<mailto:akshay_e4 using hotmail.com>> wrote:
dear members....
                                 here is a piece of my code:

> tail(YLf14,15)
 [1] 5.706871e-217 2.563877e-218 2.823295e-218 2.694622e-222 1.777409e-226
 [6] 1.134403e-201 5.269464e-215 2.272121e-219 2.794970e-223 1.630978e-187
[11] 1.721529e-213 5.859815e-178 4.842612e-222 1.333685e-193 1.256051e-174
> YLf16 <- YLf14 + 0.001
> tail(YLf16,15)
 [1] 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001
[13] 0.001 0.001 0.001

Is there any way to avoid the rounding off of YLf16 to 0.001, and take exact values?

very many thanks for your time and effort......
yours sincerely,
AKSHAY M KULKARNI


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