Dear all,
sorry about the noise. I have to stop now, here is what I got so far. The
patch below shows how that we need to explicitely trap errors outside the
calculation of the function, these are mostly calculations of length.
However, sin(1/x)*exp(-1/x) will not be drawn nicely with this patch, even with
clipping on. If we pass adaptive==false, then we get a plot, though.
I think that it should be possible to get an image even with adaptive==true,
but I have no time to analyse the adaptivePlot algorithm. Probably one also
needs to analyse the clipping algorithm.
This patch does not fix the issue with
g:DFLOAT->DFLOAT := x +-> 10^300
draw(g, -1..1)
taking forever. Possibly this is an issue of the plotting routines (written in
C) themselves.
Martin
Index: plot.spad.pamphlet
===================================================================
--- plot.spad.pamphlet (revision 419)
+++ plot.spad.pamphlet (working copy)
@@ -279,8 +279,11 @@
[ f, [nRange,xRange,yRange], c, q]
adaptivePlot(curve,tRange,xRange,yRange,pixelfraction) ==
+ output("adaptivePlot")$OutputPackage
xDiff := hi xRange - lo xRange
+ output(xDiff::OutputForm)$OutputPackage
yDiff := hi yRange - lo yRange
+ output(yDiff::OutputForm)$OutputPackage
xDiff = 0 or yDiff = 0 => curve
l := lo tRange; h := hi tRange
(tDiff := h-l) = 0 => curve
@@ -316,6 +319,7 @@
todo1 := todot; todo2 := todop
n : I := 0
while not null todo1 repeat
+ output("adaptivePlot: while")$OutputPackage
st := first(todo1)
t0 := first(st); t1 := second(st); t2 := third(st)
if t2 > h then leave
@@ -329,8 +333,18 @@
x2 := xCoord third(sp); y2 := yCoord third(sp)
a1 := (x1-x0)/xDiff; b1 := (y1-y0)/yDiff
a2 := (x2-x1)/xDiff; b2 := (y2-y1)/yDiff
- s1 := sqrt(a1**2+b1**2); s2 := sqrt(a2**2+b2**2)
- dp := a1*a2+b1*b2
+ output("adaptivePlot: norms")$OutputPackage
+ output(a1::OutputForm)$OutputPackage
+ output(a2::OutputForm)$OutputPackage
+ output(b1::OutputForm)$OutputPackage
+ output(b2::OutputForm)$OutputPackage
+ s1Safe := trapNumericErrors(sqrt(a1**2+b1**2))$Lisp::Union(F,
"failed")
+ if s1Safe case "failed" then s1 := max()$F else s1 := s1Safe::F
+ s2Safe := trapNumericErrors(sqrt(a2**2+b2**2))$Lisp::Union(F,
"failed")
+ if s2Safe case "failed" then s2 := max()$F else s2 := s2Safe::F
+ dpSafe := trapNumericErrors(a1*a2+b1*b2)$Lisp::Union(F, "failed")
+ if dpSafe case "failed" then dp := max()$F else dp := dpSafe::F
+ output("adaptivePlot: norms done")$OutputPackage
s1 < maxLength and s2 < maxLength and _
(s1 = 0::F or s2 = 0::F or
@@ -387,6 +401,7 @@
todo1 := rest todo1
todo2 := rest todo2
if not null todo1 then (t := first(todo1); p := first(todo2))
+ output("adaptivePlot: while finished")$OutputPackage
n > 0 =>
NUMFUNEVALS := NUMFUNEVALS + n
t := curve.knots; p := curve.points
@@ -512,6 +527,7 @@
p
pointPlot(f:F -> P,tRange:R) ==
+ output("pointPlot1")$OutputPackage
p := basicPlot(f,tRange)
r := p.ranges
NUMFUNEVALS := minPoints()
@@ -521,6 +537,7 @@
[ true, rest r, r, nil(), [ p ] ]
pointPlot(f:F -> P,tRange:R,xRange:R,yRange:R) ==
+ output("pointPlot2")$OutputPackage
p := pointPlot(f,tRange)
p.display := [checkRange xRange,checkRange yRange]
p
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