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Subject: [OASIS Issue Tracker] Issue Comment Edited: (OFFICE-916) PublicComment: ODFF: yet more suggestions
[ http://tools.oasis-open.org/issues/browse/OFFICE-916?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15110#action_15110 ]
Eike Rathke edited comment on OFFICE-916 at 10/30/09 4:46 PM:
--------------------------------------------------------------
Several topics in that comment, marking my comments on each with [ed:]
PMT
- Constraints should have Nper>0 and integer
- For clarity, should specify that with PayType=1 the first payment is made on
the same day the loan is taken out.
- The formula is unstable at very low rates. Better to use an approximation,
but Calc at least does not do so, and will produce #VALUE! errors. Excel 97
similarly gives #DIV/0!
[ed:] TODO: add constraints and PayType=1 definition, and a note that the
formula may be unstable at very low rates.
CORREL
- Currently as defined, also allows different dimensions for the two
parameters - if this is intended should be explicitly stated (NB Calc
expects the same dims).
[ed:] That's OFFICE-2175
- Also it's a redundant function - it's identical to Pearson.
[ed:] the current draft states that, no action needed.
PV
- Payment can be omitted if fv is given.
[ed:] TODO: check how that should work.
DISC
- should divide by YEARFRAC, not multiply I think.
[ed:] present in current draft, no action needed.
SYD
- "sum-of-years' digits method" This phrase appears to be copied from Excel.
- I'd suggest either "sum- of-years' digits method" or "sum of years'-digits
method".
[ed:] TODO: any native English speaker who can provide insight?
- Formula is at:
http://wiki.services.openoffice.org/w/index.php?title=Documentation/How_Tos/Calc:_SYD_function
[ed:] TODO: add formula.
DDB
- "I don't know how to put this into the equations."
- See:
http://wiki.services.openoffice.org/wiki/Documentation/How_Tos/Calc:_DDB_function
[ed:] TODO: add formula.
DOLLARDE
- Does not return currency; returns a number.
[ed:] TODO: change return to Number. Same for DOLLARFR function.
TBILLEQ
- Excel gives the formula:
"TBILLEQ is calculated as TBILLEQ = (365 x rate)/360-(rate x DSM), where DSM
is the number of days between settlement and maturity computed according to
the 360 days per year basis."
That's wrong - should be (365 x rate)/[360-(rate x DSM)]. Also: using the
360 day year is vital information which needs to be included.
[ed:] TODO: add formula.
- "bond-equivalent yield for a treasury bill" is probably lifted from Excel's
Help, and comes across as jargon; needs more explanation, especially for
non-US people.
[ed:] TODO: any native English speaker knowledgeable in that domain?
ISPMT
- "amortized investment" is jargon, possibly not readily understood except in
the US. It gets no useful hits from Google.
[ed:] TODO: any native English speaker knowledgeable in that domain?
ODDFYIELD
- doesn't need to say "yield per 100 units" - yield is irrespective of this.
[ed:] TODO: is it? what about the Redemption parameter then, that says "the
redemption value per 100 currency units face value".
XNPV
- Excel documentation gives the formula. It's based on 365 days only. They've
missed out a minus sign. More detail is required to define this function.
[ed:] TODO: who can provide insight?
- Excel's help also seems to have an error - I don't think it is *necessary*
to have a negative entry - first entry could be a payment. The day count
appears to be the actual day count (366 in a leap year).
[ed:] TODO: who can provide insight?
FTEST
- "Summary: Returns the result of an F test (the probability that two datasets
have come from the same total population)"
Excel says it tests the probability that the *variances* are not
significantly different (which is not the same as coming from the same total
population).
[ed:] TODO: who can provide insight?
- "An F-test returns the one-tailed probability" Excel currently describes
this as the 2-tailed probability. I believe that is correct (see
http://www.coventry.ac.uk/ec/~nhunt/pottel.pdf). Old versions of Excel eg 97
describe it as one tailed. It would be worth someone with real knowledge
checking this out.
[ed:] TODO: who can provide insight?
VDB
- http://wiki.services.openoffice.org/wiki/Documentation/How_Tos/Calc:_VDB_function
has a rather more detailed explanation, and a link to (different) bugs in
Calc and Excel.
[ed:] TODO: check that.
was (Author: erack):
Several topics in that comment, marking my comments on each with [ed:]
PMT
- Constraints should have Nper>0 and integer
- For clarity, should specify that with PayType=1 the first payment is made on
the same day the loan is taken out.
