integrate() (PR#1755)

[Bill.Venables@cmis.csiro.au]

There is no bug.  The error message tells you that your function gives a
result of the wrong length - that means your function should give a result
with length the same as that of the input argument, x.

Try either of the following

> integrate(function(x) 1 + 0*x, 0, 1)
> integrate(function(x) rep(1, length(x)), 0, 1)

If you spot the message in these it could be the start of a seminal lesson
on vectorization.

Bill Venables

-----Original Message-----
From: tcporco@mathepi.com [mailto:tcporco@mathepi.com]
Sent: Monday, July 08, 2002 10:33 AM
To: r-devel@stat.math.ethz.ch
Cc: R-bugs@biostat.ku.dk
Subject: integrate() (PR#1755)


Full_Name: Travis Porco
Version: 1.5.1 (6/17/2002)
OS: Suse Linux 7.1
Submission from: (NULL) (66.81.124.235)


This happens:
> integrate(function(x)1,0,1)
Error in integrate(function(x) 1, 0, 1) : evaluation of function gave a
result
of wrong length
> integrate(function(x)x^2,0,1)
0.3333333 with absolute error < 3.7e-15
> integrate(function(x){cat(x);1},0,1)
0.5 0.01304674 0.9869533 0.06746832 0.9325317 0.1602952 0.8397048 0.2833023
0.7166977
 0.4255628 0.5744372 0.002171418 0.9978286 0.03492125 0.9650787 0.1095911
0.8904089 
0.2186214 0.7813786 0.3528036 0.6471964Error in integrate(function(x){ :
evaluation of function gave a result of wrong length

This is clearly incorrect behavior.  I included case 2 to show that some
cases
are
working correctly.

Various other conditions produce the error message indicated.  Of course,
not
being able to 
integrate a constant is not in itself the problem; rather, function(x)1
generates the
same error that occurs in the real problem I'm working on.

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