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Please find attached my proposal for a bugfix. The experts might to
better, though.
Uwe Ligges
[EMAIL PROTECTED] wrote:
> Yes, this one is a bug in CreateAtVector, plot.c.
> It already has the lines:
>
>
> /* Debugging: When does the following happen... ? */
> if (umin > umax)
> warning("CreateAtVector \"log\"(from axis()): "
> "usr[0] = %g > %g = usr[1] !", umin, umax);
>
>
> And now we know that it happens if (and only if?????) the logarithmic
> scale is not very small (i.e. axp[2] > 0, this is equal to R's
> par("yaxp")[3] in your example) and the axis are reversed (umin > umax).
>
> I'll try to provide a fix which should be possible by reversing
> arguments axp and usr in this case and returning a reversed at ...
>
> Uwe Ligges
>
>
>
>
> [EMAIL PROTECTED] wrote:
>
>
>>Full_Name: Christian Marquardt
>>Version: 2.1.0
>>OS: Linux (Redhat 9)
>>Submission from: (NULL) (151.170.240.10)
>>
>>Following the advice of a reader of R-help, I would now like to submit this
>>as a
>>bug report:
>>
>>Say we have
>>
>> x = seq(1,3, by = 0.01)
>> y = exp(x)
>>
>>Plotting and reversing linear axis is fine
>>
>> plot(x,y)
>> plot(x,y, ylim = c(30,1))
>>
>>as is a usual log-plot:
>>
>> plot(x,y, log = "y", ylim = c(1,30))
>>
>>However,
>>
>> plot(x,y, log = "y", ylim = c(30,1))
>>
>>fails with
>>
>> Error in axis(2, ...) : log - axis(), 'at' creation, _SMALL_ range:
>>invalid {xy}axp or par;
>> axp[0]= 10, usr[0:1]=(34.3721,0.872801)
>> In addition: Warning message:
>> CreateAtVector "log"(from axis()): usr[0] = 34.3721 > 0.872801 = usr[1] !
>>
>>
>>According to Petr Pikal <petr.pikal -at- precheza.cz>, replacing the ylim
>>argument by ylim = c(30,1.2) helps in the above example; but in my real world
>>applications, it's actually difficult to find a working value for ylim.
>>
>>I hope this is useful,
>>
>> Christian.
>>
>>______________________________________________
>>R-devel@stat.math.ethz.ch mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
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--- plot.c-orig 2005-05-27 10:38:39.851718400 +0200
+++ plot.c 2005-05-27 11:40:10.118060800 +0200
@@ -778,8 +778,10 @@
* The resulting REAL vector must have length >= 1, ideally >= 2
*/
SEXP at = R_NilValue;/* -Wall*/
- double umin, umax, dn, rng, small;
+ SEXP atr = R_NilValue;/* for reversed log axis with axp[2]>0 */
+ double umin, umax, dn, rng, small, reversed;
int i, n, ne;
+ reversed = 0.; /* for reversed log axis with axp[2]>0 */
if (!logflag || axp[2] < 0) { /* --- linear axis --- Only use axp[] arg. */
n = fabs(axp[2]) + 0.25;/* >= 0 */
dn = imax2(1, n);
@@ -799,6 +801,19 @@
n = 1,2,3. see switch() below */
umin = usr[0];
umax = usr[1];
+
+ if (umin > umax && axp[0] > axp[1]){
+ /* if we have log axis, axp[2]>0 and reversed axis, many following
calculations will fail
+ (assuming umin < umax etc.), hence simply reverse usr and axp at
first.
+ At the end reverse output of atr(eversed) back again. */
+ umin = usr[1];
+ umax = usr[0];
+ reversed = axp[0];
+ axp[0] = axp[1];
+ axp[1] = reversed;
+ reversed = 1.;
+ }
+
/* Debugging: When does the following happen... ? */
if (umin > umax)
warning("CreateAtVector \"log\"(from axis()): "
@@ -899,7 +914,15 @@
axp[2]);
}
}
- return at;
+ if(reversed == 1.){
+ /* we have to reverse the output back again (reversed log axis with
axp[2]>0) */
+ atr = allocVector(REALSXP, n);
+ for (i = 0; i < n; i++)
+ REAL(atr)[i] = REAL(at)[n-i-1];
+ return atr;
+ }
+ else
+ return at;
}
static double ComputePAdjValue(double padj, int side, int las)
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