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mkoetse
Netherlands
Posts |
 Posted - 01/03/2004 : 06:22:11 AM
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Hai,
I tried to write a little code to find a certain value in a dataset:
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void TestforTurnon()
{
Worksheet wks = Project.ActiveLayer();
Dataset ds1(wks,0);
Dataset ds2(wks,4);
int rown = 1;
double value = 0.1;
double turnon;
int datsize = ds1.GetSize();
printf("datsize = %i\n", datsize);
do
{
printf("ds2[rown] = %3.2d\n", ds2[2]);
if (ds2[rown]>=value);
{
break;
}
rown+=1
} while (rown <= datsize);
turnon = ds1[rown];
printf("turn on = %1.1d\n", turnon);
}
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Here is what the function returned:
datsize = 242
ds2[rown] = -1205768431 (with rown = 1, the value in worksheet column is 0.06785, actually!)
turn on = -1.9
And here what it should be:
datsize = 242
ds2[rown] = 0.14414 (with rown = 51)
turn on = 3.0
I have no clue why I get this wierd number for the ds2[rown] and since it is negative the loop should al least start shouldn't it?
Any clues here?
Marc
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cpyang
USA
1406 Posts |
Posted - 01/03/2004 : 10:50:38 AM
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For one thing, Origin C is C/C++ so all indexing must be 0 offset. So you need to begin with rown = 0 and to test with
while(rown < datsize);
This might be confusing, as the visual display is 1 offset.
CP
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mkoetse
Netherlands
Posts |
Posted - 01/03/2004 : 1:25:46 PM
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I know the offset of the rownumbers is 0. But this is not a problem, since the data is > 0.1 at row 51. Actually I get the feeling that the number that is returned is actually a NANUM, and that is something I do not understand at all. I checked the datasets format, both nummeric and text or nummeric give the same results. To make it even more bizar: ds1 is the Xvalue column. It starts at -2 and increases with delta = 0.1. ds1[rown] returns 1717986918 (with rown = 1) were it should be -1.9!
Marc
Edited by - mkoetse on 01/03/2004 1:26:55 PM |
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Mike Buess
USA
3037 Posts |
Posted - 01/03/2004 : 2:07:06 PM
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I think the problem lies in the way you've formatted your output. %d expects an integer value. Try %f instead...
printf("ds2[rown] = %3.2f\n", ds2[2]);
-and-
printf("turn on = %1.1f\n", turnon);
Hope that helps.
Mike Buess
Origin WebRing Member |
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mkoetse
Netherlands
Posts |
Posted - 01/03/2004 : 2:13:05 PM
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At least the output is okay now, Thanks!
One prob resolved, but the loop still does not work, it only goes through once, although the condition is not met. Any idea what the problem might be?
Marc
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cpyang
USA
1406 Posts |
Posted - 01/03/2004 : 2:51:13 PM
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Your loop looks like it will only go through all the values once. Maybe post the whole code again?
Also, it seems that you will be much better off in using built-in functions like Data_List and Data_Table to do what you are trying to do. It is also correct that if there are missing values in your data, you will need to test for them and skip them, like
if(!is_missing_value(ds2[rown]))
{
}
CP
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mkoetse
Netherlands
Posts |
Posted - 01/04/2004 : 05:09:50 AM
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I tried the build in functions but non of them did show the expected behavior neither. The loop goes directly in the IF statement and thatshould not happen since the data is amaller than the test value. As far as know 0.069 < 0.1. The datasets are called corectly by the way.
MMK
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Mike Buess
USA
3037 Posts |
Posted - 01/04/2004 : 09:44:26 AM
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Hi Marc,
I don't know what your code looks like with Data_Table, but there is a semicolon placement error in your original code that will cause a premature break from the loop...
if (ds2[rown]>=value);
{
break;
}
rown+=1
-should be-
if (ds2[rown]>=value)
{
break;
}
rown+=1;
That should fix your loop but Data_Table and Data_List are surely more efficient.
...This is an example using Data_table.void TestforTurnon2()
{
Worksheet wks = Project.ActiveLayer();
Dataset ds1(wks,0);
Dataset ds2(wks,4);
int datsize = ds1.GetSize();
printf("datsize = %i\n", datsize);
double value = 0.1;
double turnon1 = Data_table(value, &ds1, &ds2);
printf("turn on = %1.1f\n", turnon1); // interpolated value
Dataset ds;
ds.Data(0,datsize-1); // create dataset containing C/C++ row numbers
int rown = (int) Data_table(value, &ds, &ds2);
//rown += 1; // this might be needed to agree with value obtained by your loop
double turnon2 = ds1[rown];
printf("turn on = %1.1f\n", turnon2); // nearest value
}
Mike Buess
Origin WebRing Member
Edited by - Mike Buess on 01/04/2004 10:55:59 AM
Edited by - Mike Buess on 01/04/2004 11:19:42 AM |
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mkoetse
Netherlands
Posts |
Posted - 01/04/2004 : 12:31:18 PM
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Woauw,
Indeed removing the semicolon did do the trick. Miljon thanks for that!
Your 2nd solution as such is not working, but I'll give it a thought over (and try to understant it) first before commenting in more detail.
Thanks a lot again,
MMK
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More unexpected behavior