You avoid the call to cmdscale() by supplying your own starting configuration
(see the manual page for the y= argument). You could still hit other barriers
within isoMDS() or insufficient memory on your computer.
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Kawashima, Masayuki
Sent: Wednesday, November 5, 2014 10:51 PM
To: r-help at r-project.org
Subject: [R] limit of cmdscale function
Hi
We have a few questions regarding the use of the "isoMDS" function.
When we run "isoMDS" function using 60,000 x 60,000 data matrix,
we get the following error message:
------------------------------------
cmdscale(d, k) : invalid value of 'n'
Calls: isoMDS -> cmdscale
------------------------------------
We checked the source code of "cmdscale" and found the following
limitation:
------------------------------------
## we need to handle nxn internally in dblcen
if(is.na(n) || n > 46340) stop("invalid value of 'n'")
------------------------------------
1. This cmdscale limitation ('n > 46340') is due to the limitation of
BLAS and LAPACK variables(int4) which can only handle '2^31-1' amount of
data?
2. Is there any workaround to run isoMDS using large data (i.e. greater than
46340)?
We would like to run isoMDS using a maximum of 150,000x150,000 data matrix.
Best regards
Masayuki Kawashima
Email: kawasima.m at jp.fujitsu.com
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