precision problem
all.equal is helpful when I am comparing equality of two matrices. However, when I am comparing two individual number with > or < is my best bet doing if( abs(x - y) < tolerence) or is there a function like all.equal that has the same default tolerence?
On 5/25/05, Omar Lakkis <uofiowa at gmail.com> wrote:
Thank you all. all.equal is very helpful since I am also interested in finding the mismatched prices. On 5/25/05, John Fox <jfox at mcmaster.ca> wrote:
Dear Omar, Perhaps I'm missing something, but why not just subtract one matrix from the other and test the difference in relation to the precision that you require for the comparison? E.g., to test near equality, something like, abs(A - B) < 1e-13. I hope this helps, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox --------------------------------
-----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Omar Lakkis Sent: Wednesday, May 25, 2005 9:09 AM To: r-help at stat.math.ethz.ch Subject: [R] precision problem I have prices that I am finding difficult to compare with ==,
and >, due to precision. For example: the numbers should
match, with '==', but they differ in the magnitude of 1e-14 due to bunch of calculations that I run on them. Programming with java, I am used to implementing a function that compares the difference between the numbers to a pre determined precision factor. This could be very slow when I have two matrices of numbers that I could otherwise compare with a simple '==', '>' or '<' in R. What is teh best solution for this problem? Can I control the precision of ==, > and < without having to reimplement the operations in a slow way?
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