I would think you could associate your dates to
BarIndex() and increment that by 100, something like...
BegISbar = Valuewhen( DateNum() == BegISdate,
BarIndex() );
EndISbar = Valuewhen( DateNum() == EndISdate,
BarIndex() );
...
for (FromISbarNum = BegISbar; FromISbarNum <= EndISbar;
FromISbarNum = FromISbarNum + StepIS)
----- Original Message -----
Sent: Tuesday, May 12, 2009 8:18 PM
Subject: [amibroker] How to increment
dates in a for loop?
Hello,
hoping someone can point out a good method for incrementing dates. I am
currently trying to build a basic Walk-Forward engine that does an
Optimization on In-Sample (IS) data using one formula, followed
by an Optimization on Out-Of-Sample (OOS) data using a second
formula.
This is different than AB's built-in WF engine, which
performs an Optimization, followed by a Backtest using only one formula.
Anyway, I
am currently stuck right at the beginning, trying to figure out a sensible way
to increment dates. This is what I have so far:
// datenum format: 10000 * (year - 1900) + 100 *
month + day,
// so 2001-12-31 becomes 1011231 and 1995-12-31 becomes
951231
BegISdate = 1031201;
EndISdate =
1090201;
StepIS =
100;
BegOOSdate =
1050101;
EndOOSdate =
1090301;
StepOOS =
100;
Formula1 = "F:\\formula1.afl";
Formula2 = "F:\\formula2.afl";
Database = "F:\\AB
Databases\\MyDB";
Settings =
"F:\\My Settings.ABS";
for (FromISdateNum = BegISDate; FromISdateNum <= EndISdate;
FromISdateNum = FromISdateNum +
StepIS)
{
AB = CreateObject("Broker.Application");
// Etc. .........
Now the above
won't exactly work because simply adding 100 to a datenum will not allow the
datenum to correctly roll over from December to January. For example,
incrementing 1031201 by 100 yields 1031301 instead of 1040101.
I know I
can first convert the datenum to a string, then build a parser that splits the
datenum apart and analyzes the last four digits, converting 1301 to 0101, then
reconstitute the string and reconvert to a datenum again. But that all feels
rather convoluted.
Is there an easier way to increment dates in AFL?
I've searched the help manual and can't seem to find anything. What if I first
converted to DateTime format? Is there an easy way to step through that format
month by month?
Any pointers much appreciated.
And when I
complete the WF Opt-Opt engine, I will be happy to post it here, in case
anyone else has a need for it.
Thanks!
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