- The formula is unstable at very low rates. Better to use an approximation,
but Calc at least does not do so, and will produce #VALUE! errors. Excel 97
similarly gives #DIV/0!
[ed:] TODO: add constraints and PayType=1 definition, and a note that the
formula may be unstable at very low rates.
CORREL
- Currently as defined, also allows different dimensions for the two
parameters - if this is intended should be explicitly stated (NB Calc
expects the same dims).
[ed:] TODO: clarify on that, see also OFFICE-790 comment on CORREL.
- Also it's a redundant function - it's identical to Pearson.
[ed:] the current draft states that, no action needed.
PV
- Payment can be omitted if fv is given.
[ed:] TODO: check how that should work.
DISC
- should divide by YEARFRAC, not multiply I think.
[ed:] present in current draft, no action needed.
SYD
- "sum-of-years' digits method" This phrase appears to be copied from Excel.
- I'd suggest either "sum- of-years' digits method" or "sum of years'-digits
method".
[ed:] TODO: any native English speaker who can provide insight?
- Formula is at:
http://wiki.services.openoffice.org/w/index.php?title=Documentation/How_Tos/Calc:_SYD_function
[ed:] TODO: add formula.
DDB
- "I don't know how to put this into the equations."
- See:
http://wiki.services.openoffice.org/wiki/Documentation/How_Tos/Calc:_DDB_function
[ed:] TODO: add formula.
DOLLARDE
- Does not return currency; returns a number.
[ed:] TODO: change return to Number. Same for DOLLARFR function.
TBILLEQ
- Excel gives the formula:
"TBILLEQ is calculated as TBILLEQ = (365 x rate)/360-(rate x DSM), where DSM
is the number of days between settlement and maturity computed according to
the 360 days per year basis."
That's wrong - should be (365 x rate)/[360-(rate x DSM)]. Also: using the
360 day year is vital information which needs to be included.
[ed:] TODO: add formula.
- "bond-equivalent yield for a treasury bill" is probably lifted from Excel's
Help, and comes across as jargon; needs more explanation, especially for
non-US people.
[ed:] TODO: any native English speaker knowledgeable in that domain?
ISPMT
- "amortized investment" is jargon, possibly not readily understood except in
the US. It gets no useful hits from Google.
[ed:] TODO: any native English speaker knowledgeable in that domain?
ODDFYIELD
- doesn't need to say "yield per 100 units" - yield is irrespective of this.
[ed:] TODO: is it? what about the Redemption parameter then, that says "the
redemption value per 100 currency units face value".
XNPV
- Excel documentation gives the formula. It's based on 365 days only. They've
missed out a minus sign. More detail is required to define this function.
[ed:] TODO: who can provide insight?
- Excel's help also seems to have an error - I don't think it is *necessary*
to have a negative entry - first entry could be a payment. The day count
appears to be the actual day count (366 in a leap year).
[ed:] TODO: who can provide insight?
FTEST
- "Summary: Returns the result of an F test (the probability that two datasets
have come from the same total population)"
Excel says it tests the probability that the *variances* are not
significantly different (which is not the same as coming from the same total
population).
[ed:] TODO: who can provide insight?
- "An F-test returns the one-tailed probability" Excel currently describes
this as the 2-tailed probability. I believe that is correct (see
http://www.coventry.ac.uk/ec/~nhunt/pottel.pdf). Old versions of Excel eg 97
describe it as one tailed. It would be worth someone with real knowledge
checking this out.
[ed:] TODO: who can provide insight?
VDB
- http://wiki.services.openoffice.org/wiki/Documentation/How_Tos/Calc:_VDB_function
has a rather more detailed explanation, and a link to (different) bugs in
Calc and Excel.
[ed:] TODO: check that.
> Public Comment: ODFF: yet more suggestions
> ------------------------------------------
>
> Key: OFFICE-916
> URL: http://tools.oasis-open.org/issues/browse/OFFICE-916
> Project: OASIS Open Document Format for Office Applications (OpenDocument) TC
> Issue Type: Bug
> Components: OpenFormula
> Affects Versions: ODF 1.2
> Reporter: Robert Weir
> Assignee: Eike Rathke
> Priority: Blocker
> Fix For: ODF 1.2
>
>
> Copied from office-comment list
> Original author: "David King" <openoffice@drking.plus.com>
> Original date: 31 Jul 2008 20:30:12 -0000
> Original URL: http://lists.oasis-open.org/archives/office-comment/200807/msg00112.html
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